DC-DC charger- which one?

[mijango]

Hi, I have decided to bite the bullet and move to a DC-DC charger for my 2010 D4 TDV6. I currently am running a Traxide dual battery system, though with regular charging trhough my ctek mx5.0 I'm still suffering problems with keeping the voltage up (some of you may remember my earlier posts) :o

I know there is some great feedback on the Traxide system, though I've heard several views that the Battery Mgt System in the D4's responds far better to the draw of current from a DC-DC setup as opposed to an isolator. Just one school of thought I know, but at least the DC-DC charger can still use the existing wiring.

So, my question is which DBS to go with? I am really tossing up between the Redarc BCDC1225
25A In-Vehicle Battery Charger/MPPT Regulator (BCDC1225) - REDARC (http://www.redarc.com.au/products/product/in-vehicle-battery-chargermppt-regulator-25a/)
and the Low Voltage version of the same model (BCDC1225-LV). Is the lower voltage (which I think is more a variable voltage) more suitable to the Battery Mgt system in the earlier D4's?

In terms of use, I will be using it to run a fridge while camping, plus an inverter for charging low power items such as phone chargers. I also tow a camper trailer with an in-house battery and occassionally charge it through the anderson at the back of the Disco (although do have solar panels which I usually use). I'd also like to have the option to charge the car dual batteries via solar by plugging into the anderson plug at the back of the car.

Any thoughts or advice much appreciated.. :)

[Mick_Marsh]

Oooohhhh!.
I suspect this may be an active, heated thread.

There has been lots of people posting on DC/DC chargers. Do a search.

My advice would be to get the most expensive one. The reason being, indications are they are bought by people who want to waste their money.

[Homestar]

Hang on, let me get comfortable....

https://www.aulro.com/afvb/images/imported/2015/04/153.jpg (http://www.sherv.net/)

Ok, I'm ready.

[RobA]

OK I'' have a crack at this

In the first instance you have raised several questions and issues which need additional information before anyone can actually reply in detail.

I have no idea of the duty cycle of the car so it would be useful to know if you run a deficit cycle. Which is lots of short trips that do not allow the system to fully top-up the starting battery. if that is the case then with your Traxide system all you really need is a decent battery charger and whilst there are plenty around we use the RedArc Smart Charger and have for the last 12 years or so given we helped design the thing.

I need an idea of the second/third battery you are using to understand if they are properly scaled for the work and demand you have as another piece of start point information. We are using the standard Traxide with a yellow top and our car sits in the garage a lot until taken out to play so I simply put the smart charger on the yellow top which also charges the starting battery concurrently. So far no issues at all.

You mention an inverter but no comment on output and duration of use so also very difficult to provide a professional view on that one I am afraid. We have a 400w one in the camper trailer and that with two AGM 150AH batteries keeps all things going overnight and the solar panels top the batteries up during most days.

We tow an Ultimate and given all modern vehicles have a lazy alternator, hence the invention of DC chargers to compensate for that little design fault, and to overcome that we simply but a RedArc BMS in the Ulti and that resolves the lack of volts coming back from the car via the Anderson plug. If you rely just on volts via Anderson plug camper batteries will not be charged

Our Traxide and RedArc setups both allow us to charge car and camper using our solar panels. Any decent auto electrician can do that as part of a fitout.

Overall 12 volt systems are one of the most talked about and vexed discussion items anywhere in my experience. The complexity of modern vehicle electronics is a very long way from vehicles made a decade ago but sadly many opinions have not kept pace with the issues so the risk of leading someone astray is relatively simple

So an interesting question which I hope will result in lots of constructive feedback for which this site is renown. As I am one of the beneficiaries of that advice and have put it to great use so far I am always happy to offer at least our experiences as a contribution to the informed debate

Regards

Rob

[clubagreenie]

Speak to Tim at traxide first, get his advice on his product and what it may be doing wrong. Then take his recommendation. If it's necessary he'll recommend a DC/DC, but I'll put my house and yacht on him not.

[Wheelan]

Ill chime in, Ctek 250s. Had them in 2 cars, no brainer, my batts have never been better. Just dont over tighten the screws, you have been warned. oh yeah, cheap too on ebay.

[Vern]

I have a friend who has the problem with his gu patrol, it runs a redarc duel battery system and charges a second battery, it also charges two batteries in the camper. It doesn't work very well.
His brother has the identical set up, but in a 100 series, his works perfectly.
From what I read, and don't really understand that well, the patrol alt works via the ecu?
Has been told to install a BC DC charger.

[drivesafe]

Hi mijango, before you go wasting money on a DC/DC device, get your D4 software updated.

There has been a lot of problems with D4s not charging their own cranking battery, let alone not being able to charge auxiliary/house batteries.

I have had a number of customers, who, after being told by the dealer's service staff, my system was causing the low charging voltage in their D4, they disconnect my system for a month or so only to still have the same problems.

In one case the customer had the hidden screen up when ever he was driving and he told me that not once in the month after disconnecting my system when the dealer accused my system as being the cause of his low voltage, did his operating voltage ( with the motor running ) ever get above 12.2v.

After a month of continual flat cranking batteries, he went back to the dealer, and told them his DBS had been disconnected for a month but he still had the same problem.

They check and found there was a software update.

It is for something called the GATEWAY MODULE in newer D4s and there will be other updates as well for earlier D4s.

The dealership carried out the update and the customer rang me as he was travelling back home from the dealers to tell me his alternator voltage was now 14.7v.

This problem started in the UK early last year and is happening here now.

So again, before you waste a bucket load of money on something you should not need, get the update done.

Here is the specific Land Rover info for the GATEWAY update. This will fix any "LOW BATTERY START MOTOR" messages and should fix any low voltage problems, but double check with your dealer to see if there an other updates.

TSB Number: LTB-00667-NAS-1
NHTSA Number: 10056435
TSB Date: August 1, 2014
Date Added to File: December 2, 2014
Failing Component: Electrical System: Software
Summary:
Land rover: due to gateway module (gwm) software issue, the instrument cluster and/or eco stop/start, fails to function and displays, intermittently, Battery warning message and warning lamp. Model 2014 lr4 (la).


With more than 4,000 D3s and D4s with my kits fitted, and other than the software update being needed, no one has ever needed a DC/DC device.

Furthermore, with out the update, if you fit a DC/DC device, you are more than likely to have a lot of flat cranking battery situations, if the up date is needed.

[Vern]

Tim, not to take over the original poster thread, but what do you think would be the cause of my mates gu patrol?

[Tombie]

RobA has asked the best compilation of questions pertinent to your use/needs..

Once you provide some feedback more assistance should easily flow your way.

Keep in mind DC-DC chargers are current limiting - in this case 25amp... And will actually increase charge time...

But enough of that; provide as much feedback as you can and we can move forward from there..

[Wheelan]

Furthermore, with out the update, if you fit a DC/DC device, you are more than likely to have a lot of flat cranking battery situations, if the up date is needed.

There is alot of great info here, and I am not knocking anyones system by any means, I think Traxide have a great product that has worked for many people (from what I read). My 2 cents forward is I have a similar setup now in the D4 2010 as I did in my Amarok. 100 ah in the back with just about everything aux running of it and a Ctek 250s charging it. I had concerns originally about running this system due to the charging characteristics of the Disco. Anyway I monitor the second battery voltage through a voltmeter mounted next to my inverter as I use my car electrics alot for work and for camping. My second battery charges very quickly and has the same sort or reserve as the same system in my other car. I have not had any flat starting batteries and if I want I can stick a huge solar panel into this system without a regulator. It is just working very well for me, again, just sayin'

[pwillo]

It is for something called the GATEWAY MODULE in newer D4s and there will be other updates as well for earlier D4s.

The dealership carried out the update and the customer rang me as he was travelling back home from the dealers to tell me his alternator voltage was now 14.7v.

This problem started in the UK early last year and is happening here now

Here is the specific Land Rover info for the GATEWAY update. This will fix any "LOW BATTERY START MOTOR" messages and should fix any low voltage problems, but double check with your dealer to see if there an other updates.

TSB Number: LTB-00667-NAS-1
NHTSA Number: 10056435
TSB Date: August 1, 2014
Date Added to File: December 2, 2014
Failing Component: Electrical System: Software
Summary:
Land rover: due to gateway module (gwm) software issue, the instrument cluster and/or eco stop/start, fails to function and displays, intermittently, Battery warning message and warning lamp. Model 2014 lr4 (la).



Tim

Is this the TSB for my vehicle, a 2013 D4?

My battery never seems to get above 12.5V, I have your system fitted and a dealer who seems to think 74% charged is fine.

Regards

[drivesafe]

Hi Wheelan here is the thing, with your system and your 100Ah battery, you had 80Ah available if you discharged your 100Ah down to it's safe limit of 20% SoC.

If you had one of my isolators, you would have had 125Ah available.

But even if you still only used the same 80Ah, then the two batteries in my system, your auxiliary and your cranking battery, will only be discharged down to about 60% SoC and this means your batteries would be fully charged in a shorter drive time than your single 100Ah battery could be with or with out your DC/DC device.

The recharge time in a D4 is even quicker with one of my isolators fitted.

Then add the fact that with short driving trips around town and my system will actually keep your cranking battery in a higher state of charge, something no other system can do.

[Blknight.aus]

I have a friend who has the problem with his gu patrol, it runs a redarc duel battery system and charges a second battery, it also charges two batteries in the camper. It doesn't work very well.
His brother has the identical set up, but in a 100 series, his works perfectly.
From what I read, and don't really understand that well, the patrol alt works via the ecu?
Has been told to install a BC DC charger.

it not interfaced correctly int othe stystm and his chargin system is not detecting when its drawing load appropriately.

then hes got high resistance joints and incorrect wiring sizes that are causing drop from the out put of the system to the batteries

so because his systems not coming up to full voltage hes getting a lower current flow throuh his DBS to the output side of the DBS and then hes dumping a heap of that due to the resistence of his wiring.

due to the overall lowered current draw the main battery never gets drained down enough to ramp the charging system into its higher charging rate, it just sits there trying to trickle charge the battery. Of course its more insiduous than that.

the BECM knows whats turned on so it tells the engine ECU to ramp the alternator to X amps to offset the expected draw of the vehicle electrics. of course your now drawing more than that because of the unknown draw of the DBS slowly charging the batteries down the back. and since the alternators only putting out just enough to deal with the vehicle load guess where most of those amps are coming from. Yep, the main vehicle battery. so eventually the voltge drops down enough for the ECU to realise that its low so it bumps the alternator up for a couple of minutes, and the battery voltage comes back up for a little while. Eventually the batteries down the back will get fully charged, assuming of course you dont have a load on them thats drawing down the second battery.

[drivesafe]

Tim

Is this the TSB for my vehicle, a 2013 D4?
The GATEWAY Module is in 2014 and 15 D4s


My battery never seems to get above 12.5V, I have your system fitted and a dealer who seems to think 74% charged is fine.

Regards

Hi pwillo, if your battery is 12.5v in the morning, before starting, then it is at 90% SoC and that is actually above the normal voltage found on a D4 that is NOT fitted with one of my systems, so my system is working as it should be.

This chart will help with battery charge levels.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg

[Vern]

it not interfaced correctly int othe stystm and his chargin system is not detecting when its drawing load appropriately.

then hes got high resistance joints and incorrect wiring sizes that are causing drop from the out put of the system to the batteries

so because his systems not coming up to full voltage hes getting a lower current flow throuh his DBS to the output side of the DBS and then hes dumping a heap of that due to the resistence of his wiring.

due to the overall lowered current draw the main battery never gets drained down enough to ramp the charging system into its higher charging rate, it just sits there trying to trickle charge the battery. Of course its more insiduous than that.

the BECM knows whats turned on so it tells the engine ECU to ramp the alternator to X amps to offset the expected draw of the vehicle electrics. of course your now drawing more than that because of the unknown draw of the DBS slowly charging the batteries down the back. and since the alternators only putting out just enough to deal with the vehicle load guess where most of those amps are coming from. Yep, the main vehicle battery. so eventually the voltge drops down enough for the ECU to realise that its low so it bumps the alternator up for a couple of minutes, and the battery voltage comes back up for a little while. Eventually the batteries down the back will get fully charged, assuming of course you dont have a load on them thats drawing down the second battery.so dave how does one fix this? Camper batteries will have the fridge load on them when driving/charging.
Cable sizes are fine, same size cables as in his brothers 100 series, all joins are OK. When we were away last I stuck my clamp meter (never go camping without it) on the camper batteries, whilst charging and was getting 6a each into them and the batteries were low, they were charging a lot better with the solar panel.

[drivesafe]

Hi Vern, the GU and the 100 have exactly the same charging setup and voltages, so if one is working and the other is not, then as Dave has already posted, There is a problem with the wiring and/or connections somewhere in the GU.

With two batteries in a low state, you should be seeing at least 25 amps per battery, so again, there is something wrong with the setup. ( PS ) this is with the motor idled up!

How is the earth return done?

[mijango]

Thanks to everyone for their inputs.. that's why I love this forum ;)

Rob - as mentioned, I regularly (at least once a month) have been charging using the Ctek MX5.0 charger through the anderson rear plug. While most trips are short (local city driving ~30mins), it usually only gets used at weekends or on longer trips about once a month.

In terms of the 2nd battery (no 3rd) it is a yellow top similar to yours as recommended by Tim when I purchased the traxide kit.

My inverter is fairly tame in terms of voltage and current draw. It is a 300W or thereabouts and only used for charging phones etc.. I don't think this is a big part of the problem here.

Tim - thanks. I had my independent (Coopers in St Peters) update the engine and gearbox software patches about 6 months ago following a Engine Fault System where the turbos deactivated while towing.

I'll definitely speak to Coopers about the software update also. Though it sounds like the symptoms here were a low voltage across the battery with the engine running. I checked this a few months ago and it was around 14.7V.

I'll also try disconnecting the traxide kit to see if I get different voltages than I have been of late.

Part of me thinks the low voltage readings will have reduced the life span of the main battery also (it's 2years old now).


Hmmm... :confused:

[drivesafe]

Hi Mijango, 14.7v is ideal and you should not be having any charging problems with that sort of voltage level.

Can you monitor the voltage while driving and see if it stays at 14.7 for any length of time, or if it drops too soon after starting?

[mijango]

Sure Tim. I'll monitor it and see (not sure how I can monitor while driving though. Maybe through the cigarette socket??).
Though I'm not so sure the problem is that the alternator isn't providing adequate voltage, but rather the fact the battery system seems to struggle to hold a reasonable charge for any period of time.

[Blknight.aus]

so dave how does one fix this? Camper batteries will have the fridge load on them when driving/charging.
Cable sizes are fine, same size cables as in his brothers 100 series, all joins are OK. When we were away last I stuck my clamp meter (never go camping without it) on the camper batteries, whilst charging and was getting 6a each into them and the batteries were low, they were charging a lot better with the solar panel.

Recalibrate your "everythings-OK-o-meter"?

theres so manything that could be wrong, any high resistance joint could cause it, a stretched wire could do it, the contacts in the DBS could be shot you could have terminal protectant applied incorrectly and acting as an insultor, if it s a solid state DBS the drive transistors could be shot If its got fuse protection in it or a Circuit breaker they could be Damaged, the fuse might even have blown and is making a partial contact...

I've even seen a fuse replaced with a light

ID ditch the clamp meter at this point and start looking for voltage drops from point to point.

I lie.

Id rip the whole lot out in disgust at not seeing a traxide unit in there and finding the wiring and harnessing to be below the par assiciated with most of installs of that gear.

In the process I'd probably also make the bet that I was going to find some shoctlocks that were going to get ripped out.

[drivesafe]

Hi again Mijango, is that the cranking or auxiliary battery.

In either case, when you are not going to be driving for a a day or so, give the battery a good charge with your ctek then let it sit over night and see if it still looses charge.

[RoverLander]

To answer the original question.....

Its the low voltage version of the Redarc you need. It has an extra wire which you connect to a 12v source that comes on only when the motor is running. Once that wire becomes active the redarc unit knows it can start charging your battery.

If the car decides at some stage to run at 12.2 volts for some time (Which it is designed to do once the main battery has been fully charged) then the LV version of the Redarc will keep charging. The non LV version would stop charging below 12.7v.

The other main thing to remember is to connect the negative of the redarc to the body bolts near the battery. Do not connect to the negative battery terminal.

Ideally your camper trailer should run its own DC/DC charger for its battery.

I have this setup in my MY15 D4 and caravan. In this configuration the car battery management systems and second battery systems are completely separated and cant cause any issues. The car only sees an extra current draw.

Yes all this may cost more and it may take slightly longer to charge your second batteries at times. However they will be fully charged independent of what the car systems a doing.

Peter

[drivesafe]

Hi Peter and your D4 should never operate at 12.2v.

At that voltage level, you would be running so low that you would be discharging your cranking battery while driving, and it is this error low voltage that has been causing problems that requires a software upgrade.

There was only one make of vehicle that ran at that sort of voltage level and that was the Ford Ranger. It caused so many related and unrelated problems that anyone with a Ford Ranger can now have the variable operating voltage program deleted by the Ford dealers. They then run at a constant 14+v.

While a D4 has a very large alternator capable of powering a couple of DC/DC devices, DC/DC devices still pull in huge amounts of current above the much smaller current they provide for the battery they are charging.

This adds an additional fuel cost to the operation of the D4, all for no gain.

[Vern]

Hi Vern, the GU and the 100 have exactly the same charging setup and voltages

That was all I needed to know, dave could have just said that:D
I wired the 100 series, arb did the gu:(

[drivesafe]

Hi Vern and Dave was just trying to point out where the problem is likely to be.

The quickest way to start to check for a wiring problem is, while the batteries in the camper are low, and the tow vehicle's motor is running, measure for the voltage drop in the positive and negative circuits.

To do this simply run a length of thin wire from your cranking battery's positive ( + ) to somewhere close to the camper battery's positive ( + ) terminals and then use your multi meter to measure the voltage difference between the two positive ( + ) terminals.

Then do the same with the negative circuit. Move your thin wire to the cranking battery's Negative ( - ) terminal then go to the camper batteries and measure the voltage difference at the camper batteries Negative ( - ) terminals.

If all is well, then there should be a similar voltage difference on each circuit and the total voltage difference will give an idea in the cabling is too thin.

If there is a much bigger difference in one circuit compered to the other, you have probably found the problem and then have to find the specific cause.

The most common cause of poor battery charging is first, the use of cabling that is too thin, the next most common cause is a bad earth return and in most of these cases, it is because the chassis has been used as the earth return.

[Vern]

From memory tim, the camper batteries were .1v different to the alt output voltage when running. Will re test it all one day.

[Redback]

In all the years I've had the Traxide systems in our cars, we've never had an issue, now 3 vehicles so far and in all 3 vehicals the Traxide system has not only charged the auxillary battery, but prolonged the life of the OEM battery, I got almost 6yrs out of the OEM battery in the D2(2 weeks shy of 6yrs) now 4yrs from the OEM battery in the D4, so when Tim developed one for the Amarok, we got one, so it's coming up to 10yrs now, July/August 2005 to now, not an issue.

Baz.

[drivesafe]

Hi again Vern, I would actually expect to see a much larger voltage drop if the batteries were in a low or even just in a partially discharged state.

I carried out some tests in a D4, using a very low Optima D34 discharged down to 20% ( 11.58v ), connected to the alternator via a 10m length of 6B&S twin ( 13.5mm2 x 2 ) cable and at the beginning of the charge, the voltage drop was well over 1.0v but the battery was drawing up to 63 amps for a short time.

So again, if your batteries are low or just in a partially discharged state, there should be a larger voltage drop.

If you get a chance to test them again, let us know what you find.

[RoverLander]

Hi Peter and your D4 should never operate at 12.2v.


It does this for periods of time. Its part of the fuel saving algorithm that the car uses. The car knows the exact state of charge for the battery. So it may let the battery run down for a while in order to save fuel. When you then coast down a hill it will jump back up to 14.7 and recharge the battery back up.

Its only when we connect electrics directly to the main battery or change the total battery capacity by connecting batteries directly to the main battery does the system have a problem.

I believe that most dealers disable or remove the variable voltage algorithm when they see a second battery system installed in the car.

Peter

[Redback]

It does this for periods of time. Its part of the fuel saving algorithm that the car uses. The car knows the exact state of charge for the battery. So it may let the battery run down for a while in order to save fuel. When you then coast down a hill it will jump back up to 14.7 and recharge the battery back up.

Its only when we connect electrics directly to the main battery or change the total battery capacity by connecting batteries directly to the main battery does the system have a problem.

I believe that most dealers disable or remove the variable voltage algorithm when they see a second battery system installed in the car.

Peter

Somehow I don't think they would, or actually know how too.

[ytt105]

Is it possible to do this via a Nanocom Evo?

Sent from my ThL W8 using AULRO mobile app

[drivesafe]

It does this for periods of time. Its part of the fuel saving algorithm that the car uses. The car knows the exact state of charge for the battery. So it may let the battery run down for a while in order to save fuel. When you then coast down a hill it will jump back up to 14.7 and recharge the battery back up.

Its only when we connect electrics directly to the main battery or change the total battery capacity by connecting batteries directly to the main battery does the system have a problem.

I believe that most dealers disable or remove the variable voltage algorithm when they see a second battery system installed in the car.

Peter

Hi Peter and again, the D4 operating voltage should never get that low.

To draw a battery, particularly one as large as the D4 cranking battery, down to 12.2v would require a huge current draw and then to try to RECHARGE the battery while driving, to get it to a state of charge that would maintain the battery in a reasonable condition is an impossibility.

As has already been posted, if your D4 is operating at 12.2v then you have a software problem.

Furthermore there is no way a dealer can override or change the Variable operating voltage in any Land Rover.

And another point, how would connecting an auxiliary battery to the cranking battery be any different to connecting a DC/DC device or a set of driving lights or a 3 way fridge?????????????

[drivesafe]

Is it possible to do this via a Nanocom Evo?

Hi ytt and at this stage, no, there is no way to charge the Variable Operating Voltage settings.

[RoverLander]

Im regretting getting involved in this discussion.

Other people seem to understand that some cars will operate at low voltage. This from the TJM web site:
=======
Variable Voltage Alternators

Some vehicles released in late 2010 onwards with common rail diesel and petrol engines have variable voltage alternators that are on the vehicle CANBUS. These alternators vary output based on driving conditions at the time. The range of voltage can be between 12.3V and 15V For this reason, the alternator may not charge a dual or multi auxilary battery bank at all times, and may apply too high a voltage for the auxliary battery chemistry type at other times.

Known vehicles with this style of alternator - Nissan Navara D40, R51 Pathfinder 2011 onwards V6 Diesel only. Hyundai Santa Fe 2010 +, Range Rover 4 2011 +, Ford Ranger 2011 +, Pajero 2012 +, Mazda BT-50 2011 + and Land Rover Disco 4, Isuzu D-Max 2012.
=========

I dont know if dealers can override the variable voltage capability. A software upgrade definitely can change variable voltage behaviour.

I believe there is a difference between joining two batteries directly together and letting the car charge them rather than a device drawing a current.

Each to their own. Im happy with my setup. Others are happy with a different approach.

Happy to answer any questions about the DC/DC setup.

Peter

[Tombie]

There's a huge difference between "happy with a setup" and having one that is optimum, cost effective etc..

What "works" doesn't mean it's the best..

DC-DC units would have to be one of the best for meeting an unnecessary "need"

Persons who understand Electrical and Electronic theory certainly wouldn't fit one in this application.

For example - there is no way for the vehicle to detect how large a battery bank is that is fitted to a vehicle - only draw of current.

Handy when a Fuel Polariser is also fitted :) (tic)

[Mungus]

Little bit of confusion going on here.
Drivesafe is correct (as expected) related to the battery getting down to 12.2V. Not good at all for maintaining charge state. Thing is the battery doesn't/shouldn't get down to that voltage.
RoverLander and subsequently others stated 'the car' gets down to 12.2V. What I think he meant to state is in relation to the variable voltage alternator where the alternator voltage output can get down to 12.2V.

[drivesafe]

Hi again Peter and that TJM "info" is vague at best.

For a starter, Variable voltage did not start in 2010, Land Rover had the first 4x4s with Variable Voltage in 2005 and Toyota started in 2008.

Furthermore, only one make had voltages operating down to 12.3v and that was/is the Ford Ranger, and as already pointed out, Ford, for the last 18 months, has given their dealers the option to deactivate their system at the owners request.

While a D4 will not operate down to 12.3v under normal use, in Australia, they will go as high as 15.5v and in the UK, over 16v.

So once again, that info from TJM is not accurate.

Also, can you please explain how two batteries being joined together and the current being drawn by the auxiliary battery is any different from say a set of Fyrlyt driving lights drawing 40 amps from the same system?

[drivesafe]

Little bit of confusion going on here.
Drivesafe is correct (as expected) related to the battery getting down to 12.2V. Not good at all for maintaining charge state. Thing is the battery doesn't/shouldn't get down to that voltage.
RoverLander and subsequently others stated 'the car' gets down to 12.2V. What I think he meant to state is in relation to the variable voltage alternator where the alternator voltage output can get down to 12.2V.

Hi Mungus and your most of the way there.

There have been numerous instances of D4s have a variable operating voltage but run at a constant 12.2v, and this is not the norm.

Now in every instance I have been involved with, the owners have ended up with flat batteries and have had to charge them with a battery charge.

A fully charged battery will have a loaded voltage of no more than 12.7v and as the load increases, the voltage will drop.

So after fully charging their batteries, they find the operating voltage in their D4 is still 12.2v. But the battery can actually be in a higher state of charge but the load being applied to the battery by everything running in the D4, is causing the battery to drop down to the 12.2v, at which point the alternator then maintains the voltage at 12.2v by providing just enough current to compensate the load being applied to the cranking battery.

The problem is that eventually, the cranking battery is still discharged down to 12.2v but by then, the alternator is providing all the current needed to run the D4.

As posted above, at 12,2v, while there may be no load being applied to the cranking battery ( because the alternator is carrying the load requirements ), 12.2v is not suitable for charging or maintaining a lead acid battery.

Ultimately, the condition of the battery diminishes to the point where it no longer holds a charge for any period of time and hence the continual flat cranking batteries.

Toyota went through this same problem yet their lowest operating voltage was 13.2v but this was still to low to maintain the condition of the battery.

About 15 months back, all new Toyotas came with a minimum operating voltage of 13.6-7v.

This slight increase seems to have improved Toyota battery life and charge condition.

Unlike Land Rovers, the low operating voltage of a Toyota is very easily and economically fixed by installing a $50 Alternator Voltage Booster Fuse, supplied by it's inventor in Melbourne.

With Land Rovers, there is a way to get the alternator to run at higher voltages for longer periods, which results in any battery connected to the system, being recharging in a quicker time than when using any device and this is what my isolators exploit.

[SilvaD4]

Happy to answer any questions about the DC/DC setup.

Hi Peter, I will take you up on the kind offer...

I have all the equipment from a 40A RedARC DC-DC system that was neatly installed in my previous ride.
Although it was only installed for 3 months the system worked very well (no issues at all). All batteries were at 100% charge when it was removed.
The next step is to have the same set-up installed into my 2014 D4 SDV6 HSE.
The charger is of the LV variety so it should suit the D4.



So what is the model of your DC-DC charger and where is it mounted?
Are you using a relay kit for the solar?
Where did you mount the charger, the relay and the battery (or batteries)?
Did you add any wiring in the cargo area (extra sockets)?
Any hints as to the wiring routes would also be appreciated.


Thanks in advance,

Jacques

[Nmritchie]

Hi Mijango, my 2014 Disco tows an Ultimate camper trailer which has a Redarc BCDC1225 which keeps the campers batteries well charged while driving and from solar while camped. I also had the Disco fitted out by OL with a 55AH auxiliary battery to run a fridge in the car, and to also charge the auxiliary from solar on the cars roof. The solution was to install a similar Redarc DCDC (LV) charger in the car that is enabled by an ignition wire but also uses the Redarcs voltage sensor on the crank battery to give priority to charge the crank battery first. An ignition relay also enables solar charging via the Redarcs MPPT controller only when the car is parked. Another ignition relay ensures the camper trailer draws on the vehicle only when the alternator is running. The 25amp charger was recommended over the 40amp option to avoid pumping more amps into the auxiliary than is good for it.

In summary, the two DCDC/MPPT chargers look after their respective batteries very well while both work in parallel as loads on the alternator. For me, DCDC with MPPT was the decider, and works great.

Vern, I understood you to say that one DCDC charger is being used to charge both the auxiliary in the car as well as the camper trailer's batteries. That will not work. When any "smart" charger is connected to multiple batteries, they must be the same type, capacity and state of charge. Ie have the same loads, and cable lengths/resistance in their parallel wiring. Otherwise the charger's algorithms cannot properly decide based on the "battery" voltage when to activate boost, float or any other charging state.

Also see Collyn Rivers books or this summary
Solar Power @ ExplorOz Articles (http://www.exploroz.com/Vehicle/Electrics/Solar.aspx)

I hope that helps.
Neil

[LRD414]

We tow an Ultimate and given all modern vehicles have a lazy alternator, hence the invention of DC chargers to compensate for that little design fault, and to overcome that we simply but a RedArc BMS in the Ulti and that resolves the lack of volts coming back from the car via the Anderson plug. If you rely just on volts via Anderson plug camper batteries will not be charged.

I have a Traxide D4-5S kit, which includes the heavy duty cable to the rear complete with Anderson plug that I use for multiple duties; eg running tyre compressor etc. or connection to solar panels (via MPPT) to charge the yellow top or to charge camper batteries while driving or to use a 240V battery charger when at home.

So I thought this was a good setup to charge the 2 x 100A gel sealed batteries on the camper while driving, which are directly connected via a Anderson plug and 50A CB. When camped, I use the plug to connect solar panels (via MPPT). But I have no BMS on the camper, only a 240V charger not used while driving or on trips.

Perhaps assuming I have a good setup was wrong based on RobA's highlighted comment re low volts coming from vehicle?

But I've had a cig plug volt meter reading over 14V when vehicle running at both the front sockets (cranking battery) and rear sockets that come with Traxide kit (aux battery) and I thought this was good voltage for charging the camper batteries while driving, assuming similar volts via Anderson plug? Happy to be corrected if wrong.

Regards,
Scott

PS ... sort of a hijack of OP but just trying to increase my knowledge. I do get a bit lost sometimes with this stuff. The camper is quite new, so no actual experiences with using the car to charge batteries up from a low SoC.

[drivesafe]

The camper is quite new, so no actual experiences with using the car to charge batteries up from a low SoC.
Hi Scott and you will have no problems with charging low house batteries while driving.

It's not just my isolator that improves charging, your alternator has the unique advantage of adjusting it's current output for different loads.

So when your house batteries are low, your alternator will provide a much higher current, thus enabling your house batteries to charge faster.

This is something no DC/DC device can do.

[SilvaD4]

So when your house batteries are low, your alternator will provide a much higher current, thus enabling your house batteries to charge faster.

Just wondering, will this higher current output from the alternator also go to the terminals of the main cranking battery?

[THE BOOGER]

The voltage will be seen at the cranking batteries terminals but the amperage will go to the lowest SOC batteries:)

[Blknight.aus]

Depends on how you've got the batteries wired up.

ALternators output ramps to suit the load up to the maximum output of the alternator then the voltage drops off and the amps keep going up. this is what most DC-DC chargers cant do, they hit their max out put and stay there. This is where the traxide systems in 95+ percent of cases outperfrom dc-dc systems.

The next paragraph is the really really simple version of direct wired charging for batteries in parallel, the actual flows are a lot more complicated than the simple on/off examples Im using.

The output of the alternator goes to where its needed, if you've got a flat battery and a fully charged one the power flows into the flat battery. If the alternator is hooked up to the fully charged battery and your second battery is hooked up to the fully charged battery then it goes past but not into the fully charged battery. If you have the alternator setup between the 2 batteries then the power doesnt flow towards the charged battery until the flat battery has charged up and both batteries are at the same level of charge. At this point the output of the alternator splits between the 2 batteries equally. Once the batteries are charged then the amps of the alternator drop off to cover just the electrical loads.

If the flat battery is down low enough you'll actually have some amps coming out of the fully charged battery going to the flat battery.

Lets say that your fully charged battery is not the vehicle battery but its the aux battery. lets say the main battery is a little low.

A traxide unit will, within certain limits depending on the unit you get, allow the aux battery to put amps into the vehicle battery. The upshot of this is if you have some sort of charging system hooked up to your aux battery that will then permit you to charge both batteries at once.

I'm not currently aware of a DC-DC charger that will permit that to happen and theres not to many DBS systems that will either.

[drivesafe]

Just wondering, will this higher current output from the alternator also go to the terminals of the main cranking battery?

Hi Silva, and I am not quite sure what you want to know and Booger and Dave have covered it pretty well but I will give you some working examples and these are crudely explained examples.

Let say you have a standard D4, with no form of dual battery system fitted and you have been driving for a few hours, so your cranking battery should be fully charged.

As you are driving along, your D4 will need around 40 amps of power just to meet it's own electrical requirements.

So in this situation, there is a 40 amp draw being applied to the alternator and this current flow is being supplied to the vehicle via the positive ( + ) terminal on the cranking battery.

The Positive ( + ) terminal is being used as a distribution point for the positive power circuit in your D4.

NOTE, because the cranking battery is full, the is no flow of current into the cranking battery and no flow of current coming out of the NEGATIVE ( - ) terminal of the cranking battery but more on this later.

Next situation. You have just started your D4 and as you drive off, the cranking battery draws say 5 amps to replace the energy used while starting your motor.

This time there is a 45 amp draw being applied to the alternator and the 45 amps is supplied to the cranking battery's positive ( + ) terminal.

Again, 40 amps goes on the power the D4's own requirements but 5 amps flows into the cranking battery via the positive ( + ) terminal and 5 amps comes from the cranking battery via the negative terminal.

As the cranking battery charges, it's current demand reduces, so the amps flowing through it reduces.

Now for a dual battery type situations.

You have been camping for a few days and with my isolators, you will have been drawing power from both the cranking battery and the auxiliary battery.

Lets say you have drawn the maximum available capacity from both batteries, with your Cranking battery at 50% SoC and your auxiliary battery at 20% SoC.

This time, once you start driving, there will be a 40 amp draw for the D4's electrics, around as much as an 80 amp draw for the Optima and another 30 amp draw for the cranking battery.

Thats a total of around 150 amps being applied to the alternator.

This time, around 150 amps will be provided by the alternator at the cranking battery's positive terminal. 120 amps will flow passed the terminal and on to the auxiliary battery and the D4's electricals. But 30 will be drawn through the cranking battery. And note there will be an equal 30 amp flow from the cranking battery's negative terminal.

As both batteries charge, the current draw will quickly decrease.

Note, the only current monitoring the D4 can do is the current that flows through the earth lead connected to the cranking battery's negative terminal.

The EARTH RETURN for all other devices is by the body, chassis and the motor itself. Not via the cranking battery's negative lead.

So no other current is monitored or where that current is going to. So claims that there is some sort of special current and/or voltage going to an other battery and the alternator knows about it, is just mythical.

[clubagreenie]

The 25amp charger was recommended over the 40amp option to avoid pumping more amps into the auxiliary than is good for it.Correct me if I'm wrong Tim but the charge will only supply to demand, not pump out to it's max capacity hoping that whatever's connected will deal with it. Just as you can use a higher amp but same voltage output phone charger than the std one. The phone will only draw whats needed, the excess is just ether. But a lower amp rated charge would be damaged due to the excess draw of the device.

[drivesafe]

Hi Clubagreenie, this is one of the problems with the marketing they use to flog DC/DC devices. They try to scare people into thinking that they will destroy a battery if they use the alternator as the charging device, falsely claiming that the unlimited current of an alternator will damage the battery.

You got it spot on, the battery itself with govern the amount of current you can charge it with.

NOTE there are a large number of STANDBY type AGMs that have a charge current limit, but most of these types of batteries also suffer from heat found under the bonnet, so they have to be fitted somewhere else.

By fitting these batteries elsewhere, the long cable run becomes a quasi voltage/current regulator and the batteries again self regulate.

We are in the D3/D4/RRS section of the forum and as such, 99% of these vehicles will have an Optima D34 Yellowtop battery as their auxiliary battery.

The Optima D34 Yellowtop battery is a genuine AUTOMOTIVE GRADE AGM, specifically designed to tolerate the harsh conditions found in a engine bay.

These batteries also have NO CHARGE CURRENT LIMIT, and can and will take everything the alternator can produce.

This means if the auxiliary battery was in a very low state, it could easily and SAFELY draw 90+ amps while recharging as you drive.

As these sort of charging currents are only available from an alternator, makes 25 and 40 amp DC/DC devices look like jokes, which in this case they are.

[Blknight.aus]

Correct me if I'm wrong Tim but the charge will only supply to demand, not pump out to it's max capacity hoping that whatever's connected will deal with it. Just as you can use a higher amp but same voltage output phone charger than the std one. The phone will only draw whats needed, the excess is just ether. But a lower amp rated charge would be damaged due to the excess draw of the device.

pretty close, close enough that it cant be corrected in laymans terms.

The other reason that most places prefer to sell the 25 amp units is the cost of the installation and the quality of workmanship they can get away with.

Most cheap auto stuff has a limit of between 20 and 30 amps, anything over needs specialty connections which cost more to buy and you need to use thicker wire which is unecenomical to buy in small quantities and wastefull to buy in large volumes to get the price per meter down if your not going to use it.

[RoverLander]

Hi Peter, I will take you up on the kind offer...

I have all the equipment from a 40A RedARC DC-DC system that was neatly installed in my previous ride.
Although it was only installed for 3 months the system worked very well (no issues at all). All batteries were at 100% charge when it was removed.
The next step is to have the same set-up installed into my 2014 D4 SDV6 HSE.
The charger is of the LV variety so it should suit the D4.


So what is the model of your DC-DC charger and where is it mounted?
Are you using a relay kit for the solar?
Where did you mount the charger, the relay and the battery (or batteries)?
Did you add any wiring in the cargo area (extra sockets)?
Any hints as to the wiring routes would also be appreciated.
Thanks in advance,

Jacques


Jacques,

I have had a MY10 D4 and now a MY15 D4. I have learnt some things which I used to refine the installation of the DC/DC charging in the MY15. Answers to each of your questions below:

MODEL:

MY10: Redarc BCDC1220. Note: LV models did not exist back then. I experience initial problems asthe installer had wired the negative wire directly to the car battery rather than to the body earth. Once I moved the wire the charger worked fine. That carnever went below 13.2V.

MY15: Redarc BCDC1225LV. This has the Low Voltage switch wire. It is also a solar MPPT charger.The MY15 will run for periods of time at around 12.2V and so it needs the LV version. Note it doesn't run around at 12.2v for long period of time (I haven't measured the time it will stay at 12.2v).

SOLAR RELAY:

MY15: No solar relay. My DC/DC charger is mounted on the battery box in the rear of the cargo area behind my fridge. We have this in the car 95% of the time. A cable runs from the Main Battery down along the driver's side door channels and ends in an Anderson Plug. The DC/DC charger input cables also have an Anderson Plug. Normally the car battery power and DC/DC charger Anderson plugs are connected. When I want to use solar charging I just unplug the Anderson Plug and Plug in my portable 150W Solar panel. Make sure you bypass any Controller on your solar panel as the Redarc will manage the solar charging. Its a much better MPPT charger than installed on most solar panels.

WHERE:

MY10: This was installedby a 4x4 accessory store familiar with Land Rovers. The battery and Redarc were mounted under the bonnet between the Main Battery and the Coolant/WasherBottles. A battery tray was mounted there. I could only fit a 55AH battery there and I thought this may not be enough. So I had a second 55AH battery mounted in the rear cargo area. Thick cables were run between these batteries.

While it all worked well for 4 years, I was not happy with this install as the batteries would be at different temperatures resulting inthe battery in the engine bay being potentially overcharged. The rear battery may not have been fully charged at the end of the cable run. I was also concerned that the high engine compartment temperatures may cause the DC/DC charger to downrate itself so it didn't overheat although I don't know if it ever did.

MY15: I have one 100AH AGM battery in the rear cargo area (as described above). This is secured to a shelf and cargo barrier system. The DC/DCcharger is mounted on top of the battery box. This way there is minimal distance between the charger and the battery. The DC/DC charger is in a cool area of thecar so will charge at full rate.

WIRING:

I have a Merit and cigarette lighter plug in the Cargo area for the fridge. I have another cable running to the UHF radio under the driver's seat. I have a two USB charger socket also in the rear cargo area. All this runs off the 100AH battery in the cargo area.

One large cable to handle 50amp runs from the car battery to the DC/DC charger. Note that the negative is connected the ground post in front of the car battery compartment (NOT DIRECTLY TO THE BATTERY!) The cable runs across the back of the engine compartment, through the firewall grommet on the driver's side and then along the floor channels and pops out at the rear of the driver's side rear door.

You also need to find an ignition active cable. We picked one up from the trailer plug at the back of the car. We were doing other wiring in that area as we were installing a Redarc TowPro at the same time.

If you are installing your battery in the cargo area the please ensure it is a fully sealed battery (to avoid potentially dangerous gases in the car interior). Read the Redarc instructions to ensure you connect up the other wires to correctly set the charging Algorithm of the DC/DC charge to match the type/chemistry of battery you use.

OTHER:

I note that you have the 40 Amp DC/DC charger model. I suggest that you check your second battery manufacture's web site to determine the maximum Amperage your battery can accept. Not all batteries will accept a 40Amp charge.

I have a voltage monitor for the main car battery and the GME Radio display shows the voltage for the Second Battery. This is a handy way of keeping an eye on things.
I have a second set of heavy cables running to an Anderson plug near the TowBar. This connects to another Redarc DC/DC Charger in the caravan to charge 2 x 120amp batteries.

BENEFITS:
Independent and 100% charging of all the batteries.
Correct charging foreach battery chemistry.
Not effected by differences in battery temperatures.
You can charge from a solar panel.



Yes it costs a lot but I use the car and equipment and I want it to work at its optimum.



Peter

[SilvaD4]

Thanks Peter, a most informative post. Having done this twice (2010 D4 and later in a 2015 D4) has allowed you to iron out the bugs very nicely.

Yes, my 40A DC-DC charger is way to big for my batteries. However my son has a 20A LV version in his Prado (and a larger aux battery set up) and he has expressed an interest to do a swap.

Jacques

[Wheelan]

Hi Wheelan here is the thing, with your system and your 100Ah battery, you had 80Ah available if you discharged your 100Ah down to it's safe limit of 20% SoC.

If you had one of my isolators, you would have had 125Ah available.

But even if you still only used the same 80Ah, then the two batteries in my system, your auxiliary and your cranking battery, will only be discharged down to about 60% SoC and this means your batteries would be fully charged in a shorter drive time than your single 100Ah battery could be with or with out your DC/DC device.

The recharge time in a D4 is even quicker with one of my isolators fitted.

Then add the fact that with short driving trips around town and my system will actually keep your cranking battery in a higher state of charge, something no other system can do.
My thing is I am a bit old school and want to keep my starter battery for starting, and possibly winching if required the next day. I also feel my second battery has never been in better shape when properly charged from a proper 5 stage charger. Both systems have their merits, I actually dont need any more battery power than what I have already, 2 spares in the CT as well as the one in the car keeps everything going for a long time.

[SilvaD4]

The Optima D34 Yellowtop battery is a genuine AUTOMOTIVE GRADE AGM, specifically designed to tolerate the harsh conditions found in a engine bay.

These batteries also have NO CHARGE CURRENT LIMIT, and can and will take everything the alternator can produce.

Out of interest I have pasted the below info from Optima on the D34

"Model: D34
These batteries are designed for starting and deep cycling applications and for use in vehicles with large accessory loads.

Recommended Charging Information
Alternator: 13.65 to 15.0 volts
Battery Charger: 13.8 to 15.0 volts; 10 amps maximum; 6-12 hours approximate
Float Charge: 13.2 to 13.8 volts; 1 amp maximum (indefinite time at lower voltages)
Rapid Recharge (Constant voltage charger): Maximum voltage 15.6 volts. No current limit as long as battery temperature remains below 125?F (51.7?C). Charge until current drops below 1 amp.
Cyclic or Series String :14.7 volts. No current limit as long as battery temperature remains below 125?F (51.7?C). When current falls below 1 amp, finish with 2 amp constant current for 1 hour.
All limits must be strictly adhered to."

Food for thought....

[THE BOOGER]

Yes rapid recharge and cyclic recharge as stated is no current limit in the doc you posted:) note the limit put on chargers though

[drivesafe]

BENEFITS:
Independent and 100% charging of all the batteries.
Well I would like to know how you know your battery is at a 100% charged state. Short of removing the battery and taking it to a laboratory for testing, there is NO WAY the determine if a battery is at a 100% state of charge while the battery is in a vehicle.

So that one is an advertising myth.

The industry standard is that any battery that is over 95% is fully charged.



Correct charging foreach battery chemistry.
Yep this is a big problem when using a DC/DC device to charge batteries. You MUST have the same type of batteries if using one of these new DC/DC device to charge them.

Another one of these advertising myths.

If you let the alternator do what it has been doing for many decades, it will easily and CORRECTLY charge any mix of battery types and sizes with out any problems at all.



Not effected by differences in battery temperatures.
Neither is charging by an alternator.

So once again another advertising myth



You can charge from a solar panel.

NOT AT THE SAME TIME.

So I am not sure how you think this is a benefit???????

Whereas, if you are towing a caravan with solar on the roof, you only need a solar reg in the caravan ( which you will need anyway ) and you can be charging ALL BATTERIES from the alternator and solar at the same time.

So in a nut shell, charging from an alternator is far more beneficial and a hell of a lot cheaper to setup AND OPERATE

[drivesafe]

My thing is I am a bit old school and want to keep my starter battery for starting, and possibly winching if required the next day. I also feel my second battery has never been in better shape when properly charged from a proper 5 stage charger. Both systems have their merits, I actually dont need any more battery power than what I have already, 2 spares in the CT as well as the one in the car keeps everything going for a long time.

Hi Wheelan and as the operating system of my isolators has been around for more than 25 years now, I reckon that makes it OLD SCHOOL technology but my old school technology is still proving to be FAR SUPERIOR at charging batteries than any of these NEW wonder devices.

As for using a 5 stage charger goes, well thats a pretty simple way to charge lead acid batteries when you could be using something like a charger with an INFINITE number of charge stages, you know like how an alternator charges.

The problem with battery chargers, DC/DC devices and Solar regulators is that they are trying to copy what an alternator does, and does naturally, but battery chargers, DC/DC devices and Solar regulators are constant CURRENT charging devices and this is a major limitation for these devises.

Whereas, an alternator is a constant VOLTAGE type charger and constant voltage type charging is FAR SUPERIOR when it comes to charging lead acid batteries.

For example, when was the last time you heard of an alternator cooking a battery. It does not happen. But it is a common occurrence with both battery chargers and DC/DC devices.

Battery chargers and DC/DC devices just can not compete with how well an alternator works at charging batteries.

Now to your winching operation. It is known in the industry that there is a huge advantage to connecting two batteries together while winching.

Using one of my USI-160 isolators, you not only get the advantage of shearing the load while operating accessories but you get the huge advantage of linking batteries together while winching.

A win-win setup.

[drivesafe]

Out of interest I have pasted the below info from Optima on the D34

"Model: D34
These batteries are designed for starting and deep cycling applications and for use in vehicles with large accessory loads.

Recommended Charging Information
Alternator: 13.65 to 15.0 volts
Battery Charger: 13.8 to 15.0 volts; 10 amps maximum; 6-12 hours approximate
Float Charge: 13.2 to 13.8 volts; 1 amp maximum (indefinite time at lower voltages)
Rapid Recharge (Constant voltage charger): Maximum voltage 15.6 volts. No current limit as long as battery temperature remains below 125?F (51.7?C). Charge until current drops below 1 amp.
Cyclic or Series String :14.7 volts. No current limit as long as battery temperature remains below 125?F (51.7?C). When current falls below 1 amp, finish with 2 amp constant current for 1 hour.
All limits must be strictly adhered to."

Food for thought....
Here is some more food for thought, when using an alternator to charge Optima batteries, you will NOT exceed ANY of the limitation set for these batteries.

So mate, sorry but I don't get your reasoning for making that statement?

For example, two and a half years ago, my wife's Toyota Seca's battery died so I put an Optima D34 Yellowtop in to replace it till I got around to replacing the battery.

About 2 months back I finally had to charge the battery because the Optima died.

It was 7.5 years old when I put it in the Toyota, making it 10 years old when it died.

It had been in my D3, then my D4, then my Range Rover, then is sate in the work shop for nearly a year and in the ten years I had that battery it was only ever charge by a battery charger on about three occasions.

So charging straight off the alternator really shortens the life of these batteries NOT.

[drivesafe]

If you are installing your battery in the cargo area the please ensure it is a fully sealed battery (to avoid potentially dangerous gases in the car interior).
A couple of other points, there is no such thing as a fully sealed lead acid battery and if you check, most lead acid batteries are now marked as "SPILL PROOF", not "SEALED" and as a DC/DC device can cook a battery, while an alternator will not.

So you are far safer charging a lead acid battery, mounted in the cab of a vehicle with an alternator, not a DC/DC device!!!


MY15: I have one 100AH AGM battery in the rear cargo area (as described above). This is secured to a shelf and cargo barrier system. The DC/DCcharger is mounted on top of the battery box. This way there is minimal distance between the charger and the battery. The DC/DC charger is in a cool area of thecar so will charge at full rate.

For less money, you could have fitted one of my Triple Battery systems, which simply mounts two Optima D34 batteries in the engine bay.

This would give you more available space in the cargo area.

It would also give you more usable capacity. 80Ah with your system and around 125Ah with my system.

It would save fuel.

But the biggest advantage is that with your setup and a low battery, it will take 5 hours of driving time to fully recharge your battery, mine will fully recharge the two Optimas in less than 90 minutes.


Now if you only need that 80Ah that you have, you could still have fitted one of my standard dual battery systems, with a single D34 Optima battery.

You would then have had around 90Ah available instead of your 80Ah.

The setup would have been heaps cheaper than the one you have.

You would still fully charge the optima in under 90 minutes.

My setup is lighter and therefore you save even more fuel.

Both my standard and triple battery systems look after the cranking battery as well as the auxiliary batteries, your is only looking after your auxiliary battery.


I'm sorry mate but I just can't see how you, and the others, think that you have better systems when they all have so many inherent drawback.

Your logic just does not make sense

[Homestar]

In the 101 I run 1 x lead acid cranking battery, 1 x 100AH deep cycle battery and then when towing the van, that has a 90AH Calcium battery in it (that I had lying around). 99% of the time they all stay connected. I'll manually switch the starter battery out of circuit if I'm going to be camping in 1 spot for several days and I know I won't be starting the car. All charge off a half knackered 55amp alternator when driving along (I can tell how loaded the alternator is by the note it 'sings' at :D ), and all stay fully charged. I do have a solar panel mounted on the roof of the 101 and you can see by the status LEDS's on the regulator that it stops working when the car starts as the alternator has bought the bus voltage up high enough. When I stop after a couple of hours, the solar doesn't kick in until I turn a load on and I know through checks I've done that everything is fully charged.

Each battery only draws what it needs so battery type - and using a different mix of batteries, etc is irrelevant.

IMO, save you dollars for something useful - the cars alternator is all you need.

[DiscoMick]

Good advice on this thread. From my limited experience I'd say if your D4 is running properly you should not need a DC-DC charger in the vehicle, as others have said. Sounds lke your smart alternator is saving power and not charging so get the software update Drivesafe mentioned. Our Defender makes 14 volts all the time while the engine is running. It has a Traxide dual battery system fitted.
Where a DC-DC could be useful is in your camper to bump up the charge to the trailer battery while attached to the operating vehicle after the current has travelled all the way down through the trailer plug.
When I researched them the Matsons were much cheaper than the others and do a similar job. They were recommended on a caravan site. They can be either able or not able to take direct solar. That didn't worry me as I already had solar plugged directly into the trailer Anderson plug. Ours bumps the charge to 20 amps and the AGM is happy with it.
Hope that helps.


Sent from my GT-P5210 using AULRO mobile app

[shanegtr]

I brought my D3 with a 40A DC/DC charger setup already installed. While it does an ok job of keeping the aux battery charged, I plan on replacing it with a traxide unit - one day when I have some free coin to do it or sooner if the charger hurrys up and ****s itself

[Mick_Marsh]

Where a DC-DC could be useful is in your camper to bump up the charge to the trailer battery while attached to the operating vehicle after the current has travelled all the way down through the trailer plug.
Oddly, even then it's not necessary.

[clubagreenie]

Thats what i thought. If the current has dropped at that point how is a device that is at the same point in the line getting enough current to provide more.

Oh I forget, thats part of the dc/dc magic is it?

[Redback]

Oddly, even then it's not necessary.

I have this setup in the camper for when we are travelling, it's left over from when we had an Explorer with no dual battery system, I left it in place waiting for it to die after we changed vehicles(D2)

Now we have the D4 I can hook up the anderson plug we have in the rear from our Traxide setup, when we got the D4, I installed the USI-160 that incorperates charging the battery in the camper, as well as the winch and 3rd battery option.

It was only on when the ignition is on, something we needed when we had the Ford, although it works OK, charging via our solar panel works better, and in most cases I will bring it out to fully charge the battery in the camper, also if it's dark, I will set up a 240v charger via an inverter connected to the Auxillary battery, as it also works better, I then turn that on before going to bed.

Only problem this thing won't die, I've shorted it out, got it wet, accidently dropped things on it, it's a bloody tough little thing.

Baz.

[THE BOOGER]

Thats what i thought. If the current has dropped at that point how is a device that is at the same point in the line getting enough current to provide more.

Oh I forget, thats part of the dc/dc magic is it?

No magic to provide 13.8 volts at 20 amps they draw 30 amps from the wiring at the camper end :)

[clubagreenie]

THATS why it takes longer. It has to wait for the camper to charge from the altbto supply the 30 amp to the converter to push the 20amps back.

[THE BOOGER]

Most people who support DC DC chargers just ignore or are not aware of how inefficient they are;)

[drivesafe]

I actually fell very sorry for people who get sucked in to buying DC/DC devices.

I mean that in a genuine way.

They have been fed a truck load of horse do-do, convincing them that they need one of these "wonder" devices or they will end up damaging their batteries.

The reality is that these Wonder devices have only been around for a very short time but RVers have been successfully charging their auxiliary and house batteries for many decades, using nothing more than their alternator.

There are VERY FEW vehicles that actually benefit from these wonder devices but when you read all the B/S advertising, you would think people have never been able to charge their batteries until these wonder devices came along.

The Advertising B/S does not match reality.

There are now so many people, who while on a trip, for one reason or another, have had to remove their DC/DC device, initially for just a short time, till they could repair or replace it, only to find their batteries were being fully charge just as well and in many cases, even better than when they were being charged with one of these wonder devices, and so they never use them again.

There are just a couple of vehicles where a DC/DC device is needed, and as posted earlier in this thread, one is/was the Ford Ranger but Ford now has a fix for their low voltage operations.

Land Rovers have never needed this crap to be able to fully charge any number of auxiliary and/or house batteries, they are just not necessary.

The biggest single selling point for these wonder devices is not the alleged benefits they are supposed to offer, it is the profit margins the sellers get, over what they would get if selling other types of DBS.

And thats it in a nut shell.


Now back to the OP. He has a problem somewhere in his system, and once that is sorted, he will have the BEST dual battery system available for a Land Rover.

[shanegtr]

The biggest single selling point for these wonder devices is the profit margins the sellers get, over other types of DBS.


I know where you are coming from with that statement. When I went digging into my D3 to find out what sort of duel battery system was in place when I brought it I promptly done a quick google search for the unit. I was surprised to find just the DC/DC charger itself was retailing for over $700! I'll probably keep it however once its done its job in the D3 as a solar regulator as it can apparently do that as well. That's if I ever get solar panels.........

[clubagreenie]

Tim,

Your previous "seller" who poo pooed your USI-160 in my D2 and tried to sell me a DC/DC without even asking had another brand vehicle in where the DC/DC was fitted and the mismatched batteries had caught fire. No insurance as the wiring was not up to standard for current delivery and not connected correctly for different battery types.

[mijango]

Thanks to everyone for their comments.. certainly some interesting debate about which system works best, and making me have a think about the true cause of the low voltage problems, before jumping down the path of getting a DC-DC setup.

So, I have done a bit more diagnosis and have found:
a) prior to charging the traxide isolator was flashing with main battery at 11.9v
b) following repeated charging cycles from my CTEK 5.0 multistage charger, I'm seeing the max voltage get up to 12.8v, though fairly rapidly (about 1-2hrs) deteriorate to 12.4v once removed from charge (and the vehicle just sitting their). Note at this stage I have not deconnected the Traxide DBS so this voltage is across both batteries.
c) the alternator is cranking out a healthy 14.2V when the vehicle is running.

Based on this analysis, my feeling is that either:
1. there is something drawing current from the vehicle (or some poor connections somewhere)
2. the cranking battery needs replacing

So, I'm thinking of further testing the system by charging both batteries up to 12.8v again, then disconnecting the batteries manually and the DBS and watching how each battery voltage changes.. well, drops.. over time.

I guess another question, is what sort of voltage should I be expecting from normal operating conditions across the main battery? It was replaced under warranty about 1.5 - 2years ago

[drivesafe]

Hi mijango, from what you have posted, my guess is that it's your cranking battery.

BUT.

There can be a number of reasons for your battery voltage dropping and at the now 12.4V, your battery is at 80% SoC.

The maximum charging voltage you posted, 12.8v, while charging, is not correct for a fully charged battery while being charged.

You should see at least 13.5v, before disconnecting the charger.

At 12.8v, your battery was still being charged, and this can take some time, many hours.

One of the primary causes of low battery states, is the shopping trolley syndrome. Lots of short drives.

These short drive not only stop the battery from being fully charged but they progressively cause the battery's condition to diminish.

The initial problem is that the battery is hard to fully charge and ultimately, it will die an early death.

The charging you are doing can help, but if you have the time, try fully charging the battery then leave it on the charger, in float mode, for 8 to 10 hours.

Then disconnect the charger ( just turn it off will suffice ) and let the battery settle for around 12 hour and then repeat the charge/float cycle.

Do this as many times as is convenient to your needs and then see if the battery has improved.

NOTE, your can use the charge/float conditioning of the battery even when you need to drive the vehicle every day. Just charge/float every night.

The charge cycle charges the battery capacity that can be charged, but the float cycle helps to reverse sulfation of the battery's plates, which in turn over a period of time, actually increases the battery's chargeable capacity.

The conditioning of the battery is actually more beneficial than just charging it.

BTW, you do not need any special form of charger. Any three stage charger, dear or cheap, will condition a battery when used as described.

After you have carried out a few charge/float cycles, try removing the negative terminal from both batteries and let them sit over night.

Measure the voltage in the morning, but don't be surprised if the Optima has a higher voltage reading. This is normal

[mijango]

Thanks for the response Tim.
In terms of charging, I probably should have clarified that I have been conducting full 24hr charge cycles (usually 12-14h charging, followed by letting 10-12h rest and repeat) as you advise (think I actually read this in one of the previous posts). Furthermore, each time I have taken off the charger, it has been in float mode.
Still though, the main battery is only reaching 12.8v, not the 13.4v you mention.
Re your comment that you'd expect the Yellow Top battery to retain a higher voltage than the cranking battery after charging, is this because you (And I) expect the main battery is in a poorer state of health, or down to the characteristic of the battery? Or - to put it another way - if I did the same test with 2 spanking new batteries (1 yellow top; 1 land rover std main) would they both hold charge at the same (or very similar) rates?

[drivesafe]

Hi again mijango, under normal use and testing, you would not disconnect the negative terminals of either battery and as such, the chart I posted up earlier in this thread would give you a fairly accurate indication of the two batteries state of charge.

But while the batteries are connected to the vehicle, they will have a load on them, even if it is a very small load, it is still a load and the chart is for loaded voltage measurements.

By disconnecting the each battery's negative lead and leaving the batteries overnight before testing, you are now testing batteries in an OPEN CIRCUIT situation.

if your cranking battery is still fully charged, it's voltage should be somewhere around 12.7 - 12.75v. This is the same voltage for most lead acid batteries in a fully charged OPEN CIRCUIT state

Whereas the Optima should has a fully charged OPEN CIRCUIT voltage of 13.1v.

This is why you should get different voltage readings.

I meant to mention that after getting the OPEN CIRCUIT voltage reading for your cranking battery, you then need to reconnect the negative lead and take another reading with your ignition on, but not with the motor running.

If your cranking battery is good, you should see 12.7v in the OPEN CIRCUIT state, and about 12.4v and no lower with the ignition on.

Alls well with your battery if the above is what you get.

If the OPEN CIRCUIT voltage is less than 12.4v, before you put a load on the battery, you more than likely have a battery on it's last legs, and when you put a load on it, it will drop much lower.

The reason for disconnecting the batteries, is so if there is something in your D4 draw power with the ignition off, it will have no effect on the disconnected batteries.

So this test should rule your cranking battery in or out as the problem.

With all the charging you have already done, I suspect it will still be a dud cranking battery.

[SilvaD4]

Any thoughts or advice much appreciated.. :)

Hi mijango,

Today I bumped into this website (see link below) and upon reading I thought it would of help to those on this thread as well as the broader LR community.

So I posted it on D3 /D4 / RRS as a new thread. However it got moved to the technical forum because is was not D3 /D4 / RRS specific.
So I have re-posted it here just for your info.

The info on this site was only recently updated (3rd May) so it may have new info for those who have "been there done that".

Design Guide for 12V Systems (http://outbackjoe.com/macho-divertissement/macho-articles/design-guide-for-12v-systems-dual-batteries-solar-panels-and-inverters/)

[THE BOOGER]

Most of what he says makes sense I do see he does not use DC DC chargers himself seem to agree with most of what has been said in this and other threads about the same topic:)

[discotwinturbo]

After being involved with 4WD's with duel battery systems for more than 35 years, I had always used bulk chargers.

Up until about 8 years ago I got tired of short life cycles with deep cycle batteries.

A client, a battery developer, told me the reason for my battery failures was due to uncontrolled amperage going into my deep cycle batteries, in particular agm's. I did swap to orbitals for a couple of years, but for my type of camping and touring they simply did not hold on as long as a larger capacity agm (for the same size).

My batteries were dying prematurely due to them sucking more current into them, then they were designer to draw...not so for the orbitals which could have current smashed in heavily.

I have had no battery failures since using my 20amp redarc, and use another redarc in my camper (actually last 3 campers).

I will never be swayed to go back to bulk chargers.

Brett...

[THE BOOGER]

If your saying your alternators were providing unregulated amperage? then they had a problem with the regulator, a properly working alt will not provide unregulated voltage or amperage.

[drivesafe]

Hi Brett and from the little info you have posted about your use, it would still appear that your use of the batteries is your problem, not the way you charge them.

No one I know has battery problems the way you have posted up that you have, unless they are abusing their batteries or have the wrong batteries for the type of use.

And a DC/DC device will not solve improper use.

[Homestar]

After being involved with 4WD's with duel battery systems for more than 35 years, I had always used bulk chargers.

Up until about 8 years ago I got tired of short life cycles with deep cycle batteries.

A client, a battery developer, told me the reason for my battery failures was due to uncontrolled amperage going into my deep cycle batteries, in particular agm's. I did swap to orbitals for a couple of years, but for my type of camping and touring they simply did not hold on as long as a larger capacity agm (for the same size).

My batteries were dying prematurely due to them sucking more current into them, then they were designer to draw...not so for the orbitals which could have current smashed in heavily.

I have had no battery failures since using my 20amp redarc, and use another redarc in my camper (actually last 3 campers).

I will never be swayed to go back to bulk chargers.

Brett...

Hi Brett, what sort of lifespan were you getting from your batteries before fitting the redarc?

And - as a general question to anyone - what sort of life would you expect out of your batteries?

Obviously how the battery is used and what SOC it is drawn down to between charges also plays a big factor here.

Personally, I get around 5 to 8 years from a cranking battery, and the top shelf deep cycle i've got is now 3 years old. It's the first time i've bothered getting something decent as most of the time I have used old sealed lead acids that I get from work. Used to get 18 months to 2 years out of a half shagged one of those, but I used to dump them as soon as they showed signs of slowing down. I run a 38 litre Engel and a few lights off my system, and I've never seen voltages drop below 12.2 (no load) on my system, usually a lot higher, and most days when camping my solar panel can get them back to almost 100% most days unless it's crap weather - which is the only time the batteries drop below 12.4

Interested to hear everyones experience on this point.

[Redback]

I would expect a minimum of 4 to 5yrs Gav, although with the type of vehicles the D3/D4/RRS are, maybe 4 to 5yrs is about as long as you will get, our D4 is a July 2011 build, so it's coming up to 4yrs in July.

We are on our second battery in the camper, we got almost 8yrs from the first one, the camper is 11yrs old, so I would assume the same from the second one, I have not been relying on the DC-DC charger in the camper to keep it charged fully, it is charged at home before we go away, then when we stop, we pull the solar panel out to keep it charged, basically the DC-DC charger is just to have charge to the battery when travelling, I could just remove it really, as it's purpose is null and void and really serves no purpose now, our Traxide unit could do it better anyway.

I am fixing a few electrical items in the camper at the moment, I think I found another job to do this weekend:o

Baz.

[clubagreenie]

My batteries were dying prematurely due to them sucking more current into them, then they were designer to draw.

The batteries only take what's delivered. They don't "suck"

[Eevo]

The batteries only take what's delivered. They don't "suck"

i agree but you can "hurt" a battery by delivering charge when its full.
a common example is AA battery chargers that work on a static timer.


i dont believe an alternator works like this though

[DiscoMick]

Hi Brett, what sort of lifespan were you getting from your batteries before fitting the redarc?

And - as a general question to anyone - what sort of life would you expect out of your batteries?

Obviously how the battery is used and what SOC it is drawn down to between charges also plays a big factor here.

Personally, I get around 5 to 8 years from a cranking battery, and the top shelf deep cycle i've got is now 3 years old. It's the first time i've bothered getting something decent as most of the time I have used old sealed lead acids that I get from work. Used to get 18 months to 2 years out of a half shagged one of those, but I used to dump them as soon as they showed signs of slowing down. I run a 38 litre Engel and a few lights off my system, and I've never seen voltages drop below 12.2 (no load) on my system, usually a lot higher, and most days when camping my solar panel can get them back to almost 100% most days unless it's crap weather - which is the only time the batteries drop below 12.4

Interested to hear everyones experience on this point.


Same here. Our 80 watt solar normally gets our camper battery charged by lunchtime at the latest. We had a lead acid deep cycle which eventually died and I've replaced it with a 110amp AGM, which seems to be a good thing so far.
The solar doesn't go through the DC-DC charger, which only becomes involved when the trailer is plugged into the vehicle and the engine is running.

[Homestar]

i agree but you can "hurt" a battery by delivering charge when its full.
a common example is AA battery chargers that work on a static timer.


i dont believe an alternator works like this though

Correct. A DC-DC unit can hurt the battery, whereas the alternator can't by it's very design.

[LRD414]

I have been following this thread with interest. It's actually turned out to have a lot of good explanations along the way for the inexperienced like me.

But I don't understand this one:confused:

A DC-DC unit can hurt the battery

I understood the earlier points regarding DC-DC devices being inefficient and in many cases not required. But this suggests there is more at stake? I have a Traxide DBS but I'd still like to understand this issue.

Cheers,
Scott

[Homestar]

I have been following this thread with interest. It's actually turned out to have a lot of good explanations along the way for the inexperienced like me.

But I don't understand this one:confused:


I understood the earlier points regarding DC-DC devices being inefficient and in many cases not required. But this suggests there is more at stake? I have a Traxide DBS but I'd still like to understand this issue.

Cheers,
Scott

DC-DC chargers are constant current units, not constant voltage like an alternator. If the unit faults, or is set incorrectly, it can continue to push current into the battery, damaging it or even destroying it or setting it on fire - all of those things have happened In the past.

An alternator can't 'push' any current into a battery, so as the battery charges, its current draw drops off, eventually to 0. No chance of damage to the battery.

[RoverLander]

Just for information...I wont be replying to rebutals..

On recent visit to the dealer i asked the following:

Is it normal for a D4 to cycle down to 12.2v while driving?
A) yes absolutely.. Its part of the energy management and fuel efficiency drive. Its normal.

Do you change any software or settings when a second battery system is installed?
A) No. We have no ability to do that.

Do you install second battery systems and how?
A) yes but we will only install DC/DC charger systems.. ( yes i know they only do that so they can steal more of your money...right?)

Ohhh Can you calibrate my dodgy fuel consumption readings... Out by 10%.
A) no we dont have access to that part of the software in the car. Only Landrover Aust or Factory may be able to do that....

Anyway thats the information I have....

[drivesafe]

On recent visit to the dealer i asked the following:

Is it normal for a D4 to cycle down to 12.2v while driving?
A) yes absolutely.. Its part of the energy management and fuel efficiency drive. Its normal.

Now does the dealer mean that this is the SET minimum operating voltage of a D4 or is because so many D4s have a fault in their operating system that it is BECOMING the norm to find D4s operating at 12.2v.

There is no way you can allow the alternator to drop to 12.2v at any time without causing the discharging of the battery.

Furthermore, to operate continually at 12.2v means that even a battery with full usable capacity available, the battery will never reach more than a 60% charge capacity, at best.

Plus continually charging a battery with only 12.2v, the battery will VERY QUICKLY loose the use of what capacity it has and will just simply go flat over night.

This is exactly what has been happening with the D4s that have had software problems. The alternator has been operating at 12.2v and the battery is not being charged and simply fails to hold a charge.

Even when periodically charged with a battery charger, the battery still goes flat in a very short time, and I am talking of time frames of a week or less.

A fully charged battery has a settled voltage of 12.7v, and if you fully charge a battery with a battery charger and then have an alternator operate at 12.2v, you will actually be flattening ( discharging ) the battery while you drive.

And no matter what the dealers "THINK", not even Land Rover can rewrite the laws of physics, ( even though they think they can ).

The MINIMUM CHARGE VOLTAGE for a 12v lead acid battery is 13.0v and even at this voltage level, if the battery is in a low state at the beginning of the drive, with an alternator voltage of just 13.0v, you would need to drive for at least 20 hours, WITH OUT STOPPING!

[RoverLander]

It seems that you have missed the point of variable voltage alternators and fuel savings drivesafe.

The car's software determines when the battery has reached full state of charge. Once that happens then it will use some of the energy in the battery to help minimise fuel consumption. It will use some of the battery's energy when the car needs moderate to full power..It does this by turning down the alternator output and therfore using less fuel. Some of the battery power is used to run the cars electrical system at that time. At those times the voltage will cycle down to 12.2v for a period of time.

The car wont let it stay at that voltage long enough to drain the main baterry significantly. When you then coast, brake or go down a hill the voltage jumps back up to 13.8 or upto 15v to recharge the partially discharged battery. It is this cycling that saves fuel.

Its is the complexity of this software managed algorithm that i dont want to interfere with and my reason for using a DC/DC charger. I dont know what assumptions that software makes about the capacity of directly connected batteries. The low voltage at times also impacts VSRs with them open and closing constantly as the voltage varies.

Peter

[jonesy63]

The car's software determines when the battery has reached full state of charge.

There's the rub - the software has a bug (maybe on just some cars) and is not just saving energy when the battery is fully charged.

Maybe Tata did the coding on the algorithm:wasntme:?

[drivesafe]

Hi Peter and I am well aware of how variable voltage alternators work, not just the LR version but for many types of other vehicles.

You obviously do not understand how and why variable voltage alternators systems are designed to work the way they do.

With any DC circuit, as you lower the voltage, "MOST" devices connected to the circuit, will lower their "CURRENT" demand.

So by lowering the voltage in a vehicle you lower the total current requirements of everything connected to the circuit.

If you lower the voltage output of the alternator to 12.2v, but you have a fully charged battery, you can not lower the circuit voltage below 12.7v without having to discharge the battery, and discharge the battery with VERY high currents.

To continually discharge a lead acid battery in conditions like what you are implying, will mean the battery is not only NEVER going to get to s fully charged state, it will progressively loose charge capacity and will eventually go flat over night.

This is exactly what has been happening with a large number of D4s, because they have a software problem, not because they are designed to DELIBERATELY operate at 12.2v.

Now for some more info for you.

DC/DC devices are one of only a few DC devices that do the opposite when the voltage is lowered. With a DC/DC device, to be able to maintain a constant output current, as the input voltage lowers, the DC/DC devices input current draw INCREASES.

So, if your misguided theory was correct and the D4 is deliberately designed to operate at 12.2v, then your DC/DC device would just accelerates the demise of your cranking battery.

Ford had the lowest operating voltage of 12.4v and had so much trouble that they raised the variable operating voltage but also allow the dealers to delete the operation altogether if a customer requests it removal.

Once again, the operating voltage of the D4 is not intended to be 12.2v, and those that are operating at that voltage are having problems with trying to charge their cranking battery.

Furthermore, as soon as the owners of these D4s, with the software problem, go to the dealers and get the software updated, their cranking batteries start charge properly on the drive home from the dealers.

[RoverLander]

Ok Tim, so it therefore shouldnt be too long before i have a flat cranking battery right? Any prediction on how long? I dont charge the battery with any other charger. If my cranking battery dies in the next 6 months then i am happy to concede that you have been right all along.

So far i have been going 3 months and 5000kms driving with cyclic 12.2v.

How long do I have before a battery failure?

[discotwinturbo]

If your saying your alternators were providing unregulated amperage? then they had a problem with the regulator, a properly working alt will not provide unregulated voltage or amperage.

My agm's should not be charged at more than 20-25amps. Batteries depending on S of C can pull more than they are designed to be charged at, therefore control is needed to prolong life...alternator will not prevent that from occurring (Disco may be different but not going to change from my method that works)

Brett....

[discotwinturbo]

Hi Brett, what sort of lifespan were you getting from your batteries before fitting the redarc? And - as a general question to anyone - what sort of life would you expect out of your batteries? Obviously how the battery is used and what SOC it is drawn down to between charges also plays a big factor here. Personally, I get around 5 to 8 years from a cranking battery, and the top shelf deep cycle i've got is now 3 years old.

2-3 years max for deep cycle batteries. I have never replaced a starter, as I have always given the starters a regular tickle with a battery charger.

Current 5 deep cycle batteries are minimum 5 years of age. Disco battery is 5 years old now, having been removed from previous car.

Camper batteries are almost 7 years and have been in 3 campers.

Brett...

[drivesafe]

Peter as already pointed out numerous times, the cranking batteries in the D4s with the software problems are going flat in a few weeks, max, not 6 months.

Hi Brett, all batteries have a maximum throughput of energy over their life span, and it makes no difference how you charge them, if you are a heavy user of battery power, the batteries will die sooner, of natural causes, than someone who only draws small amounts of energy when they use them.

So Brett, first off and the most obvious observation is that you are not using much energy from each of your batteries, probably because of the large number of batteries, which is good, but what is the likely hood that you would be getting the same or better life span from all those batteries if you just charged them off your alternator?

Furthermore, if we compare advantages between the way DC/DC devices work and how my systems work, then my systems will have your batteries lasting as long, if not longer, because my systems look after batteries far better than any DC/DC device would have a hope of doing.

My systems offer advantages like spreading the the current draw load over more batteries, which means a low current load per battery, compared to your set up, and this helps to extend the life span.

And each battery will not need to be discharged as low as yours will, for the same amount of energy used. This also helps to extend the life span.

Because none of the batteries in my system are as discharged as low as yours, they will have a larger number of cycles over their life span.

Because none of the batteries in my system are as discharged as low as yours, they will reach a fuller charged state at the end of a days drive, meaning more battery capacity for the next stopover, again, meaning the batteries in my setup are likely to have a longer life span.

If on the other hand, unlike your low usage, if someone is a heavy user of battery power while camped, then while it is highly unlikely that they will drive long enough to fully recharge their batteries, with any system, but with my system, because of the above advantages over DC/DC type setups, you will will have the ALL the batteries in a much higher state of charge at the end of a days drive.

So Brett, while your setup may work for you, it is nowhere near as effective at recharging batteries while driving, when compared to one of my systems and it has cost you a hell of a lot more to set and costs you more to charge your batteries while driving.

Last but not least, you have a 2 year limited warranty, while I back my gear with a 5 year unconditional warranty.

[Blknight.aus]

Just one point.

Not all Dcdc chargers are constant current a fair number of them attempt to replicate the output of an alternator and aim for a fixed volt?ge. With a varying amps rate once they are able to achieve that voltage.


For the purpose of this discussion the discrepancy is almost moot but for the fact that they won't overcharge a battery for the same reason an alternator won't and if your trying to diagnose them and are tracing the amps flow they behave slightly differently

[clubagreenie]

As an apples and oranges comparison. In the D2, hasn't been started in 6 weeks. Yellow top AGM, only ever alternator charged. Traxide USI-160 installed but only one battery ATM, voltage at battery 13.4v. Pretty sure starting will be no issue, I know it sits on 14.7 running and idling with all lights (incl 150w fyrlyts) fridge, UHF, stereo (200W x 4) etc still sits on 14.7v.

[Eevo]

is the charging software in the ecu or the alternator?

would be possible to change to a "normal" alternator?

[RoverLander]

Peter as already pointed out numerous times, the cranking batteries in the D4s with the software problems are going flat in a few weeks, max, not 6 months.

.

So Tim, given that my car cycles at down to 12.2v, do I have the software problem?

[drivesafe]

Hi Peter and how do you know it is cycling down to 12.2v.

Where are you taking the voltage measures?

[RoverLander]

Hi Peter and how do you know it is cycling down to 12.2v.

Where are you taking the voltage measures?

Two measures. OBDII reader and voltage display on my TPMS display wired to vehicle 12v supply. Both show cycling down to 12.2v on regular basis.

[SilvaD4]

So charging straight off the alternator really shortens the life of these batteries NOT.

What?:confused: All I did was post the charging specs for a D34 battery and somehow I am suggesting that an alternator will shorten the life of this battery.

[drivesafe]

What?:confused: All I did was post the charging specs for a D34 battery and somehow I am suggesting that an alternator will shorten the life of this battery.

No Silver, I posted that up to show that you had confirmed that an alternator does NOT harm Optima Yellowtops.

[drivesafe]

Two measures. OBDII reader and voltage display on my TPMS display wired to vehicle 12v supply. Both show cycling down to 12.2v on regular basis.

If your D4 is cycling down to 12.2v, then your cranking battery is being discharged while you drive and that is not the intended operation of any alternator, with exception of the Stop/Start setups, where they have their own separate battery.

[drivesafe]

is the charging software in the ecu or the alternator?

would be possible to change to a "normal" alternator?

Hi Eevo and sorry mate, I missed your post.

To my knowledge, there is no workaround for a Land Rover alternator operating system.

Nissans have a simple fix by cutting a single GREEN wire going to the back of their alternator and the alternator then runs at a constant 14+v all the time.

Toyotas can have an Alternator Voltage Booster Fuse fitted and the alternator then runs at 0.6v higher than it is programmed to.

As posted earlier in this thread, Ford allows the dealers to deactivate their Variable voltage system.

Most other vehicles don't need any adjustments as they run at high enough voltages that the batteries are charged properly anyway.

As to Land Rovers, there are few people around the world who develop special programs for Land Rovers, so with a bit of luck someone will come up with one to turn the variable voltage program off.

[Eevo]

what stops an owner ripping out that variable alternator and putting in an aftermarket constant voltage one?

[THE BOOGER]

The car would most likely go into limp mode as the ECU requires an alternator input and would read the change as a fault:(

[Eevo]

The car would most likely go into limp mode as the ECU requires an alternator input and would read the change as a fault:(

give the ecu a fake input that makes it happy.

[drivesafe]

give the ecu a fake input that makes it happy.

If only it was that easy.

The vehicle monitors the voltage of the alternator and adjusts the operating voltage according to whats happening elsewhere in the vehicle.

Remove the control off the alternator and the ECU ( BMS ) will have a hissy fit.

Maybe someone will find a simple fix like they now have for Land Rover's Stop/start operation.

A guy in the USA had a gut full of the way the Stop/Start worked in his new RRS and tried everything to get rid of it.

The Stop/Start has it's own small battery and he discovered that by removing the negative lead from the battery, the Stop/Start function was deactivated.

maybe there is something that simple to get around the Variable voltage operating in a D4.

[Eevo]

Remove the control off the alternator and the ECU ( BMS ) will have a hissy fit.



dont need to remove it, just make it do nothing, but make it think its doing what it wants.

bit hard for me to talk when i've not seen the system.

[incisor]

bit hard for me to talk when i've not seen the system.

never seems to stop you.... :angel:

[Eevo]

never seems to stop you.... :angel:

:bangin:

[Silenceisgolden]

Just one point.

Not all Dcdc chargers are constant current a fair number of them attempt to replicate the output of an alternator and aim for a fixed volt?ge. With a varying amps rate once they are able to achieve that voltage.


For the purpose of this discussion the discrepancy is almost moot but for the fact that they won't overcharge a battery for the same reason an alternator won't and if your trying to diagnose them and are tracing the amps flow they behave slightly differently

Proper multi-stage DC-DC converters charge at a constant current (bulk charge) until the drain from the subject battery drops to a certain level then they charge at a constant voltage (Absorb mode) for a fixed time, after which they drop to a lower constant voltage in float mode.
The constant current rating of the charger should be selected to match the maximum safe charging rate of the house battery, and the fixed voltage stages (absorb and float) are selected to suit the battery chemistry.
This charges the battery completely and safely. When charging from an alternator it is not possible to drop into float mode when the house battery is fully charged, so life of the house battery is reduced due to over charging. Similarly, the alternator has no way of knowing the safe maximum charge rate of the house battery so it can easily overcharge it in both modes.
That is why DC-DC chargers were invented........

[incisor]

When charging from an alternator it is not possible to drop into float mode when the house battery is fully charged, so life of the house battery is reduced due to over charging. Similarly, the alternator has no way of knowing the safe maximum charge rate of the house battery so it can easily overcharge it in both modes.
That is why DC-DC chargers were invented........ a reminder to all that may reply, that this discussion needs to remain "educational"

not "confrontational"

http://content.boards.baltimoreravens.com/public/style_emoticons/default/popcorn%20drama.gif

[Eevo]

a reminder to all that may reply, that this discussion needs to remain "educational"

not "confrontational"


factual and accurate too please

[Eevo]

house battery,

whats the difference between a house battery and car battery?

[drivesafe]

Hi Silenceisgolden and sorry mate but that is straight out of the advertising B/S they use to try to convince people that an alternator can't charge batteries but these wonder devices can.

First and foremost, the charging algorithms of DC/DC devices are a copy of how battery chargers operate.

As such, battery chargers can be connected and charging batteries for many months at a time.

This is why they have a float mode. If you kept a constant voltage of 14.4v on a battery, after about 24 hours, you would start to DRY the battery out.

So to avoid DRYING OUT the battery, these devices MUST lower the voltage being applied to the battery.

If you apply a constant voltage of 14.7 or higher, you will end up cooking a battery. Again, to avoid cooking batteries, chargers do not stay at such high voltages for very long. ( time depends on the chargers make and model )

Now as DC/DC devices use the same style of electronics as battery chargers, its just simpler to use the same algorithms.

It is as simple as that.

As for alternators shortening the operating life spans of batteries, there is not only no evidence to back that advertising crap, but reality and 60 to 70 years of RV use clearly demonstrates the exact opposite is the case. Just more misleading advertising hype, used to try to convince people they need something that will achieve nothing over what an alternator can do.

Now some real facts. How many times have you heard of an alternator cooking batteries, can't happen, but you hear of plenty of cases where DC/DC devices have cooked batteries.

How many vehicle manufacturers advise not to have a fridge powered from any battery being charged from the vehicles alternator?

There are a number of brands of DC/DC devices that state exactly that. You must not power a fridge from any battery being charged by their DC/DC device, because the fridge cycling on and off can cause many DC/DC devices to overcharge the battery.

Then there is the problem of mixing battery types. Not recommended when using a DC/DC device.

Yet when using an alternator, not only can you have any number of mixed battery types but they will each be charged at the optimum charge rate for each battery, regardless of type or state of charge. Can't do that with a DC/DC device ( or battery charger ).

With all the wonder devices on the market today, alternators are still the ultimate and safest way to charge any type of lead acid battery.

I could go on but most of you will get the CORRECT picture.

[Blknight.aus]

Proper multi-stage DC-DC converters charge at a constant current (bulk charge) until the drain from the subject battery drops to a certain level then they charge at a constant voltage (Absorb mode) for a fixed time, after which they drop to a lower constant voltage in float mode.
The constant current rating of the charger should be selected to match the maximum safe charging rate of the house battery, and the fixed voltage stages (absorb and float) are selected to suit the battery chemistry.
This charges the battery completely and safely. When charging from an alternator it is not possible to drop into float mode when the house battery is fully charged, so life of the house battery is reduced due to over charging. Similarly, the alternator has no way of knowing the safe maximum charge rate of the house battery so it can easily overcharge it in both modes.
That is why DC-DC chargers were invented........

spent about half a minute thinking about a verbose highly detailed detailed technical reply to that then decided, in the interest of not using up all the internet, reader interest and brevity to sum it up with 2 points which in order are
1.well done you opened up saying what I said, just with more and fancier words; and
2.Bet me.

after the edit------

also theres no need for me to o it when someone else has done it for me. And if you've got Eevo asking for factual and accurate information I can think of almost no better indication that your BS-o-meter should, if waved near your source data, peg and then bend the needle (sorry eevo, couldn't reist)

[Silenceisgolden]

Hi Silenceisgolden and sorry mate but that is straight out of the advertising B/S they use to try to convince people that an alternator can't charge batteries but these wonder devices can.
Dunno. I don't read advertising. I spent my working life designing electronic equipment and one project was designing and building in Australia a product that incorporated a very early adoption battery management system. For this I relied heavily on generous information from Sonnenschein batteries, back then the leaders in the field. This product was manufactured under the brand name of a Japanese based multi-national, a permission not lightly granted. I am not fully up to date with modern battery types such as Lithium, but am up to speed on AGM's.



First and foremost, the charging algorithms of DC/DC devices are a copy of how battery chargers operate.

As such, battery chargers can be connected and charging batteries for many months at a time.

This is why they have a float mode. If you kept a constant voltage of 14.4v on a battery, after about 24 hours, you would start to DRY the battery out.

So to avoid DRYING OUT the battery, these devices MUST lower the voltage being applied to the battery.

Exactly. The DC-DC charger can do this, the alternator does not. A 'smart' alternator will drop voltage to suit the cranking battery, not the house battery.

If you apply a constant voltage of 14.7 or higher, you will end up cooking a battery. Again, to avoid cooking batteries, chargers do not stay at such high voltages for very long. ( time depends on the chargers make and model )

Now as DC/DC devices use the same style of electronics as battery chargers, its just simpler to use the same algorithms.

It is as simple as that.

As for alternators shortening the operating life spans of batteries, there is not only no evidence to back that advertising crap, but reality and 60 to 70 years of RV use clearly demonstrates the exact opposite is the case. Just more misleading advertising hype, used to try to convince people they need something that will achieve nothing over what an alternator can do.

Now some real facts. How many times have you heard of an alternator cooking batteries, can't happen, but you hear of plenty of cases where DC/DC devices have cooked batteries.

How many vehicle manufacturers advise not to have a fridge powered from any battery being charged from the vehicles alternator?

There are a number of brands of DC/DC devices that state exactly that. You must not power a fridge from any battery being charged by their DC/DC device, because the fridge cycling on and off can cause many DC/DC devices to overcharge the battery.

Yes, this happens because as in my post, safe charging requires the voltage to drop to a float level when the battery draw drops to a specified level. If the fridge is running at the time when absorption should end, the current draw can trick the charger into thinking that the battery still requires more absorption charging. However, as soon as the fridge cycles off, the charger goes into float mode, so it is not a great problem with compressor type fridges. But note - your alternator will NEVER go into float mode to suit the house battery, so it WILL be overcharged and have its life reduced.

Then there is the problem of mixing battery types. Not recommended when using a DC/DC device.

Perfectly safe with a DC-DC device. Most allow you to select the profile of the house battery. Mixing should not be done with an alernator.

Yet when using an alternator, not only can you have any number of mixed battery types but they will each be charged at the optimum charge rate for each battery, regardless of type or state of charge. Can't do that with a DC/DC device ( or battery charger ).

Sorry mate, you have that the wrong way around. Maybe it is you who have been reading advertising B/S.

With all the wonder devices on the market today, alternators are still the ultimate and safest way to charge any type of lead acid battery.

I could go on but most of you will get the CORRECT picture.

[Tombie]

whats the difference between a house battery and car battery?


One starts your car..

The other one starts your house?!

[Homestar]

Sorry mate, you have that the wrong way around. Maybe it is you who have been reading advertising B/S.

Sorry, but it is you have it the wrong way around. No advertising BS, just that I understand physics. Alternators quite happily charge a mix of batteries and the batteries happily charge and live a long life. I have 3 different types in my system, and all stay fully charged and happy with just the alternator doing the work.

Notice that on DC DC devices and chargers the battery type is set from a menu or switch - so it knows what charge rate, voltage, etc to run at. My alternator doesn't ask what type of battery I have.

[RoverLander]

If your D4 is cycling down to 12.2v, then your cranking battery is being discharged while you drive and that is not the intended operation of any alternator, with exception of the Stop/Start setups, where they have their own separate battery.

No mentioning of B/S, Crap or claiming others are falsely advertising from me... I will stick to the subject.

I think many of our D4s are cycling down to 12.2v for periods of time. As most of us don't monitor voltage constantly we just wouldn't know.

I have spend a fair amount of time searching the net for a good explanation of variable voltage alternators and how they save fuel. There isn't much on the net but here are two articles. One states batteries getting down to 12.5V. It seems Land Rover may have taken that a step further.


Century Batteries:
http://www.centurybatteries.com.au/content/documents/battery-talk/issue-4-battery-talk-regulated-charge-control.pdf


AGCOAUTO
http://www.agcoauto.com/content/news/p2_articleid/350 (http://www.agcoauto.com/content/news/p2_articleid/350)


So we know that the car will use some cranking battery capacity to drive the cars electrical systems under certain conditions. When this happens voltage may drop to 12.2v for a period of time. The longest I have seen so far is about 10 minutes. The Body Control Module monitors battery state of charge and the state of the car (accelerating, cruising, coasting) to determine how it will use alternator power to charge the battery. The algorithm used and its exact parameters is not knows (except by some boffin at Land Rover). It may include the capacity and chemistry of the car battery.

While the car is operational the systems will monitor and track battery capacity. It will see any devices drawing current (including any DC/DC charging devices).

However when the car is asleep (switched off) it is probably that the BCM will not be monitoring what is being drawn from the battery. Therefore a second battery system connected directly to the car battery or that interferes with the SOC of the car battery while the car is asleep may cause confusion to the algorithms that manage the car battery.

A DC/DC charger can not cause this confusion. It is only active when the car is active and is fully visible to the body control module.

Yes, my car drives around at 12.2v from time to time. It did that before I fitted the DC/DC charge. It still does it now. I don't expect any cranking battery problems as a result.

See... no colourful language, blame, angst or provocation. I hope we see the same in any responses to my theory (with some evidence).

[drivesafe]

Originally Posted by drivesafe
First and foremost, the charging algorithms of DC/DC devices are a copy of how battery chargers operate.

As such, battery chargers can be connected and charging batteries for many months at a time.

This is why they have a float mode. If you kept a constant voltage of 14.4v on a battery, after about 24 hours, you would start to DRY the battery out.

So to avoid DRYING OUT the battery, these devices MUST lower the voltage being applied to the battery.

Exactly. The DC-DC charger can do this, the alternator does not. A 'smart' alternator will drop voltage to suit the cranking battery, not the house battery.

First off, how many vehicles have smart alternators, or the correct terminology is VARIABLE VOLTAGE ALTERNATORS.

Even today, most vehicles have alternator voltage levels that never go below 14.2v, so why do all these vehicle not have the problems you fictisiously claim they will. Once again, reality proves you wrong.

But lets forget REAL facts for now. Above, in this post, you stated A 'smart' alternator will drop voltage to suit the cranking battery, not the house battery.

Then you state. But note - your alternator will NEVER go into float mode to suit the house battery, so it WILL be overcharged and have its life reduced.

So according to you, an alternator both drops its voltage but still manages to over charge the house battery. Now thats one clever feat.

Mixing ( battery types ) should not be done with an alernator

It is a well established FACT that an alternator can SAFELY and properly charge banks of mixed battery types and does it far better than any other charging system. And this is fact, not your fiction.

[Tombie]

Enormous amount of CSB in this thread....

People challenging facts whilst presenting none of their own... And always pushing the DC-DC hype.

Those with DC-DC chargers; that's fine... But here is the only valid argument for your set-up.

"I spent a lot of money on an electrical DBS charging system that works for me."

Any other attempt to justify such expenditure/complexity is defying simple physics and electrical knowledge.

There is not a Land Rover out there at this point in time that requires such a system to effectively charge or maintain their Multi-battery installation.
(Assumption: Wiring and connections/storage cells are up to scratch)

[drivesafe]

Peter, I have no idea what your reason was for posting that document. It pretty well confirms what I have been posting.

If you discharge a battery down to 60% SoC or 12.2v as you claim is happening, then it will take quite a few hours of continuos driving with an alternator voltage of 14.4v, to recharge that battery.

This is something I have already pointed out and that info is in the document you just posted up.

But you yourself stated you could not find any reference to batteries being discharged any lower than 12.5v or 90% SoC.

And just for your info, the EU has had these Emission Control Regulations in place since 2005 and hence the reason why the D3 was one the first vehicles in Australia with Variable Voltage Alternators.

So if your D4 is running at 12.2v, ( and I suspect its just the voltage readings not the actual battery voltage level ), but if your battery is running that low, its not going to last very long.




While the car is operational the systems will monitor and track battery capacity. It will see any devices drawing current (including any DC/DC charging devices).

Actually, the D4 can not see any other current draw other than the cranking battery itself., That is the only current draw the D4 is set up to monitor.


However when the car is asleep (switched off) it is probably that the BCM will not be monitoring what is being drawn from the battery. Therefore a second battery system connected directly to the car battery or that interferes with the SOC of the car battery while the car is asleep may cause confusion to the algorithms that manage the car battery.

There is a little problem with this theory in that most D4s that have had a problem with low operating voltages are in the Uk and almost none of them had any form of dual battery system fitted. The problem was as stated, is a software problem, and once the software is updated, as has been the case here as well, the problem ceased to exist.

[Blknight.aus]

No mentioning of B/S, Crap or claiming others are falsely advertising from me... I will stick to the subject.

I think many of our D4s are cycling down to 12.2v for periods of time. As most of us don't monitor voltage constantly we just wouldn't know.

I have spend a fair amount of time searching the net for a good explanation of variable voltage alternators and how they save fuel. There isn't much on the net but here are two articles. One states batteries getting down to 12.5V. It seems Land Rover may have taken that a step further.


Century Batteries:
http://www.centurybatteries.com.au/content/documents/battery-talk/issue-4-battery-talk-regulated-charge-control.pdf (http://www.centurybatteries.com.au/content/documents/battery-talk/issue-4-battery-talk-regulated-charge-control.pdf)


AGCOAUTO
http://www.agcoauto.com/content/news/p2_articleid/350 (http://www.agcoauto.com/content/news/p2_articleid/350)


So we know that the car will use some cranking battery capacity to drive the cars electrical systems under certain conditions. When this happens voltage may drop to 12.2v for a period of time. The longest I have seen so far is about 10 minutes. The Body Control Module monitors battery state of charge and the state of the car (accelerating, cruising, coasting) to determine how it will use alternator power to charge the battery. The algorithm used and its exact parameters is not knows (except by some boffin at Land Rover). It may include the capacity and chemistry of the car battery.

While the car is operational the systems will monitor and track battery capacity. It will see any devices drawing current (including any DC/DC charging devices).

However when the car is asleep (switched off) it is probably that the BCM will not be monitoring what is being drawn from the battery. Therefore a second battery system connected directly to the car battery or that interferes with the SOC of the car battery while the car is asleep may cause confusion to the algorithms that manage the car battery.

A DC/DC charger can not cause this confusion. It is only active when the car is active and is fully visible to the body control module.

Yes, my car drives around at 12.2v from time to time. It did that before I fitted the DC/DC charge. It still does it now. I don't expect any cranking battery problems as a result.

See... no colourful language, blame, angst or provocation. I hope we see the same in any responses to my theory (with some evidence).

gunna be fair here we asked for evidence, fact and proof, you gave us an advertising blurb from a battery company on that I'd probably, without further research, consider betting is involved wit ha susiduary company that manufcatures DC/DC chargers and other gubbinary that is efectively just a poor substitute for some proper reseach and application of knowledge. of course why bother going to that effort when for just the low price of, you dont have to and hell for just $15 more we'll even arrange installation.

claiming the BECM will always know whats being drawn out simply isnt true if you've patched a DC/DC charger (or any other load) into the system where the amps its drawing cant be monitered then the becm wont know how much charge is making it to the battery. IF its got the alternator out put set to 15 amps because it knows the state of charge is 80% and that the car only needs 14 amps to meet the switched on loads if you've got a DC/DC in there thats pulling an unseen 10 amps to put 3 amps into your second battery and run your fridge then your cranking battery is slowly discharging.

its entirely possible to develop the situation where with the battery being pulled down by the DC/DC charger and then robbing the expected amps that are supposed to be going back into the battery leaving it in a lower than expected SOC.

so lets say you wind up a number of short drives on a nice warm afternoon, with a cosey battery, the BECM has shut down with what it thinks is a 60% battery thats enough or a start. you park up the vehicle it rains and theres a cold snap overnight. its first thing in the morning now and you goto crank it over, the starter engages and the battery voltae dips to 10.2v. What happens?

now at this point its your call.

I can quite easily diatribe on about the facts about dc/dc chargers and tell you that I'm trying to teach you thats option one but I dont reckon its going to work.

OR

I can rip open a thread and do q/a on everything you've thrown uprange we'll call it a ranging shot and I'll give you some little corrections and let you shoot again and we'll just keep doing that and eventually you'll bracket yourself in and drop some around the target then with simple logic and evidence you'll drop the next salvo on target. I'll call it learning, you'll call it everything but right up untill you hit the straddle and then put the rounds on target. then you'll call it knowledge.

Or.

we can simply run with everyone can have their own opinion. Just beware that unlike people opinions are not all created equal some are a great deal more researched and robust than most.

so far your "research" is an adverstising blurb and your pushing up against some substantially qualified and experienced persons here.

as a final freebie bit of advice. look up right, numbers while manipulable dont generally lie by themselves.

[Redback]

I can never understand why people think a DC-DC Charger does a better job than an alternater, this means that all the car manufacturers in the world are wrong and the manufacturers of DC-DC Charger are right and know better.

I have a friend that has a setup that doesn't use any form of DBS or DC-DC Charger, he uses the alternater to charge both his batteries, he uses a battery clamp switch to isolate his batteries when stopped, it's a manual version of a DBS basically, as well, when he had his camper, it was the same, the wire ran back to the camper and the alternater charged that battery as well, now I've known Howard for a long time and I can tell you, he's no dill, tight maybe(Scottish heritage) he's been doing this long before I've known him, so if it has been working well for all these years via the alternater, why use a DC-DC Charger, trust me, if there was a better way that saved Howard money, he would do it.

Baz.

[Silenceisgolden]

I can never understand why people think a DC-DC Charger does a better job than an alternater, this means that all the car manufacturers in the world are wrong and the manufacturers of DC-DC Charger are right and know better.

Baz.

Nor can Drivesafe or Blknight understand it, but it is not that complicated really. The requirements of the house battery and the cranking battery are quite different, and hence different types of batteries are used and require different charging regimes.

[THE BOOGER]

I don't understand it either, I want my aux battery and cranking bat to charge as fast as possible and a DC DC just does not do this unless I spend a grand or so just for the charger. I think some times the supposed different charging of house verses cranking is exaggerated just for sales. I hope I am not a luddite I don't have one of Tims units I have 1 from his competitor (ABR) and have up to 4 aux batteries in the disco all AGM but a standard Cranking bat some of my AGM batteries are 6 years old and still going. Much is made of alternators not charging or being to slow to charge the last 3% I don't think the cost is worth the outcome and if my alt cant get things fully charged then a DC/DC probably will not have time to fully charge them either':)

[Tombie]

Nor can Drivesafe or Blknight understand it, but it is not that complicated really. The requirements of the house battery and the cranking battery are quite different, and hence different types of batteries are used and require different charging regimes.

If it is so 'simple' then why is it yourself and others do not seem to be able to articulate it?

House battery and Main battery are different "how"? ;)
Because its all the "way back there"?

Again, all data, physics, electrical theory (and practice) show that a house battery can and will be charged if sufficient cabling, clean connections and installation are up to scratch.


By your (and others) arguments - no DBS not utilising a Dc-Dc device can function - yet tens of thousands of vehicles have proven this to be incorrect...

Several users on this forum are running DBS using multiple brands of isolators (Traxide, Redarc etc) and successfully maintained and charged multiple batteries both in vehicle and in trailers/caravan.

We went 10 days on 2 house batteries (2x90ah AGM), linked to 2 aux D34 Optimas in the vehicle, as well as the main factory battery.

When we left the Van had run down to 12.3v (left disconnected for too long pre-trip) and by the time we had done a few hours travel on day 1 was at 12.6v...

Day 2 saw the house batteries and aux at 99% SOC on the gauge....

Considering the system in the van is always drawing (fridge etc) and has no solar currently - this system is working just fine..


A week long trip to Maralinga, without van, saw the Optima set up run camp lighting, audio, fridge (as freezer, mmm Ice creams) without interruption.


For better or worse, my vehicle has never seen a battery charger for a top up, does a combination of short and long drives (M-F the total distance per day is 4.6km) and has a rested voltage at the main of 12.73v as of 15 minutes ago...

The aux system is sitting at 12.74v

Not a Dc-Dc device in sight :cool:

[bee utey]

Yeah but, specification envy, the driver of all new gadget purchases...triple the cost of the widget for a few % gain in perceived performance and you'll sell them in their thousands... remind me why people buy D4s when there's a perfectly good horse/Model T/series/D1/D2 in their garage...;)

:):):)

[SimmAus]

9 pages in and no one has mentioned installing a Flux Capacitor...worked well in the DeLorean ;-)

Disclaimer: This might not be educational nor factual.

[incisor]

9 pages in and no one has mentioned installing a Flux Capacitor...worked well in the DeLorean ;-)

Disclaimer: This might not be educational nor factual.

but it is amusing :p

[Silenceisgolden]

By your (and others) arguments - no DBS not utilising a Dc-Dc device can function - yet tens of thousands of vehicles have proven this to be incorrect...
:cool:

Look, no-one is saying that the older technology doesn't work. I have an old technology Defender and it works very well. I also have a new technology D4 and it works better.

That's all there is to it - modern technology usually does have benefits, but that doesn't mean that the old things were complete duds.

But is is silly for users of old technology to state that new technology is all just advertising B/S.

[Tombie]

Look, no-one is saying that the older technology doesn't work. I have an old technology Defender and it works very well. I also have a new technology D4 and it works better.

That's all there is to it - modern technology usually does have benefits, but that doesn't mean that the old things were complete duds.

But is is silly for users of old technology to state that new technology is all just advertising B/S.

A D4 doesnt work any better than a Defender... Especially MY for MY...

And the claim that Dc-Dc is new technology and therefore better is misleading.

Dc-Dc tech has been available for a long time, its just commercially cheap now.

By your logic (implied in the post) - Active ECU controlled Alternators (latest tech) should be superior to old tech (Dc-Dc converters).

There is a claim that the "new tech" Dc-Dc charger works better...
Yet this contradicts the exact benefits of other systems... These Dc-Dc systems introduce:


Restricted current capacity
Increased charge time
Restricted to specific battery type mix (must be selected on unit)

It provides a sub-optimum result for the end user... Both physically and financially... When the capital outlay of improved cabling (biggest issue in poor 12v charging) and connection would see the user happily for reduced cost and complexity.


The biggest benefit to Dc-Dc systems is installers can use sub-optimal wiring and get away with it (most of the time).


Explain to mehow a Bickie Dipper; many of which do only 3-4 hours driving a day, pumping 25ah via a Dc-Dc converter into a battery bank of 2-4 batteries (assume 300-400ah) and free camping using 50% of their capacity - therefore 200ah consumed (tv, laptop, radio, lights, microwave etc) is going to charge their batteries to even remotely 80% SOC in that time?


The only way they will remotely get there is Solar, and a decent amount of it...


Their alternator, unconstrained by a Dc-Dc device would have been throwing much more current out there in that 4 hours....

[BigJon]

But is is silly for users of old technology to state that new technology is all just advertising B/S.

It would only be silly if the new technology had tangible (or indeed any) benefits over the "old" technology.

[SBD4]

A perspective from an installer of Thumpers (portable DBS) - clear and to the point. They are another industry player that makes their bread and butter from doing this day in and day out. If Tim's and Dave's extensive experience are not enough to convince then perhaps another similar player will lend weight to convince:

http://www.home12volt.com.au/uploads/2/6/0/5/2605767/dc_chargers_and_the_alternatives_-_vehicle_charging.pdf

In short they do not advocate DC-DC systems. They do advocate properly understanding and assessing when you might need one though.

With respect to D4 alternator voltages sticking at 12.2V, Get the software update and fix the issue so the alternator can do the job it was designed to do. Regardless of whether or not the battery is lasting at this voltage, the point is it will last longer if this is fixed. With the patch installed, there will be no need to have this discussion.

[SBD4]

... These Dc-Dc systems introduce:


Restricted current capacity
Increased charge time
Restricted to specific battery type mix (must be selected on unit)
....[/COLOR]

...and one more...

Losses through inefficiency

[THE BOOGER]

9 pages in and no one has mentioned installing a Flux Capacitor...worked well in the DeLorean ;-)

Disclaimer: This might not be educational nor factual.
Tried 1 a few years ago but flux capacitor kept interferring with the poleriser and the hyclone

[Silenceisgolden]

A perspective from an installer of Thumpers (portable DBS) - clear and to the point. They are another industry player that makes their bread and butter from doing this day in and day out. If Tim's and Dave's extensive experience are not enough to convince then perhaps another similar player will lend weight to convince:.

As you say, a similar player - that is, a player with a vested interest in selling a solenoid system over a DC-DC system.

That's all from me - I am batting my head against a brick wall offering unbiased information to those whose minds are made up.

[Eevo]

That's all from me - I am batting my head against a brick wall offering unbiased information to those whose minds are made up.

its hard to take you seriously when you sounds like a sales brochure.

[Tombie]

As you say, a similar player - that is, a player with a vested interest in selling a solenoid system over a DC-DC system.

That's all from me - I am batting my head against a brick wall offering unbiased information to those whose minds are made up.


But you're NOT unbiased.... Review your posts..

12v shop as the example will happily sell you whatever you NEED..

They have a level of ethics in their customer service that is very good... (As does a Tim, who whilst happy if you buy from him freely gives legitimate and accurate advice to users of competitors products)

They (12V shop) could offer you the Thumper, then suggest a DC-DC charger is required; but they don't... Because it's just not needed.

So who should be banging their head on a wall now?! :D

[harro]

I use a simple redarc VSR for my dual batt system in the vehicle and my 200 A/h storage in my camper and have never had an issue.
That said I have read many of Collyn River's articles on 12 volt sytems and charging etc. and found them most helpful.

I would think there would be applications for a DC to DC charging system and then there would be situations where it would be a waste of time and money.

Like any modification to the original it requires research and good information and at the end of the day as long as you are happy with the results then that is all that really matters.:)

Cheers,
Paul.




Tech: DC-DC battery management | Caravan World Australia (http://www.caravanworld.com.au/features/1202/tech-dc-dc-battery-management/)

[Tombie]

Whilst those publications have improved in recent revisions - it doesn't take much to write your own book and have it published.

Much of the early information was borderline...

[Tombie]

For clarification - I worked on Military Rotary Wing Aircraft electrical and electronics with Avionics, and Weapons systems.

Everything in there was done to a very high standard - as one would expect...

When working with low voltage applications correct material choices, connections etc are paramount to efficient operation.

[Redback]

Nor can Drivesafe or Blknight understand it, but it is not that complicated really. The requirements of the house battery and the cranking battery are quite different, and hence different types of batteries are used and require different charging regimes.

I was under the assumption that all lead acid batteries were the same and that an alternater will charge them all without a problem :(

Baz.

[Tombie]

I use a simple redarc VSR for my dual batt system in the vehicle and my 200 A/h storage in my camper and have never had an issue.
That said I have read many of Collyn River's articles on 12 volt sytems and charging etc. and found them most helpful.

I would think there would be applications for a DC to DC charging system and then there would be situations where it would be a waste of time and money.

Like any modification to the original it requires research and good information and at the end of the day as long as you are happy with the results then that is all that really matters.:)

Cheers,
Paul.




Tech: DC-DC battery management | Caravan World Australia (http://www.caravanworld.com.au/features/1202/tech-dc-dc-battery-management/)


This paragraph alone should have people questioning the validity of his data..


Today, even low-priced cars have more computing power than had early space craft. Their vehicle electronics are rugged enough, but typically require 13.8 volts to run, and some only 13.5 volts ? far too low for charging. And they require that voltage to be stable. Further, adding an auxiliary battery bank may not necessarily cause problems, but is all but certain to be blamed if things go wrong. It may also invalidate the warranty.

[drivesafe]

Hi again Silence, you and your mate Peter, haven't the foggiest idea how DC/DC devices actually work, but before giving you an education on how BAD they are in your situation, maybe some history on alternators is called for.

Up until about 10 to 15 years ago, the standard alternator size varied from 45 to about 80 amps, the most common being 55 amp.

The output current of an alternator depends on the RPM the alternator is being spun at, which is based on the motor's RPM, and while cruising down the highway, the motor's RPMs will be high enough to turn the alternator at a speed that allows the alternator to produce it's maximum output current at it's MAXIMUM VOLTAGE.

But get into bumper to bumper traffic and the motors RPMs drop to such a low rev that the alternator can only produce a small percentage of it's total capacity.

So in slow or stopped traffic conditions during the day time, the alternator was flat out producing enough current to meet the basic demands of the vehicle.

At night and during winter, with headlights on, heaters and air conditioners going and probably the sound system cranked up, and the alternator has no hope of producing enough current to power everything.

At this point you would think you would overload the alternator.

But not so, because alternators have a natural way of compensating for current loads that are greater than their maximum output capability, the alternators current level, even when reduced by low RPMs, remains the same but the alternators output VOLTAGE drops.

As I have already pointed out earlier in this thread, it is also the natural operation of most DC appliances to lower their current demand as the voltage drops.

So eventually you get to a lower voltage but the current demand on the alternator levels out.

The problem is that if the voltage has to drop too low to get the current demand down to the alternators maximum capacity at low revs, you now have a situation where the voltage drops below the voltage level of the cranking battery and now the vehicles current demands own are being met by both the alternator and the cranking battery.

So RoverLander, that document you posted up is nothing new and this has been happening for at least the last 60 or 70 years, since alternators have been used in the automotive industry.

Now to present day and D4 operations.

Alternator sizing is still based on what a vehicle needs, when in traffic or idle situations.

The only difference is that vehicle power consumption is now hugh and so we now have alternators with hugh output capacities. A D3 with 140 amps and D4 with 180 amps.

But even these high current alternator can still only provide enough energy at idle or in traffic to maintain the vehicles own energy requirements.

So you still have situation where the vehicles energy requirements will exceed the maximum available current output of the alternator and just as has been the case for the last 60 to 70 years, if the current demands are too high and the alternators voltage level is pulled down to the cranking battery's voltage level, the cranking battery will have to make up the short fall.

Now throw a DC/DC device into the system and you have real current load problems.

As also posted in this thread, DC/DC devices are one of the few DC devices that actually increase their current draw as input voltage drops.

So at the very time when you need to reduce the current load in your vehicle, here is a DC/DC device drawing more and more current as it forces the vehicles voltage even lower.

With the alternator already at full output capacity, this hugh increase in current demand has to come from the only source available to provided it, your cranking battery.

In your case RoverLander, you may be correct, your operating voltage of 12.2v may very well be that of the cranking battery, all because your DC/DC device is giving your cranking battery a hammering. Thats a good setup mate.

With one of my systems fitted and if you end up in a traffic situation, the voltage will still drop, but all the batteries in the system will draw less and less current as the voltage drops.

If the load is still greater than what the alternator is producing, say you might by out off roading at night with heaps of lights on.

With my system, while you will still have to draw power from the batteries, the additional current load is now spread out over all the batteries, which means your cranking battery is never going to be worked as hard as it would be in a D4 without a dual battery system and would be miles less current drawn off the cranking battery is it has to be in your.

An additional benefit with my setup over a DC/DC setup, where the cranking battery would get a caning in such situations, whereas with my system, the cranking battery will have had the least amount of energy drawn from it, so when you do get back to decent speeds, the cranking battery in one of my setups will be fully charged in a fraction of the time needed to charge the cranking battery in your setup.

So why on earth would any clear thinking person want to put a DC/DC setup in a D4?????

[Silenceisgolden]

I was under the assumption that all lead acid batteries were the same and that an alternater will charge them all without a problem :(

Baz.

No baz, not really. Some lead-acid batteries are designed specifically for 'house' duties and are termed deep cycle batteries. That means they can be deeply discharged without huge damage. They are not necessarily designed so much for very high current discharge but for heavy total discharge. That is, low drain for long periods.

Other lead-acid batteries are designed for cranking the engine which requires a very high current but only for short duration. These batteries can be damaged by even infrequent discharging.

There are of course also many different types of deep cycle and cranking batteries, all with their own ideal charging regimes.

[Homestar]

No baz, not really. Some lead-acid batteries are designed specifically for 'house' duties and are termed deep cycle batteries. That means they can be deeply discharged without huge damage. They are not necessarily designed so much for very high current discharge but for heavy total discharge. That is, low drain for long periods.

Other lead-acid batteries are designed for cranking the engine which requires a very high current but only for short duration. These batteries can be damaged by even infrequent discharging.

There are of course also many different types of deep cycle and cranking batteries, all with their own ideal charging regimes.

Yep, and they'll all charge up no dramas just connected to an alternator, regardless of what mix you run.

[Eevo]

so if alternators are so bad, why have car manufactures been using them for the last 60+ years instead of dc-dc chargers?

[manic]

A couple of questions:

Do DC-DC chargers get a a battery up to a higher state of charge. Most alternators get a battery up to ~85%?

The five step charge process on a C-tek (for example), is it a gimmick or is there value in desulphation, float and pulse modes?

Its clear that an alternator charges faster, and that most do not need a DC/DC. But if charge time was not an issue, and the battery is mostly above 75% is a DC-DC charge going to keep a battery in better health?

[Tombie]

Most alternators get a battery up to ~85%?





Myth.....

[Tombie]

Most batteries run lower state of charge because of "urban cycling" - that is never run long enough to charge fully...

[Silenceisgolden]

A couple of questions:

Do DC-DC chargers get a a battery up to a higher state of charge. Most alternators get a battery up to ~85%?

The five step charge process on a C-tek (for example), is it a gimmick or is there value in desulphation, float and pulse modes?

Its clear that an alternator charges faster, and that most do not need a DC/DC. But if charge time was not an issue, and the battery is mostly above 75% is a DC-DC charge going to keep a battery in better health?

Yes, DC-DC charger gets batteries close to fully charged, but it is only a small amount of benefit. The de-sulphation (pulse) mode is more for rejuvenating cranking style batteries that have been deeply discharged and is not totally relevant to deep cycle batteries.
The big benefit of DC-DC chargers is prolonging the life of the house batteries, because when the battery is fully charged the charger drops down to float mode instead of continuing to charge like an alternator will do. Over charging is not as damaging as over-discharging, but it will shorten battery life.
The alternator does not necessarily charge faster. Provided the DC-DC charger is chosen to suit the battery capacity it should be faster than the direct alternator connection and there is not the risk of the alternator charging at too rapid a rate for the battery.

[Tombie]

Manic - the process of charging a battery is simple.

Apply Voltage above battery voltage (think of this as force or pressure).
Now apply amperage available for the battery to absorb this energy.

A battery charger, DC-DC device, or alternator produces this output... And if the battery is in a state to absorb it it will.

A battery in a lower SOC will draw more current initially and this reduces as the battery gets to higher SOC.

To answer your question; a good battery charger will have some functions to prevent sulphation however this is more suited to batteries in storage.

As for DC-DC charger Vs Alternator and time...
Either will charge a battery to full charge given the time...

[Homestar]

Yes, DC-DC charger gets batteries close to fully charged, but it is only a small amount of benefit. The de-sulphation (pulse) mode is more for rejuvenating cranking style batteries that have been deeply discharged and is not totally relevant to deep cycle batteries.
The big benefit of DC-DC chargers is prolonging the life of the house batteries, because when the battery is fully charged the charger drops down to float mode instead of continuing to charge like an alternator will do. Over charging is not as damaging as over-discharging, but it will shorten battery life.
The alternator does not necessarily charge faster. Provided the DC-DC charger is chosen to suit the battery capacity it should be faster than the direct alternator connection and there is not the risk of the alternator charging at too rapid a rate for the battery.

Not sure how many times it's been mentioned, but an alternator WILL NOT overcharge a battery, it simply can't. PLEASE stop pedalling this myth. If alternators overcharged batteries, we would all have dead cars all the time. I don't care if it's a lead acid, AGM or pink with purple dots, as the batteries charge increases, the current draw drops off. The alternator will only provide what the battery needs, it CANNOT provide current to a battery beyond this.

Do the physics, chemistry and math - those laws are well proven.

Why do you not believe the people on here saying this? The 4 main protagonists against your argument are some of the most respected and highly qualified people in their fields. All have vast electrical, electronic and automotive experience and together would have over 100 years of experience in this sort of stuff. Thier not technophobes, they just intimately understand the subject.

Sorry, but you're continual denial of their explanations is just making you look silly. I'd cut my losses and run, even if you won't accept their advice.

[manic]

Sure I get it. I have a voltage meter on the dash and I can see the alternator is often knocked down to ~13v so I figured a DC-DC at nearer 15v might be quicker at topping up batteries and the alternator quicker at restoring bulk.

I'm considering the following set up.

Starter Battery
Deep Cycle Battery (AUX)

All Auxilary sockets, fridge, lights etc run off a 100AMP relay that gets power from the starter/alternator when the car is running and switches to the Aux battery when starter voltage drops below ~12.4v

A DC-DC charger is the only device connected to the AUX bat when the engine is running.

This set up will see all devices powered by the alternator when engine running, and the starter battery will get charged quickly (priority) from the alternators bulk amperage. The AUX will get a regulated DC-DC charge without having to provide any power.

On short stops the starter battery is likely to provide the required power, on longer stops the AUX takes over with solar support.

On a 90 with a small fridge and LED lighting I think this set up might see the AUX battery kept at a high/better state of charge most of the time. Especially when the vehicle is not being used for camping.

[Silenceisgolden]

it CANNOT provide current to a battery beyond this.
Geez....

Obtain a 14.5 volt regulated supply, connect it to a battery and leave it there.... call me back when the battery stops drawing current.

[Silenceisgolden]

Sure I get it. I have a voltage meter on the dash and I can see the alternator is often knocked down to ~13v so I figured a DC-DC at nearer 15v might be quicker at topping up batteries and the alternator quicker at restoring bulk.

I'm considering the following set up.

Starter Battery
Deep Cycle Battery (AUX)

All Auxilary sockets, fridge, lights etc run off a 100AMP relay that gets power from the starter/alternator when the car is running and switches to the Aux battery when starter voltage drops below ~12.4v

A DC-DC charger is the only device connected to the AUX bat when the engine is running.

This set up will see all devices powered by the alternator when engine running, and the starter battery will get charged quickly (priority) from the alternators bulk amperage. The AUX will get a regulated DC-DC charge without having to provide any power.

On short stops the starter battery is likely to provide the required power, on longer stops the AUX takes over with solar support.

On a 90 with a small fridge and LED lighting I think this set up might see the AUX battery kept at a high/better state of charge most of the time. Especially when the vehicle is not being used for camping.

Yep, an excellent set-up. I do my motorhome that way, but I would suggest that you switch your loads to the house battery at 12.7 volts. You really always should have your cranking battrey at peak charge in case of freezing cold morning starts!

[Homestar]

Obtain a 14.5 volt regulated supply, connect it to a battery and leave it there.... call me back when the battery stops drawing current.

There, you just said it - when the battery stops drawing current. Not the alternator forcing more in than the battery is drawing. You're whole argument is moot as if your theory was correct, please explain how the cranking battery lives happily for years being charged at these voltages?

It's a point that's been mentioned a dozen times here but you conveniently ignore.

[drivesafe]

This paragraph alone should have people questioning the validity of his data..

Quote:
Today, even low-priced cars have more computing power than had early space craft. Their vehicle electronics are rugged enough, but typically require 13.8 volts to run, and some only 13.5 volts ? far too low for charging. And they require that voltage to be stable. Further, adding an auxiliary battery bank may not necessarily cause problems, but is all but certain to be blamed if things go wrong. It may also invalidate the warranty.


Hi Tombie and I wouldn't give that "journalist" any credence what so ever, and that quote of his you posted up is really ironic.

I have had plenty arguments with him over the years and he is by far one of the most disingenuous individuals I have ever come across.

About 5 years ago, I was on a caravan forum explaining to a Toyota owner how the variable voltage worked on Toyotas and how it differed from how Land Rovers system worked.

Then, totally uninvited he posts up that there is no such thing as alternator working voltages below 14v, they never have and it was all B/S.

Now thats from a bloke who is a self-proclaimed expert in this field.

[drivesafe]

Other lead-acid batteries are designed for cranking the engine which requires a very high current but only for short duration. These batteries can be damaged by even infrequent discharging.

What a load of crap, while dedicated deep cycle batteries should not be used as starting batteries except in an emergency, there is absolutely no reason why you can not use a cranking battery as a deep cycle battery.

Before any form of deep cycle battery was available for RV use, everybody used cranking batteries as there auxiliary/house batteries and they had no problems.

The primary difference between a dedicated deep cycle battery and a cranking battery when used in cycling applications, is that you get more cycles from a dedicated deep cycle battery than you do from a cranking battery.

But this is why deep cycle batteries are dearer than cranking batteries. But the amount of energy you get from each type of battery is about dollar for dollar the same.

Try getting the correct info before lecture others on a subject you quite obviously don't understand.

[RoverLander]

Ohhh I love this topic.... we should do it every few yearsjust for fun JStill no colourful language or abuse of people from me... sticking on topic J

First to Tim's point about a low revving alternatorproducing less power. I think you have a point on a DC/DC charger increasingits current draw at a time of low alternator output. I had not considered that(see I can admit when someone makes me think of something else). However I don'tthink I have seen that scenario in my D4. When just after starting to drive andthen idling (while the main battery is still being recharged) I still see ahigh voltage (well above 13.4v) so I don't think the D4 alternator suffers fromreduced voltage due to an idle situation. Its capacity and design is such thatI don't see this problem. I will look out for that though now that you havementioned it.



Tim you mentioned:
?If you discharge a battery down to 60% SoC or 12.2v as you claimis happening, then it will take quite a few hours of continuos driving with analternator voltage of 14.4v, to recharge that battery?.



I know you know that an open circuit voltageand a battery voltage under load are very different. Yes I get a 12.2v voltageunder load (from the car drawing power). This does not indicate a 60% state ofcharge. The car is achieving fuel savings (and fuel savings I am very happywith!) by at times restricting alternator 'drag? on the engine. At these timesthe battery supplements the cars electronics. Short of stopping the car,disconnecting the battery and waiting a few hours before taking the crankingbattery voltage.... i don't know to what SOC... However I trust that the LandRover engineers have figured that out and that it is perfectly fine.

Re Different battery types and charging:Different chemistry types require different charge rates and voltage rates tomatch their chemistry. The top voltage ranges from 14.2 up to 15.1. All theevidence/opinions on this forum suggests that no matter what types of batteriesand capacities, just hook them up to an alternator and at the end of any lengthof cable as long as its thick enough and you should be OK. You may never get afull battery but you should get by. My preference is to hook each (car andcaravan) to a device that is set to the specific charging requirements of thebattery and its SOC and let it look after it. This will get the battery asclose to fully charged as you can.



Detecting current draw by the car. There isa big shunt (a device for measuring current) on the negative battery terminal.It measures what is being drawn by the car and makes adjustments. I know thisbecause I incorrectly connected my first DC/DC charger directly to the batterynegative post. I had real problems. The car ran for hours on 12.3V. No a goodstate. As soon as I move the negative to connection to the earth position theshunt could then detect the current being drawn by the DC/DC charger and thecar compensated accordingly. That would suggest that the D4 can detect current being drawn by any device properly connected.



More soon.

[Tombie]

Good grief....

A DC-DC charger to charge a battery that the alternator will charge anyway... Placing an additional current load above that of the batteries requirement.

Then a switching mechanism (relay) to switch items drawing current (fridge etc) from one power source to the other. That should spike nicely!

All so the battery is charged? Which it will be doing anyway whilst the vehicle is running regardless of the accessories attached (how do you think your main battery works)!

The accessories will "skim" excess power from the same wire...

Biggest enemy is voltage drop in the circuits...

If your alternator is putting out 13v at full steam it's likely that system draw is very low at that time and is being regulated.

Switch on the fridge etc and see if it climbs..

Also, where are you measuring the voltage? And what are you using to measure?

No matter how powerful the alternator, output is limited according to system demands.

The batteries are largely redundant to the system when the vehicle is running....

Voltage = Flow to make something flow (current) you raise the voltage above the object (battery) you are trying to "flow" into (within its functional design limits)

[discotwinturbo]

I am a bit confused about the low voltages the D4 alternator puts out and how this can charge my second battery properly.

Tim (or Tombie) if my second battery was at 50% S of C, what voltage could/should I expect to go into my second AGM battery (with decent cabling) ? Assuming I had the software fix if this was needed.

Brett...

[Homestar]

What a load of crap, while dedicated deep cycle batteries should not be used as starting batteries except in an emergency, there is absolutely no reason why you can not use a cranking battery as a deep cycle battery.

Before any form of deep cycle battery was available for RV use, everybody used cranking batteries as there auxiliary/house batteries and they had no problems.

The primary difference between a dedicated deep cycle battery and a cranking battery when used in cycling applications, is that you get more cycles from a dedicated deep cycle battery than you do from a cranking battery.

But this is why deep cycle batteries are dearer than cranking batteries. But the amount of energy you get from each type of battery is about dollar for dollar the same.

Try getting the correct info before lecture others on a subject you quite obviously don't understand.

Yep, always used cranking batteries as house batteries up until recently as I got them for nothing. Lasted fine for years, with a lot more than 'infrequent discharging'.

[Tombie]

Deep Cycle AGM:- AGM batteries should be charged using a charger with a mode switch for AGM type batteries. It is recommended to use a charger, current limited to 20% or 0.2C of the batteries capacity at a charging voltage of between 14.6 ? 14.8V following deep cycle use, or 13.6V ? 13.8V for standby.

Silver calcium batteries generally require more charging voltage (14.4 to 14.8 V)

[Tombie]

The D4 will not allow the battery to run low.
It may reduce alternator output for short periods however it monitors the vehicles battery during this time and will override if the battery is getting lower.

When you start the vehicle the batteries link and provide a load (demand). If the linked (parallel) battery is below system voltage then the system will up the alternator output to meet the batteries demand and bring the batteries quickly up to its expected level.

Luckily there's another factor in battery charging - temperature.. A battery when charging accepts more current as temperatures rise... At this point a slightly lower voltage is better suited to bringing the battery safely up to charge.

[discotwinturbo]

Deep Cycle AGM:- AGM batteries should be charged using a charger with a mode switch for AGM type batteries. It is recommended to use a charger, current limited to 20% or 0.2C of the batteries capacity at a charging voltage of between 14.6-14.8V following deep cycle use, or 13.6V-13.8V for standby. Silver calcium batteries generally require more charging voltage (14.4 to 14.8 V)

Does my D4 know/do this ?

Brett....

[Tombie]

Yes (if pre-14 or post software update)
The battery is Silver Calcium factory...

[drivesafe]

RoverLander, you have no idea what you are posting up about.

The voltage displayed while the motor is running is a loaded voltage and is the one you need to be able to see how the alternator and battery are working.

If you disconnect the battery and wait, for at least 12 hours, not a few hours, you will then need an OPEN CIRCUIT VOLTAGE TABLE.

Here is a LOADED VOLTAGE TABLE, the correct one to use. This is the only table relevant for RV use, like in your D4.

https://www.aulro.com/afvb/images/imported/2016/06/640.jpg

The monitor on the cranking battery's negative lead can only monitor the current going though the cranking battery.

ALL OTHER NEGATIVE CURRENT GOES STRAIGHT BACK TO THE ALTERNATOR VIA THE BODY, CHASSIS AND MOTOR. it does not go anywhere near the monitor on the negative cable on the cranking battery and as such, there is no way for a D4 or any other vehicle to monitor anything but CRANKING BATTERY CURRENT.

This has already been covered.

[RoverLander]

"Here is a LOADED VOLTAGE TABLE, he correct one to use. This is the only table relevant for RV use, like in your D4"


Please provide a source for this chart and how it works for variable loads on the battery. I cant imagine how a load chart would work unless the load is specified.


The material I read states that the only way to measure SOC through voltage is to leave the battery rest and then measure voltage. The chart you provide is used to indicate that. But it is open circuit and rested.


Also please explain how moving a device drawing power from the negative battery post to the car body results in different behaviour in the car voltage. You seem to be saying that it doesn't make a difference as the car cant tell anything except the cranking battery.

[drivesafe]

"Here is a LOADED VOLTAGE TABLE, he correct one to use. This is the only table relevant for RV use, like in your D4"

Please provide a source for this chart and how it works for variable loads on the battery. I cant imagine how a load chart would work unless the load is specified.
Correct, one needs to know the current load being drawn to be able to get the exact SoC of a battery, but this table is something that can give you a rough idea of the SoC of the battery while you are driving.

As you yourself pointed out, you need to disconnect the battery and let it rest for a few hours.

I would love to see you do that while you are driving.

Folks, my comment above is in jest. Under no circumstances should you ever disconnect the leads from a cranking battery while the motor is running.

This can stuff the alternator and is the one event that can spike electronics in your vehicle.


Also please explain how moving a device drawing power from the negative battery post to the car body results in different behaviour in the car voltage. You seem to be saying that it doesn't make a difference as the car cant tell anything except the cranking battery.
For this one, you need to go and look at the schematics of the D4 to see that the only negative current that can pass the monitor on the cranking battery's negative lead, is the current coming from the cranking battery.

Please show me where any other negative current can go from the body or chassis, up the cranking battery's negative lead, turn round and come back down again.

You do not understand the basics of how electrical circuits work, but you're an expert on how to charge batteries ????????????????

[RoverLander]

"For this one, you need to go and look at the schematics of the D4 to see that the only negative current that can pass the monitor on the cranking battery's negative lead, is the current coming from the cranking battery.

Please show me where any other negative current can go from the body or chassis, up the cranking battery's negative lead, turn round and come back down again."


I think we are saying the same thing. I was saying that any device connected directly to the negative terminal of the battery can not be measured by the shunt on the negative battery cable. Once you move the device's negative cable to the body then the current drawn by the device goes through the shunt and is therefore observed by the car and taken into account in the cars electrical energy management system. My point is that the devices current is visible to the car so the car can do its normal power management.


Still on topic and no disparaging remarks fro me....

[jonesy63]

Yes (if pre-14 or post software update)
The battery is Silver Calcium factory...

Actually, new batteries are AGM Exides, after about 2014. I saw a pile of about 7 dead ones at the dealer a couple of weeks ago, when I was picking up a new bonnet latch/switch. :o

I wonder if these batteries were a symptom of the 12.2V charging schema? :angel:

[Blknight.aus]

Nor can Drivesafe or Blknight understand it, but it is not that complicated really. The requirements of the house battery and the cranking battery are quite different, and hence different types of batteries are used and require different charging regimes.

fairly confident that I've got at least a marginal grasp on different battery technology and its requirements.

I'll offer up the same challenge as I offered up the last DC DC charger advocate that insisted his tech was better.

I'm assuming that you're using a 25 Amp DC dc charger, bring your set up along, I'll bolt in an n70 cranking battery as your start battery, hook up 400AH of flooded lead acid deep cycle batteries drain the starter to 50% soc the house batteries (as you would call them) to 0% soc as in 0V at rest and then we'll start our vehicles.

I dont care what vehicle you use or what size alternator you use to charge the cranking battery but you must use the 25A DC-DC to charge the 400Ah worth of deep cycles.

Im going to use the 35A alternator out of my series and my multi battery hookup system which is stunningly un electronic and makes some relay driven systems seem excessively complicated.

if you've got a 40A DC DC you'll have to let me take ten minutes to bolt in a 50A alternator.

First to fully charged by means of hygrometer testing of the acid in the cells of the batteries wins.

want to bet a house?

once I've gotten settled we can then repeat the experiment using one of these new fangeld D4 alternators we'll again wire up whatever youre using and your 25a or 40a dc-dc charger and I'll just go old school. maybe (since its not going to be my car) even through a traxide unit that the owner can keep afterwards (i figure I'll just bet you the cost of it) and we'll see how you go agaisnt that.

Just FYI... the last dc-dc proponent got of lightly with just the cost of a fuel load and a carton of 5 apples cider.

[THE BOOGER]

Obtain a 14.5 volt regulated supply, connect it to a battery and leave it there.... call me back when the battery stops drawing current.

Yep use them all the time for chargeing alarm batteries the alarm runs from the board seperatly to the bat charge connections and 7.5 ah batteries last about 5or 6 years on average the charge rate drops to less than 50 milli amps so no damage so done:)

[Tombie]

Actually, new batteries are AGM Exides, after about 2014. I saw a pile of about 7 dead ones at the dealer a couple of weeks ago, when I was picking up a new bonnet latch/switch. :o



I wonder if these batteries were a symptom of the 12.2V charging schema? :angel:


Exide AGM are calcium-silver plate :)

[Blknight.aus]

"Here is a LOADED VOLTAGE TABLE, he correct one to use. This is the only table relevant for RV use, like in your D4"


Please provide a source for this chart and how it works for variable loads on the battery. I cant imagine how a load chart would work unless the load is specified.

It uses a time/draw weighted average.

very roughly...

if you're drawing 300 A (thats unrealistic) then the time steps would be very short intervals lets just invent a battery on the spot that takes 10 seconds between each step. when you see that voltage under that load then it tells you where you are (roughly) on your state of discharge under load.

the same battery with only a 30A load might run 100 seconds between each step (not realistic itd be longer due to Peukert's law) with a 3 amp load youd get 1000 seconds between intervls.

you generally dont use a loaded chart to work out the condition of the battery its more an on the fly calculator look up chart for how long you have untill you hit the nominal "flat" voltage. if you then let the battery rest with no load and no charge put on it it will "recover" a little, how much depends on the battery build and condition.

[drivesafe]

I think we are saying the same thing. I was saying that any device connected directly to the negative terminal of the battery can not be measured by the shunt on the negative battery cable. Once you move the device's negative cable to the body then the current drawn by the device goes through the shunt and is therefore observed by the car and taken into account in the cars electrical energy management system. My point is that the devices current is visible to the car so the car can do its normal power management.

RoverLander, I am being 100% serious here, go and study how electricity works.

Your statement is exactly the opposite of what happens.

You are thinking that all negative current has to go to the cranking battery.

This is not the case while the motor is running.

While the motor is running ALL POSITIVE POWER ( current ) comes from the alternator, but for every POSITIVE ( + ) amp that comes from the alternator, there must be an equal number of NEGATIVE ( - ) amps returning.

The NEGATIVE ( - ) amps DO NOT go to the negative terminal of the cranking battery.

If the cranking battery is partially discharged, from starting the motor, and it is pull 10 amps to recharge it, 10 positive ( + ) amps will come from the alternator to the cranking battery's positive ( + ) terminal.

At the very same time, 10 negative ( - ) amps will leave the cranking batteries negative terminal and travel via the cranking battery's negative lead and the battery monitor, to the body of the D4 and then via the motor to the body of the alternator, which is the equivalent of the negative terminal of a battery.

Now lets say you have your sound system cranked up and it is drawing 20 amps.

The 20 ( + ) amps come from the alternator, via the main cable junction at the cranking battery but NOT THROUGH the cranking battery, this 20 ( + ) amps goes to the fuse box, the fuse and then the via the wire loom to the entertainment system.

Because you entertainment system is drawing 20 ( + ) amps, there needs to be 20 ( - ) amps returning to the alternator. So 20 ( - ) amps travels via the body and motor back to the alternator.

The entertainment system's negative ( - ) current never goes anywhere near the cranking battery's negative lead or terminal or the monitor.

So there is no way the D4 knows anything about the 20 amps ( - ) or ( + ), the entertainment system is using.

[drivesafe]

you generally dont use a loaded chart to work out the condition of the battery its more an on the fly calculator look up chart.

Spot on the money!!!!!!!

[Tombie]

[I]"Still on topic and no disparaging remarks fro me....


No.. Just underlying sarcasm masking a blatant refusal to acknowledge the information presented.


We've presented the data, provided reasoning...

Enjoy your Dc-Dc device and all its limitations...

For those with MY14 onwards D4s... If your VIN falls between 698741-726591 then ask for TSB LTB00667v2 to be carried out...

[Tombie]

Pop quiz:

Which direction is the flow of electrons in a DC system?

[SBD4]

http://www.aulro.com/afvb/attachment.php?attachmentid=93846&stc=1&d=1431435137

Simplest way I can put it is with a water analogy (sorry, this crap pic is the best I could do quickly):

Dam = Alternator
water = electricity
Height of water in dam = Voltage
Water Pressure = Current (Higher voltage = higher current)
Toilet = Battery (Cistern actually)
Water pipe = Cable
Two tanks + boy with bucket = DC-DC charger

Scenario one:

The Dam supplies water directly to each of the three toilets.
The Dam level is high so the supply requirement of each toilet can be easily met.
Each toilet will only fill at a rate at which it is capable of and will slow rate of fill as it nears full state of charge.
In this scenario the toilets fill as quickly as the toilets will allow
There is no wasted water due to a lack of inefficiencies in the system meaning that there is spare water to supply other things like the kitchen.


Scenario 2:

The Dam supplies water directly to the main toilet in the house but the other two toilets are supplied by a hard working lad bucketing water from one tank to another.
The lad, while doing his best is slower than the number flushes in toilet 2 & 3 require.
This means they never really get to fill up in time before the next flush
He also spills a lot of water which means he uses a lot more than he would have had the pipe just been connected in the first place.
Because he has spilled so much water, when there is a drought on there is not enough to wash the dishes in the kitchen (accessories)


All toilets will not over charge, they will stop taking water when they are full.

[Blknight.aus]

Pop quiz:

Which direction is the flow of electrons in a DC system?

is that an open to everyone question or do you want someone specific to answer the question.

[Tombie]

is that an open to everyone question or do you want someone specific to answer the question.


I would expect you to know it... :)

[Eevo]

Pop quiz:

Which direction is the flow of electrons in a DC system?

clockwise in the southern hemisphere
anticlockwise in the northern hemisphere

be careful when crossing the equator

[RHS58]

clockwise in the southern hemisphere
anticlockwise in the northern hemisphere

be careful when crossing the equator

LOL
One of your better responses.
Ta.

[Homestar]

Pop quiz:

Which direction is the flow of electrons in a DC system?

Am I allowed to answer?

Oh well, too bad if not... :angel:

Negative to Positive. ;)

Electrons are negatively charged so are attracted to the positive and repelled from the negative when a circuit is connected.

[Tombie]

:D done this before perhaps Gav.. :)

One would think you may know a thing or 2 about electrickery :)

Only magic in electrical theory is how to keep the smoke from popping out the insulation...

[Homestar]

I would hope into line of work that I understand electricity by now. :D

Lucas never worked out how to keep the smoke in.

[Eevo]

Electrons are negatively charged so are attracted to the positive and repelled from the negative when a circuit is connected.

or, an alternate point of view (just to screw with your head like my lecturer did):

electrons are negative, therefor they must be travelling to the negative terminal (and possibly congregating), otherwise it wouldn't be negative would it now.



think about it for a bit.

[Eevo]

or....
if thats the negative terminal, the electrons are moving away, and so it will become positive in short order.

:whistling: :wasntme:

[bee utey]

or, an alternate point of view (just to screw with your head like my lecturer did):

electrons are negative, therefor they must be travelling to the negative terminal (and possibly congregating), otherwise it wouldn't be negative would it now.



think about it for a bit.
Yup. For about 0.03 seconds, realising we're talking about current here not static electricity. :)

[drivesafe]

I currently am running a Traxide dual battery system, though with regular charging trhough my ctek mx5.0 I'm still suffering problems with keeping the voltage up (some of you may remember my earlier posts) :o

Hi mijango, have you got any progress report on your charging problems.

[Eevo]

Yup. For about 0.03 seconds, realising we're talking about current here not static electricity. :)

no no, works for a circuit too

[p38arover]

Lucas never worked out how to keep the smoke in.

No need, they came up with a fix: Lucas Replacement Smoke Kit (http://www3.telus.net/bc_triumph_registry/smoke.htm)

https://www.aulro.com/afvb/images/imported/2015/05/922.jpg

https://www.aulro.com/afvb/images/imported/2015/05/923.jpg

Most of the electrics on a P38A are, I believe, Valeo who, unfortunately, haven't released a smoke replenishment kit as yet

[BigJon]

Most of the electrics on a P38A are, I believe, Valeo who, unfortunately, haven't released a smoke replenishment kit as yet

When I worked at a dealer we were convinced that Valeo was French for Lucas.

[p38arover]

When I worked at a dealer we were convinced that Valeo was French for Lucas.

I thought the same - 5 letters......... :p :(

[jonesy63]

Exide AGM are calcium-silver plate :)

Mike - you missed the point of that post... 2014-on had Exide AGM, and there was a pile of dead ones at the dealer... coincidence? Hmmm ;)

[Tombie]

Mike - you missed the point of that post... 2014-on had Exide AGM, and there was a pile of dead ones at the dealer... coincidence? Hmmm ;)


Possibly - until the TSB...

[mhewitt]

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.

[Tombie]

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.


Electron flow would elude to that :)

[letherm]

After ploughing through 21 pages of this, I wonder if some people are overlooking the fundamental law of electricity - it sucks, it doesn't push.

Ah!! That's why it doesn't fall out of powerpoints when the switch is turned on.
:wasntme:

[ytt105]

Ah!! That's why it doesn't fall out of powerpoints when the switch is turned on.
:wasntme:


Thank you. That's worried me all my life!

[Mungus]

Food for thought regarding the 12.2V system voltage reported. (other than the TSB previously mentioned)
It appears the 'Battery Monitoring System' will periodically deplete the battery voltage as part of it's self calibration. An extract from the workshop manual.




BMS Control Module Self Calibration

Periodically the BMS control module will initiate a self-calibration routine. To self-calibrate, the battery monitoring system first charges the battery to its full condition.

NOTE:If the vehicle is only driven for short periods the charging process could takea number of days to complete.

Once the battery is fully charged, the BMS control module will discharge the battery to approximately 75% of its full state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.

When the second part of the routine has been successfully completed, the BMS control module will return the battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on battery condition, temperature and loading.

The BMS control module also monitors the primary battery condition with the engine switched off. If a low voltage condition is detected the BMS control module can request the infotainment system is switched off to protect battery voltage.

[drivesafe]

BMS Control Module Self Calibration

Periodically the BMS control module will initiate a self-calibration routine. To self-calibrate, the battery monitoring system first charges the battery to its full condition.

NOTE:If the vehicle is only driven for short periods the charging process could takea number of days to complete.

Once the battery is fully charged, the BMS control module will discharge the battery to approximately 75% of its full state of charge, but never lower than 12.2 V. The time taken to complete this part of the routine is dependent on the electrical load on the vehicle.
Hi Mungus and thanks for that info.

I'll lay good money on that process being the route cause of the problems many D4 owners are having, where their D4 runs the battery discharge part of the process and then fails to reset the operating voltage levels of the alternator to the correct running levels required to charge and maintain the cranking battery.

In every case I have been involved with, where there has been a problem with continuos low voltage operation, as soon as the upgrade is carried out, the D4's voltage levels instantly rise to the high 14v levels.

This is a clear indication of a software problem and not a problem with the D4's alternator or anything else in the vehicle.

Also, as this discharge and test procedure is a periodical test, would point to why many of these constant low operating voltages just suddenly happen in vehicles that have otherwise been working fine.

I would suggest any owners of late model D4s should keep an eye on their operating voltage to see if they end up with this problem.

Continual low operating voltages like this will stuff the cranking battery, and while it is not an owner cost while under warranty, it could be very expensive outside warranty.




When the second part of the routine has been successfully completed, the BMS control module will return the battery to its optimum level of charge. The optimum level of charge will be between 12.6 V and 15 V, depending on battery condition, temperature and loading.

This part also clearly indicates, without any question, that under normal operation, the BMS DOES NOT ( SHOULD NOT ) allow the voltage to drop bellow that of a fully charged battery, contrary to some of the claims made earlier in this thread.

[Mungus]

Hi Drivesafe. I posted that up to show that periodically, vehicles fitted with the BMS will discharge the battery down to a low level. I thought people checking their system voltage may believe they have an issue if they happen to chance their test during this self calibration period. As you and Tombie have said, there is an issue requiring a software upgrade for vehicles in the following VIN range as per TSB LTB00667v2. Discovery 4 / LR4 (LA)
Model Year:
2014
VIN:
698741-726591

[drivesafe]

Hi Mungus and you are correct but it is not likely that most D4 owners will ever notice ( UNDER NORMAL OPERATIONS ) that their battery has been discharged down to 12.2v.

The procedure in the info you posted up, will take about 30 minutes of continuos driving to discharge the battery by 25%.

Or as stated in the info,

NOTE:If the vehicle is only driven for short periods the charging process could takea number of days to complete.


NOTE, the battery will not be at 12.2v for 30 minutes. It will most likely only be there for less that a few seconds to maybe a minute.

The point is, the battery does not remain at 12.2v for any length of time.

This is not what is occurring in the D4s that are having problems. Their operating voltage level remains at a constant 12.2v, and this is a major problem when it happens.

[RoverLander]

I have been observing the voltage for the past several months.


It only drops down to 12.2v after the battery has been well charged and then if goes down to 12.2v when cruising or going up a hill. If you cruise constantly (without taking your foot of the accelerator) it can stay at 12.2v for quite a while. I have seen it last for at least 10 minutes while cruising on the M7. It will then jump up to 12.5v even though you are sill cruising.


As soon as you coast or go down a hill the voltage will jump up to anywhere between 13.1 and 14.9.


It is not completely consistent. I do the same trip everyday and I see 12.2v several times a day but not always under exactly the same circumstances. It never happens when coasting.


I wish I could taking a video so I can show you :)


Can anyone publish the content of the TSB. I don't know how to get TSB data.

[drivesafe]

I wish I could taking a video so I can show you :)

Hi Peter and you don't have to take a video to convince me that your voltage readings indicate that your alternator is operating at 12.2v.

The point is, if the reading is being taken from your battery terminals, then you have a problem that, if not fixed, will stuff your battery.

If the voltage reading is being taken somewhere other than at the battery's terminals, then the readings themselves are irrelevant, because of the effects of voltage drop that will commonly occur on any circuit running through your vehicle ( or in any vehicle ).

Furthermore, as has already been stated, running a DC/DC device off a battery that is not being charged at the correct voltage, will just help to shorten the battery's life span.

[discotwinturbo]

RoverLander, you are getting voltages better than mine when the car decides to charge, and my D4 is an MY12, which according to LR Southerns is performing perfectly.

The highest I have seen is 14.2 averaging much lower in the low to mid 13's when she charges.

Brett....

[drivesafe]

The highest I have seen is 14.2 averaging much lower in the low to mid 13's when she charges.

Brett....

Hi Brett, and what is your lowest operating voltages?

EDIT:- Also Brett, where do you get your voltage measurements from?

[Mungus]

Can anyone publish the content of the TSB. I don't know how to get TSB data.



An extract from TSB LTB00667v2. A subscription to Topix is well worth the coin IMO.

Only refer to the electronic version of this TechnicalBulletin in TOPIx.

SECTION:414-00

Battery WarningMessage Displayed On The Instrument Cluster

AFFECTEDVEHICLE RANGE:

Discovery 4 / LR4 (LA)

Model Year:
2014
VIN:
698741-726591

CONDITIONSUMMARY:

NOTE: If the DTC B1404-13 'charging system opencircuit' and or B1479-72 power supply distribution box actuator stuck open' isnot stored in the GateWay module, continue with SDD diagnostics with referenceto TOPIx workshop manual.

Situation: A customer may report a concern thatthe battery warning lamp/battery warning message intermittently displays on theinstrument cluster or the Eco stop start may not function.

This version has been issued for a change to theAffected Vehicle Range, Section and Condition Summary.

Cause: GateWay Module (GWM) software issues. Suggested Customer Concern Code MU3.

Action: Should a customer express concern,follow the Service Instruction outlined below.

[discotwinturbo]

Hi Brett, and what is your lowest operating voltages? EDIT:- Also Brett, where do you get your voltage measurements from?

12.4....mostly hovered around 12.9. The app I use allows me to record the whole time while it was running, so I could then watch each period of recording each evening.

I use the OBD port. I don't get the low voltage warning on the display that others seem to have.

Brett...

[drivesafe]

NOTE: If the DTC B1404-13 'charging system opencircuit' and or B1479-72 power supply distribution box actuator stuck open' isnot stored in the GateWay module, continue with SDD diagnostics with referenceto TOPIx workshop manual.


OK now this is something that needs more info.

I only have a basic knowledge of the ECO STOP/START system, but is the reference to "charging system is open circuit" talking about the cranking battery, which I suspect it is not, or is it referring to the STOP/START battery.

NOTE, one of the ways to deactivate the ECO STOP/START function, is to disconnect the negative lead on the STOP/START battery.

This is literally creating an OPEN CIRCUIT situation, which is virtually the same as what is started the Land Rover documentation.

Again, RoverLander, can you post up where you are taking your voltage readings from.

As above, if they are not at the battery, they are irrelevant, and if they are at the battery, then according to Land Rovers own Documentation, courtesy of Mungus, your D4's battery voltage is too low ( not normal ).

[drivesafe]

I use the OBD port.

Thanks Brett, unfortunately I have not as yet managed to find out where OBD tools source the voltage data from, the ECU or at the battery?

[LandyAndy]

I have been observing the voltage for the past several months.


It only drops down to 12.2v after the battery has been well charged and then if goes down to 12.2v when cruising or going up a hill. If you cruise constantly (without taking your foot of the accelerator) it can stay at 12.2v for quite a while. I have seen it last for at least 10 minutes while cruising on the M7. It will then jump up to 12.5v even though you are sill cruising.


As soon as you coast or go down a hill the voltage will jump up to anywhere between 13.1 and 14.9.


It is not completely consistent. I do the same trip everyday and I see 12.2v several times a day but not always under exactly the same circumstances. It never happens when coasting.


I wish I could taking a video so I can show you :)


Can anyone publish the content of the TSB. I don't know how to get TSB data.

From monitoring mine I can say what you have is a normally functioning charge system.
I have a ciggy lighter monitor.The smart charging system in these D4s only charges when it needs to and when economical to do so.So when you are off throttle yes the volts go way up,put your foot on the loud pedal and then they drop to the 12.6 or so.
Now,run a 80lt Engel on freeze,plus the headlights on,AC etc,etc,mine sits at 14.8V all the time.When its full it reverts to only charging at full voltage on the over-run.There may be a slight difference in monitoring at the ciggy lighter,but over several months of the same its close enough.
Mine falls within the vin numbers listed,and I do get that low battery warning when parked up in the shed for some time.
Service coming up,will see if there is any change with low battery warnings after the upgrade.
I have a one of Tims dual battery systems installed.Sofar has performed really well running the engel on 3 holiday trips.With the D2 I had to resort to plugging a Ctek in overnite.Havent had to with the D4.YET
Andrew

[SilvaD4]

NOTE, one of the ways to deactivate the ECO STOP/START function, is to disconnect the negative lead on the STOP/START battery.

From what I have read about the eco stop starts systems (like that used on the Freelander II - Land Rover Launches Start-Stop Equipped Freelander 2 TD4_e In Australian Market | The Motor Report (http://www.themotorreport.com.au/38882/2010-land-rover-freelander-2-td4e-startstop-now-available-in-australia)) is that they use the main cranking battery (i.e. there is no separate STOP/START battery)

[shanegtr]

There can't be that much of a fuel economy gain by doing these weird charging methods can there?

[Tombie]

There can't be that much of a fuel economy gain by doing these weird charging methods can there?

Predominantly European Emissions... Where the difference of 0.005% can mean a significant cost saving to the owner...

[drivesafe]

From what I have read about the eco stop starts systems (like that used on the Freelander II - Land Rover Launches Start-Stop Equipped Freelander 2 TD4_e In Australian Market | The Motor Report (http://www.themotorreport.com.au/38882/2010-land-rover-freelander-2-td4e-startstop-now-available-in-australia)) is that they use the main cranking battery (i.e. there is no separate STOP/START battery)

Hi Silva, I know nothing of the setup in a Freelander, but the Eco STOP/START system in the D4 is located in the auxiliary battery box on the driver's side of the engine bay.

In with the electronics is a small battery. The setup is very similar ( if not the same ) as in the new RRS.

[Mungus]

In an D4 Stop/Start vehicle, the Dual Battery system isolates all power supply to sensitive electrical components/systems which may be affected by low voltage from the primary battery due to the Tandem Solenoid Starter motor operation and supplies them with power from the secondary battery when an engine start is in progress. The Primary battery is used exclusively to supply the TSS motor and essential power required for engine starting. The Power Supply Distribution Box uses two banks of MOSFET's to change the supply into two separate circuits when an Eco Start is required.

[drivesafe]

In an D4 Stop/Start vehicle, the Dual Battery system isolates all power supply to sensitive electrical components/systems which may be affected by low voltage from the primary battery due to the Tandem Solenoid Starter motor operation and supplies them with power from the secondary battery when an engine start is in progress.

This would probably explain why the STOP/START function is deactivated when the negative lead is removed from the STOP/START battery.

The system can,t find the second battery so rather than risk sensitive system being interrupted, the STOP/START function is deactivated.

[Fluids]

Our Impreza has the STOP/START feature (feature!!??) ... also has a "disable" button on the dash. Why not do the same for the D4 ? No traffic lights were we live so the S/S feature can get a bit annoying ... that said, before you can get the clutch pedal to the floor the engine has restarted ... it's very quick.

The Impreza trip computer has a start/stop time activated display ... 2.5Hrs each way trip to Sydney saves us approx' 20-25min each way ... that's almost 1Hr saved on a 5Hr trip ... 20% ... not to be sneezed at ...

... however, me thinks there's a corresponding reduced life of the starting battery and starter motor ... time will tell.

Car only uses one battery (cranking).

[Mungus]

The Impreza trip computer has a start/stop time activated display ... 2.5Hrs each way trip to Sydney saves us approx' 20-25min each way ... that's almost 1Hr saved on a 5Hr trip ... 20% ... not to be sneezed at ...

Car only uses one battery (cranking).

That's a cool function. Whilst it's not actually 20% saving of fuel usage, it is still 40-50minutes less idle.

[drivesafe]

I'm a bit sus about some of the claims about how much fuel is saved with the STOP/START function.

To have the motor stopped for up to 20% of a trip ( Subaru add ), you would be sitting at traffic lights or in traffic jams for a hell of a long time.

Then once out on the open road, there would be no advantage.

One thing I do like about the Subaru version of the STOP/START operation is that you can turn it off at any time.

A few makes now have STOP/START operation, but they are either permanent or can only be deactivated when you first start your trip.

I noticed that some of the VWs have two switches, one to deactivate the STOP/START for that trip and one to deactivate the function permenately.

[Fluids]

The amount of fuel saved is only that which is consumed during idling ... very little.

You have to have the front wheels pointed straight ahead, gearbox in neutral, and clutch out ... if the A/C (climate control) is on after a while depending on the cabin temperature the engine will restart as it see's fit. As fast as I can get the clutch in and select 1st gear the engine is started and running ... certainly doesn't hinder a quick getaway from the lights.

That 20-25min saved each way I quoted was pretty much ALL after we entered Sydney's outer urban areas and started encountering traffic lights ... not uncommon to sit at lights for 2-3min when it's busy ... do that 5 times and there's 15min!! .... easy to do 5 times (and more) from Sydney's outer edges into the city centre ... especially in peak hour.

The function, if disengaged, remains off until you stop the car and remove the keys ... automatically re-engages every fresh start.

For where we live the fuel saving is neither here nor there but the extra wear & tear on the starter battery and starter motor are the concern.

What's worse ... extra emmissions from extra idling time, or the extra emmissions from re-manufacturing starter batteries and starter motors more frequently ??

[PhilipA]

Ah yes but it allows them to claim better fuel economy numbers, and also to claim lower emission numbers in Europe, which has a big bearing on rego costs.
That is most probably why you cannot permanently disable the function as it is an emission reducing feature.

I guess my main thought on this and the variable voltage thing is that they could have made the D3/D4 much more economical by reducing the weight by 300- 400Kg as they have now done with the Range Rover and Sport. But it was a quick and dirty design which was wildly successful for them so who can argue?

But I wonder how long until LR get to the stage like with Prius in USA where I can recall reading of many faults that no dealer can fix because of the complete computer control of the car. I mean even the D2 has the bloody indicators going through the BCM. Why?

I was also thinking about the new Ingenium engine and how they have used roller bearings in the cam, offset crank etc , and the homogenized EGR. All this friction reducing stuff has been known for 50-100 years ( well maybe not EGR) but was always too expensive. ( except maybe for Honda where my old N600 and the 1300 had a roller crank in the 60s)
I will bet it will be harder to disable the EGR on an Ingenium!

So I guess it will go until it doesn't then you throw it away. It will be interesting to know whether the next generation of Disco will have an Ingenium and whether you will have to take off the body to change a turbo. I bet not as one of the stated aims of the Ingenium was to minimise special tools and enhance serviceability. Maybe LR have learned something from feedback about the absurdity of having to remove the body for service items. Maybe it is costing them a bomb for warranty!

Regards Philip A

[Blknight.aus]

the current tech of stop start is precursive to the next level.

augmented drive is the way of the futer for now and companies are experimenting with their tech to make it all work.

the next generational development of vehicles will see us all with the flywheel, starter and alternator replaced with an all in one unit thats inverter driven.

all o it less to do with how muh it costs you to run the vehicle and more of it to do with the emissions. essentially all the benefits we see will be side effects of the car companies trying to beat emission rules.

I for one will not be having a bar of it. I'll still be dogding all of it by running proper mechanical linkages fed on anything I can get into the pump that can impersonate something oily and combustible. Of course, I'll still be fixin the new tech I just wont be driving it.

my bet is the near future we will be able to obtain self contained inverter driven bushless starters to replace ones that burn out from stop start drive. At this point we're all going to look back at the simplicity of threads like this one and wonder why we were all so tizzed up about it.

b

[drivesafe]

What's worse ... extra emmissions from extra idling time, or the extra emmissions from re-manufacturing starter batteries and starter motors more frequently ??

Thank you Fluids, this has been my argument against these new emission reduction features for some years now.

STOP/START may be fine in city driving, but as fluids posted, we are yet to see the long term effects of these functions on vehicle parts and lets face the truth here, Land Rover, for one, does not have a particularly good record when it comes to reliability.

But I suspect we are going to see quite a few makes having problems with some of the potential failures these things may develop, but worse still, they have not been round long enough to see if any potential faults are actually life threatening, and I am not just talking about Land Rovers, I mean all makes have yet to prove how fail safe each system is going to be after a few years of use.

And all this is supposed to help reduce exhaust emissions, but from everything I have read, this is only based on the amount of reduction at the time the compliance plate is fitted to the vehicle.

Not once have I seen, as Fluid pointed out, a Dust to Dust analysis of the total emission created while making the ORIGINAL and any REPLACEMENT parts for STOP/START systems.

[shanegtr]

even if the starter motors are beefed up to cope long term with the stop/start engines, how much of a PITA are they going to be when the engines themselves start getting older and dont start as quickly as they used to:p

[clubagreenie]

What I don't understand is that in the past mechanical devices were built and put into place (motor/pump units for example) that once fitted could never be replaced and they have continued (with maintenance) to run for decades and we can't make a starter (just an elec motor after all) last the life of a car?

I've only killed one starter, as it stayed engaged after starting. Boy did that smell bad after runnning engaged for a couple of hours at god knows what RPM. Many have died through "natural" causes (planned failure)

[DiscoMick]

Been playing with the stop start on our new Mazda 2 auto. If you lift the foot slightly off the brake pedal it restarts. Mazda sold us a six year warranty so they must think the stop start starter will last at least that long.

Sent from my GT-P5210 using AULRO mobile app

[Blknight.aus]

even if the starter motors are beefed up to cope long term with the stop/start engines, how much of a PITA are they going to be when the engines themselves start getting older and dont start as quickly as they used to:p

not going to be a problem guys the life of type for the vehicle this tech is fitted to is shorter than the life of the gear fitted.

Who these days wants to be in last years model when you can have tomorrows car today and get an extra shoe holder i to the bargin.

[shanegtr]

not going to be a problem guys the life of type for the vehicle this tech is fitted to is shorter than the life of the gear fitted.

Who these days wants to be in last years model when you can have tomorrows car today and get an extra shoe holder i to the bargin.
Me because I dont want to spend the $$ on a new car. The most I've ever paid for a car is $27K. My daily run around for work under $5K

[Blknight.aus]

Me because I dont want to spend the $$ on a new car. The most I've ever paid for a car is $27K. My daily run around for work under $5K

you sir do not fit our business model and therefore your opinion is of no value to us....

wait till you hear that from a market researcher

[DiscoMick]

We just set a limit of $100pw and financed the wife's Yaris, which we've just rolled over for a Mazda 2. Vehicles are a terrible investment which lose up to half their value in their first three years, so I regard the financing as like renting. Why sink many thousands of $s upfront into something which is a woeful investment?
That said, we did pay cash for the Defender because we intend to keep it forever. Horses for courses.

Sent from my GT-P5210 using AULRO mobile app

[shanegtr]

you sir do not fit our business model and therefore your opinion is of no value to us....

wait till you hear that from a market researcher

Excellent, I like to be abnormal so that suits me just fine :p

[Stuart02]

slightly back on topic, here's a thing

Alternator Output Compensator | Piranha Offroad 4WD Products (http://www.piranhaoffroad.com.au/news/index/article/35)

They don't say exactly how it works but given it's a replacement fuse I'm guessing it just tricks your alternator into thinking it needs to work a bit harder?

[Tombie]

slightly back on topic, here's a thing

Alternator Output Compensator | Piranha Offroad 4WD Products (http://www.piranhaoffroad.com.au/news/index/article/35)

They don't say exactly how it works but given it's a replacement fuse I'm guessing it just tricks your alternator into thinking it needs to work a bit harder?

Its a Diode in a fuse casing - a Diode drops 0.6v fooling the alternator into running 0.6v higher.

Will not work on our vehicles..

[drivesafe]

Its a Diode in a fuse casing - a Diode drops 0.6v fooling the alternator into running 0.6v higher.

Will not work on our vehicles..

Spot on the money.

The Land Rover voltage monitoring system is far more advanced and this diode will not force an increased voltage in a Land Rover.

Furthermore, the Alternator Voltage Booster Fuse was invented and developed by a guy in Melbourne, who sells them for around half the price Piranha are flogging theirs for.

If you have a Toyota 4x4 or friends with one, and want to improve the charging, this is the guy to contact.

HKB Electronics (http://www.hkbelect.com/)

[RoverLander]

From monitoring mine I can say what you have is a normally functioning charge system.
I have a ciggy lighter monitor.The smart charging system in these D4s only charges when it needs to and when economical to do so.So when you are off throttle yes the volts go way up,put your foot on the loud pedal and then they drop to the 12.6 or so.
Now,run a 80lt Engel on freeze,plus the headlights on,AC etc,etc,mine sits at 14.8V all the time.When its full it reverts to only charging at full voltage on the over-run.There may be a slight difference in monitoring at the ciggy lighter,but over several months of the same its close enough.
Mine falls within the vin numbers listed,and I do get that low battery warning when parked up in the shed for some time.
Service coming up,will see if there is any change with low battery warnings after the upgrade.
I have a one of Tims dual battery systems installed.Sofar has performed really well running the engel on 3 holiday trips.With the D2 I had to resort to plugging a Ctek in overnite.Havent had to with the D4.YET
Andrew





I agree Andrew, all is normal in my car. I have not had one low battery message and I think the Battery Monitoring System and Software is running as per standard.


I have done some more testing with the DC/DC charger connected and disconnected. No difference. I have also let the second battery run down (12.3 no load) and then charged it with the DC/DC charger. The car voltage seemed to stay higher while the DC/DC charger was running (25amp draw). I don't think I saw 12.2v while that was happening but I want to do some more testing.


In any case, I am happy with the state of things. I will post here if my main battery does cark it before 4 years. I replaced the battery in the last car (MY10 D4) after 4 years of DC/DC charging. Not because there was a problem, but because I was heading around Aus and didn't want the possibility of having a battery problem.

[drivesafe]

Hi again Peter and sorry mate, but you still don't understand how YOUR system works, let alone how D4 systems in general work.

If your D4's voltage drops to 12.2v, while driving, you will not get a low battery warning.

If your cranking battery is below 12.2v before you start your motor, and the battery is in a poor condition, then you will get a "LOW BATTERY, START MOTOR" message.

Or if there is a software problem ( which is what has been happening ), you can still get the "LOW BATTERY, START MOTOR" message, even when the battery has been independently fully charged.

As to testing your system by having the DC/DC charge the battery from 12.3v ( 70% SoC ). This is not a test because all you are doing is topping up a partially discharged battery and once the battery gets to about 75 to 80% charged, the DC/DC device will start reducing the charge current, so not long after you started your motor, the D4's voltage is pretty well irrelevant.

If you want to get a realistic idea of whether your setup is working or not, next time you know you are going to be driving for at least 4 hours, discharge your battery down to 11.58v ( 20% ) and then see how long your D4's voltage remains high.

[alpick]

Feeeyoo

that took a while

🙄

[haydent]

Just wanted to share my current predicament/experience putting a DCDC in my caravan.

Bought a 30A Victron, (in hindsight prob have just got a 20A, but wanted that bit extra and didnt think too much about the wiring consequences)

Glossed over the misleading "50A Rating" on narva "6MM" that id previously run on the car side for last caravan that had just been running a fridge, appx 10amps.

Was in a rush to leave so thought this was fine, having forgot about 'voltage drop with current'. Had tested the DCDC 'worked'(was connecting) but never tested it at high current as the van was charged from not being used.

Turns out that 6mm (4.58mm2) wire is grossly undersized. And I needed B&S 6 for this distance. The van side had B&S 8 so that was not so bad.

But after the first night of "off grid" started the car and it came up reduced performance / gearbox fault, iid errors P0191=23 (fuel pressure signal stays low) P0089-2F (fuel pressure signal erratic) U2023-86 (TCM bus signal is invalid)

The errors reminded me of when i had a loose battery terminal, so figured it was electrical related, and disconnected the DCDC breaker, (rated at 50A) there is also a VSR. And the errors stopped that morning.

But in the days and weeks/months following on a big caravan trip it still happens, even with the DCDC & Loom not connected (i upgraded the car to B&S 6 after the initial errors, and realising it wasnt working with the 6mm wire (too much voltage drop) used it a few times to charge but kept it disconnected when not needed)

These will always go away by restarting the car, but sometimes the come back several times within a minute, generally in the mornings, once warmed up and driving they generally dont happen.

Thought it might have been the battery (century stop/start agm), but had it tested ok, and even replaced it, which didnt help (luckily could returned the battery, sca)

So now thinking it could be the alternator, as have checked terminals and connectors, the alternator is putting out full rating according to IID, though im going to test with clamp meter on order to see if it really is putting up what it says, as commonly in the mornings its doing 100 to 160A+ amps for the first few minutes after starting in morning.

This errors have come up plenty of times, but once and only once i did get an alternator error (i didnt record the code), something about excitor field voltage or something.

[drivesafe]

Hi hydrant and first off, what type of batteries are you using in your caravan?

Next, because of the way your SMART alternator works, you would have been far better off running 6B&S ( 13.5mm2 ) instead of the 8B&S ( 7.9mm2 ) cable.

This is because of Voltage Drop caused by your SMART alternator. Current is not an issue.

Next, can you check and make sure there is no additional cabling connected to the NEGATIVE ( - ) terminal of your cranking battery as this can cause similar problems to the ones you are having.