My next project dual battery [Archive] - Australian Land Rover Owners

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HAK

24th June 2008, 08:03 PM

WildOne

24th June 2008, 08:34 PM

I can recommend the SC-80 Battery controller supplied by traxide, contact Drivesafe on here if you want some info or good advice on what works and what does'nt.

mcrover

24th June 2008, 08:43 PM

Yep I agree, Traxide or Pirahna, not sure of the models but they are both really good and easy to wire in, I know one of the Pirahna units will do 3 dissimilar (sp?) batteries.

drivesafe

25th June 2008, 08:13 AM

I’m planning on going a dual battery system in my D2 Im thinking of going even a third battery for future camper trailer, 2nd and third battery all included kit put together including battery box and better gauge cable all exept the batteries it will cost me $380 not bad ah

What do you think?

Hi Chronic, $380 for an “idiot” switch set up seems quite dear.

If you list exactly what your after I think you will find you can get a dual ( triple ) battery system, including an intelligent controller for around that price.

Redback

25th June 2008, 09:07 AM

I’m planning on going a dual battery system in my D2 Im thinking of going even a third battery for future camper trailer looking at the kit pieces to this Projecta kit http://www.projecta.com.au//documents/item/340 so I went to this site http://www.naauto.biz:8080/naauto/catalogue/category104/category106 2nd and third battery all included kit put together using the same as the Projecta set including battery box and better gauge cable all exept the batteries it will cost me $380 not bad ah

What do you think?

Mate go the Traxide unit from Drivesafe, easy too install and works very well, Tim is also a top bloke, if you have any questions just ask him he's very helpful.

I have the SC40.

http://www.traxide.com.au/DBS.html

Baz.

5teve

25th June 2008, 09:40 AM

Yep just installed an sc40 on the Boat to charge 2 separate circuits (aux and crank) and works great.. nice small unit.. and comes complete to connect everything up.. i even ended up getting the cables and all other stuff from Drivesafe (traxide) top stuff that made the job a little easier than it could of been (full rewire of the boat)

Thanks

Steve

mrapocalypse

25th June 2008, 10:10 AM

neil 90

25th June 2008, 10:15 AM

Hi chronic, ive just fitted a sc-40 from traxide, top unit and can highly recomend them. ive added a battery monitor from jaycar to keep an eye on the charge and battery condition. much more accurate than a load of led's and only $35 .....bargain!

Redback

25th June 2008, 10:24 AM

And put the battery in the cargo Area..... Mine just died in the engine bay after about 9 months and careful maintenance with a heat shield. Even on a V8. You might need to cut some plastic though!

And go the SC80. Easy and works well.

Ian.

What battery did you have, i've had my auxillary battery next to the turbo for just over 2yrs now, D2s don't like lead acid batteries, main or auxillary, i fried my Exide lead acid in 4mths.

This is a good way too have your batteries
V8
https://www.aulro.com/afvb/images/imported/2012/04/939.jpg
TD5
https://www.aulro.com/afvb/images/imported/2009/09/1036.jpg

Baz.

Corgie Carrier

25th June 2008, 08:06 PM

I fitted a Piranha BDE150 10 years ago and was told my batteries were just about dead, well they lasted another 2.5years. I replaced them with a 735cca sealed starter and a 135 amp/hr deep cycle and have just replaced them since easter (7.5yrs).

I have never had a problem with starting the truck and am about to buy another one for my new project.

I know they are expensive ($320 for the DBE180) but spread that over 10+ years and it works out cheap.

My 0.02c worth

Neale

HAK

25th June 2008, 08:10 PM

here go's

3 x PLT1BAT Pilot Light Red with Battery Symbol $4.50 (Each)

I was going to install these some where on the dash to indicate when the system is on and which of the 2 batteries are switched on

9268

1 x 24401 Solenoid C'over 12V 85/35A C/Duty 6 Terminal $50.00 (Each)

this unit to do what it does

Solenoid change-over.
Voltage: 12 volt
Rating: 85/35amp
Duty: continuous
Other: 6 terminal

9265

1 x 00B&S-B Cable 00 B&S Black $13.50 (Metre)
8 x 00B&S-R Cable 00 B&S Red $13.50 (Metre)

Single Core Cable 00 B&S with Black Insulation.
390amp, 64mm sq, 798/0.32 strand

2 x RWB662 Battery Box Large $18.00 (Each)

protect the battery in the boot I dont know how that would go with LPG :eek: if I go that way

9266

1 x MA98304 Antizap Surge Protector H/Duty (2 to 00B&S) $57.00

for the obvious

Antizap surge protector heavy duty 12/24 Volt (2 to 00B&S Cable).

9267

3 x 61040 Switch Battery Isolator 12V 1000amp $17.50 (Each)

isolate one battery and use the other and vise verser

9269

and so on and son

4 x MA14HDN Battery Terminal H/Duty Neg Wingnut $6.00 (Each)
4 x MA14HDP Battery Terminal H/Duty Pos Wingnut $6.00 (Each)

10 x SC50-12 Cable Lug 12mm Hole x 9.5mm Shank $1.50 (Each)
10 x SC50-8 Cable Lug 8mm Hole x 9.5mm Shank $1.30 (Each)
10 x SC25-10 Cable Lug 10mm Hole x 7mm Shank $0.70 (Each)

SUBTOTAL $389.50

tell me what you think I was vering this way as the Pahrana kits are like $900 are they

drivesafe

25th June 2008, 09:50 PM

Hi Chronic, I’ll go through your post bit by bit, ignore anything ( or everything ) I post if it does not suit your requirements.

Your “Battery On” indicator lights. From experience based on test modules supplied to a number of my customers, lights in the dash that indicated the operating state of the control module ( showing if it was on or off ) were useful for about a fortnight and then the lights became a noisiness ( and ALL were removed )

Solenoid = no comment at this stage ( see below ).

00B&S cable is overkill. This size cable will NOT cause any problems but the cost and the amount of work to install it for the very little advantage it gives over thinner cable ( 6B&S will achieve just about the same results ) really makes it a bit of a waste of money.

Battery boxes = good price.

Surge and spike protectors are, in my opinion, the equivalent to putting a condom over a condom, ( pardon the crude equivalent but it does give you an accurate idea of how they work ).

All electronic devices have their own built-in surge and spike protection and the fact that you never hear of people, who don’t have these devices fitted, having mass failures of electronic device, caused by spikes or surges, should be convincing enough to show they are just not needed.

Battery Switches, depends on weather you have a specific need to isolate the batteries from one another during use.

Using an automated dual battery controller eliminates the need for having to have and use battery switches ( and more importantly having to remember to use them, hence the name “Idiot Switch” ) and means no need for a separate solenoid.

Below is a kit I now have but I just haven’t had time to put it up on my web site. It’s a bit cheaper than yours ( $325 ) but offers a lot more. You will still need to get the two battery boxes.

Cheers and hope this is of some help.

https://www.aulro.com/afvb/images/imported/2008/06/59.jpg

https://www.aulro.com/afvb/images/imported/2013/06/1370.jpg

https://www.aulro.com/afvb/images/imported/2008/06/60.jpg

The CWK-3B Kit includes the following parts.

1 x SC80 Dual Battery Controller

9m x 6B&S TWin Sheathed cable

2.5m x RED 6B&S cable

1m x BLACK 6B&S cable

3m x 20mm Split Tube

3m x 10mm Split Tube

1 roll of Black Automotive Electrical Tape

3 x Saddle for mounting Split Tube

2 x 50 amp Anderson Plugs, Dust & Safety Cover

1 additional Safety Cover

1 x Anderson Plug Handle

1 x 50 amp Cole Hersee Circuit Breaker

2 x 30 amp Cole Hersee Circuit Breakers

2 x Battery Terminal Clamp Set

7 x 5mm Cable Eye Terminals

7 x 8mm Cable Eye Terminals

2 x 10mm Cable Eye Terminals

2 x Yellow 5mm Eye Crimp Terminals

1 x metre of 2.4mm Resin Core Solder

Heat Shrink = 9 x Red, 6 x Black, 2 x White

10 x Wire Ties

drivesafe

26th June 2008, 07:49 AM

BTW most of the TRAXIDE kits now have the installation instructions supplied on a CD.

This has allowed me to put much more info in the instructions and pics to make the installation easier.

Redback

26th June 2008, 08:28 AM

Treads

26th June 2008, 09:26 AM

Your “Battery On” indicator lights. From experience based on test modules supplied to a number of my customers, lights in the dash that indicated the operating state of the control module ( showing if it was on or off ) were useful for about a fortnight and then the lights became a noisiness ( and ALL were removed )

I use my led lights all the time (combined with a voltage meter on the dash with a switch for monitoring charge state of each battery).
https://www.aulro.com/afvb/images/imported/2008/06/201.jpg

If the green light is on all is good in the world of electrickery :cool:

drivesafe

26th June 2008, 10:41 AM

Hi Justin, with a manually operated system you need to have an indication to let you know when you have to do something.

The whole point of an automated system is that it’s fit and forget, so there is no need for an in-dash indicator.

Cheers.

trobbo

27th June 2008, 03:03 PM

Bit of a hijack,
Drivesafe, I run one only battery in my vehicle. it is a dry cell battery. In my camper I have a wet cell battery. The camper gets used 1 or 2 times per year. Ordinarily I do not have a need for a dual battery management system, but may need one while the camper is attached. What are your recommendations. I do not any any circuit breakers or surge protectors installed. I do have 50 amp fuses located near the positive terminal of each battery (so there are 2 fuses in the wire running positive power from the vehicle to the camper).

drivesafe

27th June 2008, 03:29 PM

Hi troddo, what sort of things do you run while you are away and how long do you stop in one location at a time.

trobbo

27th June 2008, 05:34 PM

Kerry

28th June 2008, 09:44 PM

Some input to the discussion in the hope it helps.

Firstly - Cronic, I wouldn't go with your original 'solenoid' option. Charging a battery through another battery isn't a good idea. I am also interested to see the diagram for the Traxide system - it also appears to do the same, as the alternator wire still goes to the main battery.

I will stand corrected on all this, but I have over 30 years of aux battery experience and it has taken me a long time to sort the shortfalls out.

Consider this - you have your fridge and lights operating for an extended period with the aux battery isolated. The aux eventually gets well run down. (It is important it doesn't get TOO run down or it will be damaged, so your system should have a low voltage cut-out on the aux side - important!) So if you check the electrolyte specific gravity of both batteries with a hydrometer, the main will be OK, but the aux will be low. When you start the vehicle and the batteries re-connect, the alternator will charge hard for a short time till the voltage in the system rises, then the alternator eventually goes into float mode. At this point only a low amperage is going into the system. If you drive ALL day, the aux might be fully charged at the end - but if you only drive a few hours, the sg of the aux will not be max. It takes a LONG time to get that aux fully charged through the main battery, even though the voltage of the system looks good. It is not the voltage that charges, it is the amps.

The system required is one that puts charge DIRECTLY to the aux - not via the main. The Traxide doesn't appear to do this - but I can only go by the diagram.

My system? - the manual marine switch and a low voltage cut-out. I can run both of my batteries together till my 60litre Trailblaza won't start - but my Tdi 300 Defender still will! These switches have 3 poles - one for each battery and one output. They have 4 positions - 'Battery 1', 'Battery 2', 'Both' and 'Off'. Swing the starter cable, alternator cable and ALL aux cables to the output pole, connect each battery to each other pole and you have 100% control over your system. Another problem with aux batteries is that they don't get used enough - they don't get enough work and gunk up. With this system, you can leave the switch on 'both' and both batteries get work when starting and get charged together - they are always at the same state of charge, same age, same make and model (you can get good advice on battery types - these days there are models that can crank AND deep cycle), so they die at the same time. When you camp, you have the option of using one battery for aux, then switch to the other to start (if necessary), then back to the discharged one to give it DIRECT charge.

The new super battery isolators will direct charge to the aux battery I am assured, but the aux still sits unused in between trips and is sure to let you down when you least want it to.

(At this point, I step off soapbox)

drivesafe

28th June 2008, 10:02 PM

I have very little load at the moment. A usual trip is to drive 3 - 4 hours, base camp for up to 3 - 4 days at a time and then return. We did do a trip to Fraser Island earlier this year.

I run a 40ltr engel and a couple of 12 volt fluro lights off the camper so it has very little load.

Hi Trobbo, if you did a bit of running around on Fraser ( as one does ) then there should be no real problem with just unplugging the camper when you get there and as long as your auxiliary battery is keeping everything running, I wouldn’t change a thing, it obviously works for you.

drivesafe

28th June 2008, 10:33 PM

Consider this - you have your fridge and lights operating for an extended period with the aux battery isolated. The aux eventually gets well run down. (It is important it doesn't get TOO run down or it will be damaged, so your system should have a low voltage cut-out on the aux side - important!) So if you check the electrolyte specific gravity of both batteries with a hydrometer, the main will be OK, but the aux will be low. When you start the vehicle and the batteries re-connect, the alternator will charge hard for a short time till the voltage in the system rises, then the alternator eventually goes into float mode. At this point only a low amperage is going into the system. If you drive ALL day, the aux might be fully charged at the end - but if you only drive a few hours, the sg of the aux will not be max. It takes a LONG time to get that aux fully charged through the main battery, even though the voltage of the system looks good. It is not the voltage that charges, it is the amps.

Hi Keery, sorry mate but a battery’s charging capability is directly effected by the VOLTAGE applied, not the current.

You can have a 1,000 amp alternator but if it is not putting out a high enough voltage, at least one volt higher then the battery’s SoC, then the battery will not charge.

Next, an alternator can not tell if there are batteries of different states of charge connected to the system and even using your analogy of having a fully charged cranking battery on-line and this supposedly would cause the alternator to think that any battery connected to the system, was fully charged.

The hole in this theory is that the best quality battery, at 100% State of Charge ( SoC ) has a voltage out put of, at very best, 12.9 volts but is usually 12.7 to 12.8 volts and this is over a volt below the average regulator’s setting of 14 to 14.3 volts. So as you can see, the actual SoC of any or all of the batteries will have no independent control over the alternator as the alternator will always be putting out a higher voltage than any of the batteries have, that are connected to it.

Putting it very crudely, the way a vehicle’s electrical system works is all based around the joint operation on the alternator and the voltage regulator.

The regulator sets the voltage level of the system and the alternator produces enough current to keep the voltage up to that level, which in turn, automatically supplies enough current to cover the current draw of any devices that are connected to the system.

If an extra device is added to the system, like turning on your headlights or air conditioner or if a control device connects an additional battery to the system, the systems overall voltage level will drop.

As soon as the regulator / alternator set up detects the slightest drop in vehicle voltage, the alternator immediately starts to produce more current to get the voltage back up to the set regulated voltage.

The greater the load applied to the system, in other words, the more things turned on or connected to the system, the greater the voltage drop, the higher the current output of the alternator will be.

The amount of current produced by the alternator is directly proportionate to the voltage drop being detected.

The operation of any vehicle’s electoral system is basically as simple as that.

There is nothing high tech about how the system works, such as monitoring everything connected to the system.

The alternator / regulator set up has absolutely no way of knowing what is connected to the system and drawing current, they just work together to try to keep the vehicle’s common voltage at a pre-set level.

Just to give you an example of how your theory is actually the opposite of what really happens, the new Discovery 3 and Range Rover Sports have what is probably the most advanced electrical monitoring system of any 4x4s on the road today.

Their system is set up so that if the system detects that the continuos current draw is higher than what the alternator can maintain, the system starts to shut down high current devices such as the air suspension compressor, the sound system and so on.

The idea is that the engine management system is given priority over everything else, so as to allow these vehicles to get home.

One of the side effects of this system is that conventional dual battery controllers can causing incompatibility problems with these vehicles and the vehicles are shutting down air suspension compressors and so on and making the owner think the system has failed when the system is actually working exactly how it’s designed to.

Even with the advanced electrical monitoring that these vehicles have, they still have absolutely no way of knowing what is causing the additional current draw, they just act accordingly as does your vehicle and everybody else’s, in there own way.

One more point, because the battery is monitored independently, any dual battery system that disconnects the cranking battery in a D3 or Range Rover Sports will cause heaps of supposedly unrelated problems because the vehicle’s power monitoring will see that the battery’s voltage is lower than the alternator’s output voltage and the vehicle’s computers will go into overdrive trying to charge the battery.

Cheers

trobbo

1st July 2008, 03:37 PM

Hi Trobbo, if you did a bit of running around on Fraser ( as one does ) then there should be no real problem with just unplugging the camper when you get there and as long as your auxiliary battery is keeping everything running, I wouldn’t change a thing, it obviously works for you.

And there I was assuming that I was going to be told that I needed to buy something.

Thanks for the confirmation that my set up doesn't require me to live on mars because I dont have every last gizmo that the big shops sell.

BTW I was out camping for 3 days on the weekend with fridge and lights running. The reconditioned auxillary battery in the camper retained all but .02 volts of the charge that it had when we set up camp. :)

Redback

1st July 2008, 04:58 PM

And there I was assuming that I was going to be told that I needed to buy something.

Thanks for the confirmation that my set up doesn't require me to live on mars because I dont have every last gizmo that the big shops sell.

BTW I was out camping for 3 days on the weekend with fridge and lights running. The reconditioned auxillary battery in the camper retained all but .02 volts of the charge that it had when we set up camp. :)

My only suggestion would be a small solar panel, say 15 or 20watt, i'm running a very similar setup to you, i have 4 lights a water pump and use the camper to charge cameras and the like.

It's not essential but it will give you the option of lengthening stays in the one spot by 2 or more days, which is what it has done for us, our panel is 20 watt, so no regulator required which keeps the cost down and all i do is when we setup camp i connect the panel direct to the camper battery with alligator clips, stick the panel in the sun and she's working to trickle charge the battery.

Just a thought

Baz.

Bundalene

2nd July 2008, 09:36 PM

Hi, I feel that Kerry makes a few good points. One about low voltage protection. If an average battery is fully flattened it is damaged to some degree. Some of the better AGM batteries can be flattened a number of times without detriment. As he indicates the Trailblazer fridge cuts out on low voltage.

Secondly, with the switching arrangement as suggested also works well. This allows the flattened battery to be charged by isolating the other battery. Hella make a 350 amp continuous fully sealed 2 battery switch as suggested for a reasonable price. This set up allows for parallel batteries in winching situations and also simple battery isolation for mainterance. It requires a bit of discipline to isolate one battery for an exterded stay. I agree that battery isolators have their place but they are only a small part of the total scene. Cheers, Erich

drivesafe

2nd July 2008, 10:11 PM

Hi Bundalene, first off as you have pointed out, in a manually operated set up, you require, as you put it, a bit of discipline. The problem is that you can not afford to forget once, to set the switch correctly or you will, as you also pointed out, you will most likely damage one, if not both batteries battery.

Because of the way the traxide controllers work, the chances of damaging your auxiliary battery(s) is dramatically lowered and your cranking battery is always protected.

Next, why do you need to isolate one battery while charging another, with exception to vehicles with small alternators, 45 or 55 amps, there is no advantage to doing this and even with a small alternator, if you don’t isolate the batteries, it only means that it will take a little longer to charge, which is going to be the case weather isolate or don’t isolate, it’s the size of the alternator that governs this..

Remember, you only have to forget once and the cost of replacing a battery, because of a premature demise, is going to cost you more than if you fitted one of my controllers in the first place and they don’t forget.

Cheers.

Bundalene

2nd July 2008, 10:43 PM

Hi, you use the word "you" loosely. I use Odyssey batteries which can be discharged many times - used to be 500 times and fully recharge in 1 hour if the current can be supplied. I also have a Trailblazer fridge which when it cuts out through low voltage and this still allows me to start the car. Thirdly I carry a Christie Engineering Honda battery charger when away for an extended time. There are many battery options. Cheers, Erich.

drivesafe

3rd July 2008, 04:51 AM

Hi, you use the word "you" loosely. Erich.

I have absolutely no idea what that is supposed to mean but if it suits, I’ll refer to certain people in the third party if YOU like.

To obtain the amount of power some people need they seem to go to extraordinary lengths to do so and I might add extremes in cost. If this is what they want so be it.

BUT!

In most cases, people setting up a dual battery system usually do it on a basis of fit and forget. The last thing they want have to do is play electrical substation manager when they could be just sitting back and enjoying their holiday.

This is the prime aim of an automated dual battery controller.

Each unto his own.

Redback

3rd July 2008, 08:02 AM

Well i'm all for set and forget, i remember having the isolation switch in the Disco, on our Simpson trip i forgot too isolate and paid the price of flattening both batteries.

Luckly for me i had a jumper pack and that got me started in the morning, cause Cadelga Ruins isn't the most popular place and also because of the rain around most of the roads were closed.

That was July 05, when i got back i purchaced a Traxide SC40 and a new battery, installed them and have never touched them since:BigThumb:

Baz.

Kerry

16th July 2008, 10:54 PM

I'll have one more go at this, then shut up. My experience in this matter doesn't cover RRs and D3s - I am sure they have a more sophisticated system than my Defender.

Drivesafe's comments are probably based on a different set of needs than mine. I spend a week or more on Gulf rivers at a time keeping my beer cold and my barra frozen, so I watch my batteries carefully. I have a generator and chargers that take my batteries to a higher level of charge than my alternator seems to achieve. I have also watched my mate's dual battery systems fail as mine used to do - now they have manual systems. We all have had aux battery troubles due to bad advice.

Following are more of my understandings and observations for 'normal' 4WDs.

- yes, as Drivesafe says, the voltage of the charging system is what triggers the alternator to top the battery up, but that is also where it all falls down. It has to be higher than the battery to overcome the internal resistance and higher again to get the amps to flow. The alternator goes into 'trickle' charge long before the battery is [U]fully[U] charged. At around 14.1V, the cells in an open battery will begin to gas, and that is about when the charge drops to trickle. (Sealed batteries behave differently, but follow the same path). Otherwise the battery would boil dry on a long run. I understand the battery is less than 80% charged at this point and few batteries get charged beyond this level.

- so back to my original argument, trying to charge a discharged battery through a charged one exaggerates the problem. Once the alternator gets the system voltage up to (say) 14.1V, it goes into trickle mode. That doesn't mean the discharged battery has caught up with the main battery - it hasn't. A hydrometer will prove that. But putting the charge [U]directly[U] to the discharged battery will improve the situation substantially. The alternator regulator will be detecting a lower voltage.

- so if you camp for a couple of days and drain the aux, then drive just a couple of hours to the next spot, the aux will be far from charged unless the charge is going direct. Even then it will be a lot less then 100% - your charge voltage would have to reach 15.7V+ to achieve that.

- aux batteries always fail when you are on holidays!

- a cranking battery has a different internal resistance to a deep cycle battery, another reason to treat them separately.

- alternator regulators have temp voltage compensation and will charge at even lower voltages on hot days.

- if the Traxide was between the alternator and the batteries and sending charge either or both ways, I would have more confidence in it, but between the batteries, to me, suggests it can't do the full job unless it has some method of holding the voltage lower to trick to alternator to keep pumping amps.

i'm off!

drivesafe

17th July 2008, 09:10 AM

Hi Kerry, unfortunately you have a misunderstanding of how batteries and alternator/regulators work.

But before going there, there is one situation where one battery will charge while the other does not get much of a charge and this only occurs when the cable used to connect all the batteries together is way too thin or and this is in the same vain, if either of the batteries has a poor earth.

I’ll start with the way a battery is charged and this is a very crude explanation.

To charge an automotive battery and this applies to flooded wet cell, gel cell or AGMs, there needs to be a chemical reaction inside the battery and this reaction needs a voltage applied to the battery that is higher than the battery’s State of Charge ( SoC ).

So if a battery has an SoC of say 12 volts and an external voltage 12.1 volts is applied to the battery’s terminals, the chemical reaction will start BUT to get the chemical reaction to a point where it will actually start to store power in the battery, the applied voltage MUST BE at least 1 volt higher than the battery’s SoC other wise with an applied voltage of less than one volt above the battery’s SoC, the voltage is just burn off by the chemical reaction.

This need to have a charge voltage of at least 1 volt higher than a battery’s SoC or the charge voltage is wasted is why when you connect two batteries with different SoC, in parallel, the higher charged battery discharges down to the same SoC as the lower charged battery while the lower charged battery’s SoC doesn’t change.

Also, any charge voltage of less than 1 volt higher than the battery’s Soc will not only not charge the battery but the lower the charge voltage is the more chance there is that this charge voltage will not stop the battery from self discharging, but more on that later.

Once you have a charge voltage which is more than 1 volt higher than the battery’s SoC, the chemical reaction will now be strong enough to get the battery to start absorbing power.

Next, the higher the charge voltage the quicker the battery will charge ( if the current is available ) but their is an upper limit to just how many volts can be applied to a battery.

A very rough comparison would be like stopping a vehicle, with an automatic transmission, at a set of traffic lights located on a steep hill. If you don’t give the engine enough gas, the vehicle will roll backwards, this is like applying too low a charge voltage to the battery, it will still self discharge.

If you give the engine just enough gas to hold the vehicle on the spot, this is like applying a charge of about 1 volt high than the battery’s Soc, the battery won’t charge but it won’t discharge. This is the same reason a 240 vac battery charger applies a float charge to a battery, to stop it self discharging once it has been fully charged.

When the lights go green, you give the engine more gas to get the vehicle going and the same with a battery, apply enough voltage and the battery will start to charge.

The more gas the faster you go, the more voltage applied the faster the battery will charge.

Now as I said, that is a VERY crude comparison

Back to reality, there is an upper limit to the amount of voltage you can safely charge a battery with and this limit varies from one type of battery to another. Gel Cell and most AGMs should not receive a charge voltage of more than 14.4 AT ANY TIME, while flooded wet cell batteries can tolerate charge voltages up to 15+ volts but only for short periods of time and should normally never have a constant charge voltages higher than 14.7 volts.

In both cases, the reason for not taking the charge voltages above 14.4 for Gel Cell and AGM batteries and 14.7 for flooded wet cell batteries is that they will start to gas.

While standard flooded wet cell batteries can have the water topped up if they are caused to gas, any Sealed batteries, such as Maintenance free, Gel Cell and AGM batteries, will be damaged if they start to gas.

That’s the crude basics of automotive battery charging, now to the alternator.

Some alternators do have temperature compensation but once the motor is warmed up, the alternator will be at it’s normal operating voltage and this will be no less than 13.8 volts

Most alternators are not SMART devices and as such don’t give a damn about how charged or discharged a battery is, they are just designed, in conjunction with the regulator, to keep the vehicle’s voltage at a pre-set level. That’s it, nothing more and nothing less.

It’s this pre-set level that gets people on the wrong line.

If a vehicle’s normal operating voltage is 13.8 or higher, it will FULLY charge an automotive battery, how fast the battery gets to fully charged is governed by how much higher the vehicle’s voltage is above 13.8 volts.

If a battery is half charged ( or discharged ), it will have an SoC of about 12 volts, so if your vehicle has an operating voltage of 13.8, it’s more than a volt above the battery’s Soc and as such, the battery will be charging while the motor is running.

As the battery recharges the bulk of it’s charge and it’s SoC approaches the 12.6 or 12.7, the voltage difference is so close to the minimum required to keep the chemical reaction strong enough to cause the battery to absorb power that the final topping off of the battery to get it to fully charged will literally take hours of driving.

On the other hand, if the vehicle’s pre-set voltage is 14 to 14.2 ( the average voltage of most vehicles ) the battery(s) will not only have their bulk charge replaced quicker, it will take much less driving time for the battery(s) to reach a fully charged state.

Kerry, as to your last section.

- if the Traxide was between the alternator and the batteries and sending charge either or both ways, I would have more confidence in it, but between the batteries, to me, suggests it can't do the full job unless it has some method of holding the voltage lower to trick to alternator to keep pumping amps.

It is the very nature of the way my Traxide controllers work as to where they should be installed but that’s a whole other subject.

mrapocalypse

17th July 2008, 10:26 AM

As a traxide user, I just want a simple solution to run fmy fridge for a few days on straddy, if I am throwing that big marine switch over between 1st 2nd or both batteries, at some stage am i going to have NO voltage so settings like radio and clocs and whatever els will be erased? or am i going to have 24 volts in the system for that split second.

I run a volt meter off my second battery that is in series from the sc80, it always seems to maintain the 13.9-14.4 volts while I'm running, .... so where does the bit where the batteries tell the alternator that there's enough charge in the system, the Alternator always seems to be running the same voltage?

The only thing that kind of worries me is that because the D2 has a small tray in the engine bay - my batteries are very different sizes, and I kind of worry that my main battery is trying to hold the second battery up... For paranoia sake (And this is no bad reflection on the TYRAXIDE) I am thinking of placing an isolator between the main and aux baattery, but then I would have done my dough on the traxide in the first place! I think I would like the TRAXIDE to just automatically Isolate the 2nd baattery when the engine is not running or something liek that so it just runs as a charging system. Overall though I am pretty happy with what I have!

drivesafe

17th July 2008, 11:37 AM

Hi mrapocalypse, in actual fact, when using an SC40, or as in your case, an SC80, the cranking battery is holding up ( supporting ) the auxiliary battery and this is where these two controllers differ from every other controller on the market.

The SC40 and SC80 are specifically designed to allow up to half of the cranking battery’s stored capacity to be used to supply additional power for running accessories.

There are a host of other advantages to the way the SC40 and SC80 work, and not just the additional time you can go before needing to charge up again.

The main advantage to these or any automated dual battery charge controller is still the fact that they automatically protect the cranking battery from being flattened.