On-Line auto electrical info

[drivesafe]

Hi folks, I have decided to put together an auto electrical info section, to be posted up on my website, and it will be a free download.


The need for this type of info has come about because of the many times the same questions are asked about the same subjects, but in different threads, at different times.


While I am quite happy to answer those questions if I have experience with, the problem is that I am now so busy I am finding it hard to reply to questions post here, and to the many e-mails I get.


My intention is to compile an online book and as new subjects are added, you will be able to down load the latest version at your leisure.


For now I am posing two questions here. The first is for subjects that people would like to know about.


The second question is for suggestions for a name for this online book?

PLEASE NOTE, the questions can be about me gear or just about general auto electrical info.

I will be posting up info like the correct way to carry out a jump start, or how to wire batteries in parallel and series, and so on.

If I use data from someone else, I will post up a credit for where the info came from.

Please ask away!

[SPROVER]

I think that is a great idea. I think definitely dual battery set ups and solar. Solar panel set ups always have me perplexed. Lol.

[drivesafe]

Solar is a good startup subject to cover and while I will need to outsource the info on most areas, I do have many years of hands on experience of using small unregulated solar panels for charging and maintaining batteries and will post up the info I have.

One area I think I will start with, is how to use a digital multi meter ( DMM ).


I find many people would benefit greatly when fault finding, if they had and knew how to use a DMM.


I am also considering making some basic videos, BUT, in this area, I will need the educating.

[pop058]

Excellent idea Tim and I think teaching the great unwashed (me included) how to do basic fault finding and use some test gear can only be a good thing

[Ranga]

Thanks Tim - how about understanding SoC and battery capabilities?

[mr_squiggle]

How about some information on basic fault finding (half split etc), common causes of circuit failures such as loss of earth & what to look for.
Soldering basics is another one that I see common errors in too.
Happy to contribute if you want.

[drivesafe]

Hi mr_squiggle, ( and anybody else ) please feel free to contribute to this thread.


I will have final say as to what goes in to me web page “book” but as I stated, I will be giving credit to who ever supplies info used in the "book".

[Mick_Marsh]

Probably worthy of a book in itself but what about when a DC/DC charger is appropriate, and when it is not.

[austastar]

Hi,

Design Guide for 12V Systems – Dual Batteries, Solar Panels and Inverters | outbackjoe (https://outbackjoe.com/macho-divertissement/macho-articles/design-guide-for-12v-systems-dual-batteries-solar-panels-and-inverters/)

Cheers

[Eevo]

Hi,

Design Guide for 12V Systems – Dual Batteries, Solar Panels and Inverters | outbackjoe (https://outbackjoe.com/macho-divertissement/macho-articles/design-guide-for-12v-systems-dual-batteries-solar-panels-and-inverters/)

Cheers

wow,thats pretty complete!

[weeds]

Hi,

Design Guide for 12V Systems – Dual Batteries, Solar Panels and Inverters | outbackjoe (https://outbackjoe.com/macho-divertissement/macho-articles/design-guide-for-12v-systems-dual-batteries-solar-panels-and-inverters/)

Cheers

Very good link......covers a hell of lot.

[drivesafe]

Hi folks and the type of “info” in that link is the very reason I want to post up an information section both here and on my web site.


There are a lot of errors in the info at that link, and these are errors that someone working in the industry shouldn’t make.


For instance he states that an older type battery chargers should only be used for a maximum of 48 hours.


Sorry, these sorts of battery chargers should be constantly monitored and removed from the battery as soon as it is charged.


These old type chargers are not properly regulated and will just continue to raise the voltage being applied to the battery and can cook and destroy a battery in as little as an hour or so.


And his reference to putting a switch in the wiring between a battery charger and the battery otherwise “the charger may SINK some of the current whilst turned off and flatten your battery”


It is an industry standard to leave battery chargers, solar regulators and even DC/DC device, all connected to a battery at all times. They will not discharge the battery, unless the device is actually stuffed in some way.


Another statement “Many generators have a 12V output which can be used to charge batteries”. The 12V output on a generator is a POWER SUPPLY intended for running things like 12v lighting and the likes. It was never intended for charging batteries.


Again, he demonstrates his genuine lack of any real knowledge of this industry when he talks about alternator voltages, where he thinks they need to run at 13.8v or the batteries will be damaged.

Many older vehicles had constant operating voltages of around 14.3v and all you D4 owners, when charging low batteries, you will often see 14.7v, and this can last all day long as you drive, and none of you have cooked any of your batteries.


As shown above, there is a need for accurate auto electrical info.

[rocket rod]

Tim great idea the guide you putting together. You could call it "Power to the People".

As far as topics, what you have suggested is a great start, what about what wire, connectors, fuses etc to use when installing DIY accessories. When to solder or crimp, what tools do you use for such jobs etc.

I like your reply to "information" found on the web as per the link above. I'm always hesitant to believe most things I read about including what's written on this forum unless the author states their experience and qualifications to make such statements. I have no problem with people sharing their experiences, that's valuable and entertaining and it's what this forum is about, but readers always need to be cautious accepting the info as gospel.

[drivesafe]

Hi Ron and the amount of errors in the info in that link is a shame because the guy has done an excellent job of explaining some of the topics, he just has not got the info right.


Again, it’s a shame because he has done a very good job of it otherwise.

[Eevo]

Hi Ron and the amount of errors in the info in that link is a shame because the guy has done an excellent job of explaining some of the topics, he just has not got the info right.


Again, it’s a shame because he has done a very good job of it otherwise.

-
i would argue that 80-90% of his content is correct and give people a good idea of what to look for.

[weeds]

I guess it all about research....comparing articles and making a decision.

Tim has always given/shared his knowledge what is great but if you don't know him at the end of the day it's just another online document

[Don 130]

Thanks Tim, you've come up with a great idea. I'm keen to see the DMM tutorial. Another thing I'd like to have a better understanding of is, solar regulators. where in the system they perform best and how to select the best type(MPPT?).
Don.

[Ranga]

How about a layman's short guide to relays?

[drivesafe]

Hi Ranga, here is some basic info about different types of automotive relays.


This is info I already have available, but if there is more you would like to know about them, just ask.


https://www.aulro.com/afvb/images/imported/2017/04/1030.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1031.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1032.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1033.jpg

[Ranga]

Thanks Tim, can you explain to me and others why relays are used?

[bee utey]

The most important reason to use a relay is so that the path between a high current source (battery and alternator) to the load is as short as conveniently possible. Voltage drop along a cable is directly proportional to its length so if you double the length you need to double the cross sectional area to maintain the same voltage loss. Short fat cables are cheaper than long even fatter cables.

Secondly removing high current cables and connections from confined spaced reduces the heating effect of high current, also the possibility of fire if a connector fails on a high current wire.

Thirdly it takes the high current load off the switch gear, which in Land Rovers is often barely capable of carrying its rated current, e.g. head lamp switches.

Fourthly, if your relay is controlled by electronics, eg your ECU, it makes sense to keep high currents away from the ECU and manage them externally. A relay is simple to replace, an ECU that's fried is often very expensive and time consuming to replace.

Fifthly, if you have a number of high current devices at a distance from the main power source (e.g. at the rear of your vehicle), they can share a single large power feed cable and need only thin control cables for each function controlled by a relay. It's simply economical to save on heavy copper cabling which is now very expensive.

[AK83]

Thanks Tim, can you explain to me and others why relays are used?

Or more importantly why a company(such as Toyota!! on their '04 Rav models) don't use a relay to power the headlights!

The switch is one of those turn-ey type indicator stalks, and the contacts inside eventually burn out, which results in the extra expense of having to purchase an indicator stalk when one really only wants a headlight switch .. which should have been a relay anyhow!

May have to wire up a couple of relays into the lighting system to prevent future occurrence.

[Eevo]

Or more importantly why a company(such as Toyota!! on their '04 Rav models) don't use a relay to power the headlights!

The switch is one of those turn-ey type indicator stalks, and the contacts inside eventually burn out, which results in the extra expense of having to purchase an indicator stalk when one really only wants a headlight switch .. which should have been a relay anyhow!

May have to wire up a couple of relays into the lighting system to prevent future occurrence.

wow,i didnt know that

[AK83]

wow,i didnt know that

neither did we(brother in law and I)
Spent close to an hour looking for the relay for the headlights(as both not working) only to 'give up' and google it.
Found out that there are no relay(s) for headlights .. and so all power is to switch.

brother in law changed switch now, headlights OK(for now).

[mr_squiggle]

Or more importantly why a company(such as Toyota!! on their '04 Rav models) don't use a relay to power the headlights!

The switch is one of those turn-ey type indicator stalks, and the contacts inside eventually burn out, which results in the extra expense of having to purchase an indicator stalk when one really only wants a headlight switch .. which should have been a relay anyhow!

May have to wire up a couple of relays into the lighting system to prevent future occurrence.

Anyone old enough to remember the foot switch would know that's how it was in the "old days". Relays weren't common, most switches used to handle full device current.

[bee utey]

Anyone old enough to remember the foot switch would know that's how it was in the "old days". Relays weren't common, most switches used to handle full device current.

And driving barefoot on hot nights meant you burnt your big toe on the dip switch.[bawl]

[AK83]

Anyone old enough to remember the foot switch would know that's how it was in the "old days". Relays weren't common, most switches used to handle full device current.

Love!!! the old days.
My dad's Caddies had those foot switches .. interesting idea they were.

I started with Rover cars before the RRC(and now D1).
Maybe 10 P6's early 2000's to a '76 V8, brother had a 3lt P5, and after my P6 epoc, I then got into SD1's('76 - '84).

I remember spending most of a day on my bro's P5 removing all the switches(the flip type IIRC ??) opening them up and using a small points file to clean up the green and black build up on the copper contacts.
Nice strong, solid copper. They made a strong, resounding click! sound when flipped.
Todays plasticky switches have no soul about them.

I quickly learned that to minimise the cost installing yet another bloody switch relays had to be installed(even before the roadworthy was booked in).
I reckon I could eventually wire up the relays to the headlights blindfolded, I'd done so many.

Can't remember if the ('79) RRC had relays for headlights or not. I was just an automatic process. Get another Rover and I just installed them, irrespective .. for my own piece of mind.
I was sold some relays with built in fuses(as I remember) and they gave me trouble in that the fuses(30A, on 30A relays) would blow for no reason.
I used to use one for low-beam and one for hi-beam(55/75's I think).
I eventually replaced them for the non fused types and had no trouble after that. To this day(30odd years later) I still avoid the relays with built in fuses from that experience.

So, yeah.. back in the day not having relays for heavy current devices/switches was normal. But nowadays it makes no sense.

[austastar]

Hi,
Early Moris Minors didn't even have a relay on the starter motor.
Pulling the starter switch cable drew the small gear on the starter into mesh with the teeth on the flywheel to full engagement, then put power onto the cranking circuit.
Cheers

[drivesafe]

OK folks, I’ll start a Digital Multi Meter ( DMM ) tutorial in the next week.


But first, make sure you have a DMM handy.


This is just a suggestion, if you need to buy one, there are some very cheap and useful DMMs but if you think you might get some use and want a little better than basic, Altronics have a DMM for $45 ( Q1134 ) and this one has a handy advantage over most.


Most DMMs have a maximum current limit of 10 amps, but this one can handle up to 20 amps and this is a more useful limit when measuring circuit currents around a vehicle.


Anyway, I will start putting something together and see how we go.

[pop058]

OK folks, I’ll start a Digital Multi Meter ( DMM ) tutorial in the next week.


But first, make sure you have a DMM handy.


This is just a suggestion, if you need to buy one, there are some very cheap and useful DMMs but if you think you might get some use and want a little better than basic, Altronics have a DMM for $45 ( Q1134 ) and this one has a handy advantage over most.


Most DMMs have a maximum current limit of 10 amps, but this one can handle up to 20 amps and this is a more useful limit when measuring circuit currents around a vehicle.


Anyway, I will start putting something together and see how we go.


Pic for those looking at this DMM [smilebigeye]

Q1134 Auto Ranging Digital Multimeter - Altronics (http://www.altronics.com.au/p/q1134-auto-ranging-digital-multimeter/)

120404

[drivesafe]

THE CORRECT PROCEDURE FOR JUMP STARTING


First off, jumper leads do not need to made with huge cables. 6B&S ( 13.5mm2 ) is the most convenient cable size but cabling as thin as 8B&S ( 7.8mm2 ) will easily jump start a vehicle with a flat battery.


Also, you do NOT need suppression type jumper leads. These are nothing more than a salesman’s con job.


Whether the crippled vehicle’s battery is flat or faulty, it will still hold a surface charge, even if that is for just a few minutes. When jump starting a vehicle, you don’t need it to hold that surface charge for more than a few seconds.


The correct procedure for jump starting a vehicle is as follows.


Bring the donor vehicle as close as practical to the crippled vehicle.


Leave the motor running in the donor vehicle at all times.


If you turn the motor off in the donor vehicle and connect the jumper leads, while you will not flatten the donor vehicle's battery, you can cause a sufficient drop in the voltage of the donor vehicle’s battery that the motor can not be started without disconnecting one of the leads.


Make sure the PARK BRAKE is applied in both vehicles.


Turn the ignition off and remove the kew from the ignition of the crippled vehicle. This is not done to protect the vehicle’s electronics, this is done to remove any remaining current draw from the crippled vehicle’s battery.


Many vehicles can draw quite high currents with the ignition key still in the switch ( up to 40 amps ).


Note, in many new vehicle, not until you remove the ignition key will all current loads be turned off and in some vehicle, like new Land Rovers, the computers will remain active for up to 3 minutes, while they go through shut-down routines, after the key is removed.


With Keyless Entry type vehicles, make sure the vehicle’s ignition is off and take the key away from the vehicle.


Next, connect the positive lead to the crippled vehicle’s positive ( + ) battery terminal, then connect the other end of the positive lead to the donor vehicle’s positive ( + ) battery terminal.


The POSITIVE Lead is connected first as a safety precaution. If your to drop the Positive lead while trying to connect it to the donor vehicle, you will nor cause a short.


If you were to connect the NEGATIVE Lead first and dropped the POSITIVE lead as you were trying to connect to the donor vehicle’s battery, if this lead can in contact with any metal parts on the donor vehicle, there could be a considerable short.


Next, connect one end of negative lead to the donor vehicle battery’s negative ( - ) terminal.


You MUST NOT connect to the crippled vehicle battery's negative ( - ) terminal.


This again is for safety reasons. If you have been cranking the motor trying to start is with a flat battery, or if the battery dropped a cell while you were driving and you stopped the motor, say to fuel up and then went to try to start the motor again.


In these situations, the battery will most likely have been gassing. When you connect up the last lead, it will complete the circuit and can regularly cause a spark as you make the last contact.


If you connected to the crippled vehicle’s negative ( - ) terminal on the battery, there is a chance you could ignite the gas coming from the battery, causing the battery to explode.


PLEASE NOTE, if a battery does explode, it will NOT vaporise the vehicle, it will simply spray electrolyte around the engine bay, and a quick wash down with a hose will remove the electrolyte.


The danger posed if you connect to the cranking battery’s negative terminal is that if the contact causes a spark and ignites the gas, you are more than likely going to be over the top of the battery at the time and could easily end up with a face full of acid ( electrolyte ).


By making the last connection somewhere other than at the battery, while it far less likely to ignite gasses at the battery, if it does cause the battery to explode, you are in a much safer position.


Now find a suitable earthing point in the crippled vehicle’s engine bay ( if the cranking battery is located there ). This earthing point should be a bolt on the motor or something of that nature.


Do not use any body parts as the earthing point, because they are usually not thick enough to carry the startup current load.


With all connection made, leave the vehicles connected with the donor vehicle’s motor running at a high idle, for at least 2 minutes.


Once some time has elapsed, try starting the crippled vehicles motor.


If it does not start straightaway, turn the crippled vehicle’s ignition switch off and remove the key and give the crippled battery more charging time.


If the motor starts, remove the negative lead from both vehicles first, then remove the positive lead.


DO NOT switch the crippled vehicle’s motor off to test the crippled vehicles battery. If you are in the middle of nowhere and your motor is now running, don’t tempt fate.

[Homestar]

OK folks, I’ll start a Digital Multi Meter ( DMM ) tutorial in the next week.


But first, make sure you have a DMM handy.


This is just a suggestion, if you need to buy one, there are some very cheap and useful DMMs but if you think you might get some use and want a little better than basic, Altronics have a DMM for $45 ( Q1134 ) and this one has a handy advantage over most.


Most DMMs have a maximum current limit of 10 amps, but this one can handle up to 20 amps and this is a more useful limit when measuring circuit currents around a vehicle.


Anyway, I will start putting something together and see how we go.

Just a thought but maybe include an explanation of voltage and current in this from a very basic viewpoint - one of my jobs at work is Generator Training for our staff and one of the things I see all the time is misconceptions of what current is. You get a lot of people thinking that a 10 amp power point produces 10 amps, etc and not understanding it's the load that dictates current flow. I also think this lack of understanding is why most people don't understand how batteries charge and think a 100 amp alternator will put 100 amps into their battery. Things like that...

And on batteries - that would be a good chapter - explaining them in more detail, diffrent types, common misconceptions around use, abuse and charging from various devices.

[DiscoMick]

Thanks.
Is it true if both vehicles are connected while both engines are stopped, and then the donor vehicle is started, starting it can send a high current surge into the flat battery damaging it?
Just something I've heard said, but never tested.

[alien]

Or more importantly why a company(such as Toyota!! on their '04 Rav models) don't use a relay to power the headlights!

The switch is one of those turn-ey type indicator stalks, and the contacts inside eventually burn out, which results in the extra expense of having to purchase an indicator stalk when one really only wants a headlight switch .. which should have been a relay anyhow!

May have to wire up a couple of relays into the lighting system to prevent future occurrence.
Yet again Land Rover leading the way, every Defender is wired this way.

[Homestar]

Thanks.
Is it true if both vehicles are connected while both engines are stopped, and then the donor vehicle is started, starting it can send a high current surge into the flat battery damaging it?
Just something I've heard said, but never tested.

Assuming you mean when jump starting?

Answer is no. When the donor car is connected current will be flowing to the flatter battery to start with, when the donor vehicle is started, the alternator will also assist and supply what it can to the flatter battery - the current flow is dictated by the flat battery and how large the jumper cables are. The flat battery will draw as much current as it can - or what it is limited to by the cables and the other system. I'm my experience, the flat battery will only pull a 100 amps or so for a short time, then as it starts to take a charge, the current drops as the charge increases.

This is just the thing I was talking about in my last post - people not understanding current flow and why and when it does what. The donor vehicle can't send a surge of power - the current required is dictated by the flat battery and the limitations of the leads and system (battery and alternator) of the donor vehicle.

just scare tactics. There's certainly a right and wrong way to jump start a vehicle but killing the flat battery like this is BS - remember the flat battery could be U/S anyway depending on how and why it went flat so maybe that's where the myth comes from.

[drivesafe]

Thanks.
Is it true if both vehicles are connected while both engines are stopped, and then the donor vehicle is started, starting it can send a high current surge into the flat battery damaging it?
Just something I've heard said, but never tested.

Hi Mick and no a high “CURRENT” spike will not harm anything, including batteries, flat or otherwise, and high current "surges" occurs in all vehicle during normal use.


I think what you might be relating to is something Homestar raised.


Could you get a high “VOLTAGE” spike in that sort of situation.


First off the likelihood of voltage spikes being generated is always a possibility, and not just when jump starting. There are a large number of devices in vehicles that generate voltage spikes hundreds if not thousands of times, every time you drive a vehicle, but all vehicles have a massive voltage spike suppressor.


It’s called your cranking battery.


Even a stuffed cranking battery is still a very effective voltage spike suppressor.


While cranking batteries suppress major spikes, all automotive vehicle electronic devices come with their own builtin spike suppression and it is almost impossible to damage any vehicle’s electronics with high voltage spikes.


There are two exceptions, the first is when someone uses an electric welder on a vehicle with out setting the vehicle up properly.


The other, is if you attempt to replace a stuffed battery with a good one while the motor is running.


I have come across this situation twice, where someone had a stuffed cranking battery, got a jump start and then drove to a mates place, where he had a battery sitting around doing nothing.


When they got to the mates place, they were not sure if the replacement was any good, and to save having to possibly jump start the vehicle again, they simply left the motor running while they disconnected the stuffed cranking battery and by the time they had the replacement fitted, they had fried some of the vehicles electronics.


With no cranking battery to suppress the output of an alternate, an alternator can produce voltage spikes of 60+v and vehicle electronics are just not designed to tolerate such high spikes.

[Don 130]

Tim could we add correct procedure when welding on a vehicle. I Always disconnect the battery, but am often told by 'experts' (self proclaimed), that there's no need to.
Don.

[weeds]

Tim could we add correct procedure when welding on a vehicle. I Always disconnect the battery, but am often told by 'experts' (self proclaimed), that there's no need to.
Don.

Yes disconnecting is the best option without a doubt.....

Although for exhaust work I have never disconnected the earth is place right next to where you are welding , ever seen an exhaust place disconnect a battery.

[pop058]

Yes disconnecting is the best option without a doubt.....

Although for exhaust work I have never disconnected the earth is place right next to where you are welding , ever seen an exhaust place disconnect a battery.

Had some exhaust work done awhile ago (300TDi D1) and they put a "suppressor" across the battery.

[donh54]

Had some exhaust work done awhile ago (300TDi D1) and they put a "suppressor" across the battery.

Our local exhaust guy did the same. He told me that it isn't really necessary if the welder earth lead is close to the spot you're welding, and the welding current doesn't pass through anything other than the exhaust. He does it more for customer peace of mind - the customers in his shop can see the work area from the waiting room, and he has a lot of questions about that very subject.

[drivesafe]

Tim could we add correct procedure when welding on a vehicle.
Hi Don, and as I could not weld to save my life, I will leave this question to others, with experience with welding, to answer.

[Don 130]

Hi Don, and as I could not weld to save my life, I will leave this question to others, with experience with welding, to answer.

It's not the welding ability Tim, it's the stray current and what it can do to various electrical and electronic components.
Don.

[drivesafe]

It's not the welding ability Tim, it's the stray VOLTAGE and what it can do to various electrical and electronic components.
Don.
I think this is what you meant?

[drivesafe]

Hi folks and sorry for the delay with the DMM tutorial, but I’m flat out.


I have just ordered a small number of the DMMs mentioned earlier in this thread. The retail price is $45 and I can supply anyone wanting one of these for $48, including postage to anywhere in Australia.


I will be using one of these as the training device.

[Don 130]

I recently bought this one. Ok for the tutorial?

Cat III Multimeter with Temperature | Jaycar Electronics (https://www.jaycar.com.au/cat-iii-multimeter-with-temperature/p/QM1323)

Don.

[drivesafe]

I recently bought this one. Ok for the tutorial?

Cat III Multimeter with Temperature | Jaycar Electronics (https://www.jaycar.com.au/cat-iii-multimeter-with-temperature/p/QM1323)

Don.
Hi Don, that DMM will be fine and any DMM can be used.


When I get the time to start the tutorial, if you are unsure about the setting being selected, you can post up a photo of your particular DMM and the settings for your device will be posted up.


Sorry for the delay but I am flat-out but as soon as I have the time, I will start posting up the basics of using DMM.

[pop058]

No hurry Tim, we appreciate your efforts :thumbsup:

[rathgar]

Hi Ranga, here is some basic info about different types of automotive relays.


This is info I already have available, but if there is more you would like to know about them, just ask.


https://www.aulro.com/afvb/images/imported/2017/04/1030.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1031.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1032.jpg


https://www.aulro.com/afvb/images/imported/2017/04/1033.jpg

Am I missing something? A horn connected using the first diagram would be annoying. Should terminal 85 be to battery positive via a switch?

[pop058]

Maybe the earth terminal (86) is being earthed by the horn button ?

[Homestar]

Yes, earthed through the horn button, the description is a just a bit off.

[rathgar]

If someone is going to throw stones at other documents on the internet then they need to make sure their glasshouse is made from toughened safety glass.

[Homestar]

If someone is going to throw stones at other documents on the internet then they need to make sure their glasshouse is made from toughened safety glass.

It's not hard to figure out what he meant, and it's not hard to have some manners when asking for clarification either for that matter....

And Tim's place is made from from bullet proof glass as well I believe... ;)

[rathgar]

I'm not after clarification. Just pointing out that the internet is full of misinformation and no matter what the source is or how much of an expert he may appear to be is people should check the facts. One more document isn't going to change that.

My query was wrong anyhow as it was rightly said a horn would normally have a switched earth.

However the diagram also excludes a reference for a "fused" power supply to 85. How far do you want to take it?

[Mick_Marsh]

However the diagram also excludes a reference for a "fused" power supply to 85. How far do you want to take it?
Yes, misinformation is all over the internet, and here, apparently.
The fuse is used to protect the cable, not the device.
If I was designing the circuit, I would not fuse the relay coil. It takes such a low current I suspect the coil will blow before the wire's insulation burns. (Have you seen how thin the copper wire in a relay coil is? Much thinner than 0.5A fuse wire.) Besides, the horn is an emergency device. Emergency devices usually are a very simple circuit with minimal protection.
And why is the horn fused? When it fails, it is likely to draw a high current which may cause the cable to overheat and catch fire. Also a good reason to install a horn relay in modern cars with minimal copper used in the cables.

[rathgar]

Gee and I just tried to point out that the wiring diagram as presented would have the horn sounding continuously. Small correction required.

[Mick_Marsh]

Gee and I just tried to point out that the wiring diagram as presented would have the horn sounding continuously. Small correction required.
Thankyou for that.

[rathgar]

Really happy now I've made your day Mick!!

[cuppabillytea]

This is a great idea. Thanks a million.

Hears one out of the blue for you: Given that there is so much unlike metal contact in Land Rovers and the inclination for their owners to immerse them in water, both fresh and salt, do you think that it would be A, viable and B, feasible to marinize the electrics.? i.e. make the system above ground earth.

[Homestar]

This is a great idea. Thanks a million.

Hears one out of the blue for you: Given that there is so much unlike metal contact in Land Rovers and the inclination for their owners to immerse them in water, both fresh and salt, do you think that it would be A, viable and B, feasible to marinize the electrics.? i.e. make the system above ground earth.

Depends on your Land Rover Billy. I don't think it would be viable to do it, but potentially doable in some older vehicles with a bit of work. Starter, alternator and distributor would be the hardest parts I think.

What sort of long term gains you'd get I don't know. Unless the contact areas stay continually damp I wouldn't have thought you'd have the same issues long term as a Ship would suffer.

Easiest way is to not take it in the drink - leave it in the car park - you've got a Tugboat for playing in the wet stuff. :)

[bee utey]

Hears one out of the blue for you: Given that there is so much unlike metal contact in Land Rovers and the inclination for their owners to immerse them in water, both fresh and salt, do you think that it would be A, viable and B, feasible to marinize the electrics.? i.e. make the system above ground earth.

Most of the corrosion on a land Rover occurs due to small local corrosion cells wherever water can linger for hours after a dunking. Put a splot of mud on a clean steel or ally surface and keep it in the damp and shade and see what happens. Stray currents from operation will be the smallest contributors to corrosion, with the possible exception of aluminium alloy radiators. I once had an old rust bucket where the door lamp switch was screwed to a tiny patch of sound metal surrounded by a much larger patch of rusted metal. I don't know if this effect was due to stray current or the plating on the switch but the effect was strictly local.

On a Land Rover, the best defence against corrosion between a steel and ally component is to thoroughy seal the join against water ingress or just make sure it dries out very quickly after dunking. Steel engine mounts on a cast ally block don't tend to rust out because the heat of the engine dries the joint out quite quickly.

[cuppabillytea]

Depends on your Land Rover Billy. I don't think it would be viable to do it, but potentially doable in some older vehicles with a bit of work. Starter, alternator and distributor would be the hardest parts I think.

What sort of long term gains you'd get I don't know. Unless the contact areas stay continually damp I wouldn't have thought you'd have the same issues long term as a Ship would suffer.

Easiest way is to not take it in the drink - leave it in the car park - you've got a Tugboat for playing in the wet stuff. :)

Yes. Most marine systems are 48 V so you'd have to do every single component yourself. This would make it ridiculously complicated.


Most of the corrosion on a land Rover occurs due to small local corrosion cells wherever water can linger for hours after a dunking. Put a splot of mud on a clean steel or ally surface and keep it in the damp and shade and see what happens. Stray currents from operation will be the smallest contributors to corrosion, with the possible exception of aluminium alloy radiators. I once had an old rust bucket where the door lamp switch was screwed to a tiny patch of sound metal surrounded by a much larger patch of rusted metal. I don't know if this effect was due to stray current or the plating on the switch but the effect was strictly local.

On a Land Rover, the best defence against corrosion between a steel and ally component is to thoroughy seal the join against water ingress or just make sure it dries out very quickly after dunking. Steel engine mounts on a cast ally block don't tend to rust out because the heat of the engine dries the joint out quite quickly.

I tend to agree with you here. There are differences in potential across tiny areas in all metals, enough to let even a small droplet of water create an electrolytic corrosion cell.

[drivesafe]

Hi folks and my apologies for taking so long to get something going in the thread but I’m working 7 days a week, trying to keep order delivery times down.


But in the last month or so, I have had a number of situations brought to my attention, where people have either purchased an “expert designed” dual battery kit or had a dual battery system installed by a “professional”, and have end up with a death trap.


While most of the gear I supply Land Rover owners, is in kit form, and therefore is designed to be a safe as possible, but since the introduction of the latest versions of my isolators, I am supplying a lot more isolators to people with other makes of vehicles, and quite a few of these people already have had systems fitted and either want to upgrade their isolator or are planning on fitting their own set up because I do not have a vehicle specific kit for them.


What is happening, when people are purchasing one of my isolators, to make sure they are getting the best isolator for what they want to achieve, I will often ask them about their current or intended setup. This is where I am hearing about the down and outright death traps being supplied or fitted by self proclaimed “experts”.


The problem comes from people, who have no idea what they are selling, but they are giving “professional” advice about how a dual battery setup should be equipped. Again, this is info from people who have no genuine auto electrical knowledge, particularly when it comes to auto electrical SAFETY requirements.


Almost every component used in any dual battery setup has operational characteristics that most people are unaware of, especially safety perimeters that MUST be factored in when designing a dual battery setup.


The most common error, and the most dangerous one, is the use of totally inappropriate sized fuses and circuit breakers.


Here is an example.


There is an individual who has a book out on requirements for setting up for RV use, which covers all manor of RV subjects, including electrical “advice”. In the advertising used to promote his book, he displays a diagram of a basic dual battery wiring setup.


In his diagram he uses 6B&S cable to run from the tow vehicle to the house battery in the caravan and this is a good choice.


He recommends the use of 50 amp Anderson Power Connectors to connect the cable between the tow vehicle and the caravan, and again, a good choice.


He shows fuses being used near the batteries at each end of the cable, which is the correct safety requirement for this type of auto electrical setup.


Then it all goes pear shaped because he recommends using 100 amp fuses at each end of the cable.


While there is a lot more to it, which I will cover in more detail in a later post, but surely commonsense ( not auto electrical knowledge ) would dictate that if you are using a 50 amp rated Anderson plug, then the maximum current rate of the circuit protection device for the same circuit should be no more than 50 amps, not 100 amps.


6B&S cabling is rated at a maximum continuos current of 105 amps BUT, this is in open air, which the cabling is not, when run through a vehicle.


A number of cable manufacturers have DERATING tables on their websites, making it pretty easy to work out safe maximum current capacities of deferent cable sizes, including 6B&S. The maximum safe continuos current for 6B&S should be based at around 80 amps.


While 50 amp Anderson plugs are called just that, 50 amp, but in the right circumstances, a 50 amp Anderson plus can safely carry a continuos current load of 95 amps. More on this later.


Here is where the real danger lays. Few people working in this industry have never bothered to look up the operating specs for the standard automotive fuses or circuit breakers, and this has lead to grossly higher current rated fuses and circuit breakers ( CB ) being commonly used where they should not be used.


First off, the current marked on an automotive fuse or CB is what that fuse or CB is designed to carry for at least 4 hours. But to be able to carry it’s marked rate for 4 hours, it needs to carry higher currents for shorter times.


On average, automotive fuses and CBs will carry 125% to 135% of their marked rate for around 30 minutes and much higher currents for shorter periods.


This means that the 6B&S cable in the diagram could carry 135 amps for 30 minutes without causing the fuse to go open circuit ( to blow ), which means, for 30 minutes, the cable could be carrying around a 75% high current than the cable can safely handle.


Now to the specs for a 50 amp Anderson plug. The maximum continuos safe current for a 50 amp Anderson plug is 95 amps, but this is at 25C, but with 6B&S cable connected to the Anderson plug and with the cable carrying it’s maximum safe current limit of 80 amps, the cable will be quite WARM at that current rate and will cause the Anderson plug to run at a higher temperature.


The cabling and plug are going to be closer to 50C, which brings the Anderson plug’s safe maximum current rate down to around 75 amps.


So with the maximum safe current for the 50 amp Anderson plug being around 75 amps and the 100 amp fuse not likely to go open circuit with currents under 135 amps, you risk having currents nearly double the safe maximum being carried through the Anderson plug for around 30 minutes.


NOTE, until recently, a well known Australian supplier of dual battery gear also recommended 100 amp fuses in similar setups????


When setting up a dual battery system using 6B&S cabling, the maximum current rating for in-line fuse or circuit breaker protection is 60 amps, not 100 amps. To improve the safety of my dual battery systems, I prefer 50 amp Auto Resetting Circuit Breakers, but I will cover this in a later post.


While I would not classify the misinformation in the diagram as amounting to being a death trap, it is exceedingly dangerous. In my next post I will show how companies, who are nothing more than Box Sellers, are putting people’s lives at risk by selling much more dangerous setups.

[LuckyLes]

Hi Tim,
This is a great thread and I am reading it with much interest. As a retired auto workshop owner I used to see this stuff all of the time and would shake my head in disbelief at times.
Many thanks for sharing your knowledge.
Les:BigThumb::BigThumb:

[DiscoMick]

Thanks for that. It's very helpful to an amateur like me.
Looks like my auto electrician did the right thing by fitting 60 amp fuses.

[drivesafe]

Once again, this post is about warning people about how dangerous Dual Battery Systems ( DBS ) can be, if people deal with “self-proclaimed experts” who really have no idea what they are selling.


Now this is not about trying to get people to buy from my business rather that buy from some other DBS supplier. I have not supplied separate bits a pieces for DBS setups for quite a few years now. The primary reason for this post is to give people a heads up on what is safe when looking for DBS components, when people are setting up their own systems.


Some time back I was on a Pajero forum where one of the members had just watched a video on a supplier’s website that was promoted as being the “correct” way to carry out a DBS setup. The member stated that this was a great video for anyone wanting to learn how to fit a DBS. The problem is that anyone how follows the “advice” given in this video could quite simple end up burning their vehicle to the ground.


First off, they recommend using 8B&S ( 7.9mm2 ) cable for a DBS setup, and while 8B&S will work, it will take at least 50% more driving time to recharge a battery over the drive time required when using 6B&S (13.5mm2 ) cable.


They then fit an in-line fuse near the cranking battery and they recommend using an 80 amp fuse to protect the 8B&S cabling. The MAXIMUM current rating for any fuse or CB intended to protect 8B&S in a DBS is just 40 amps. While I have already covered how much of a danger this poses, but this is not the worst of it.


Then they show how to install and wire up an auxiliary battery in the rear cargo area of a vehicle. They install the battery and then wire it up to the cabling coming from the front of the of the vehicle. The cabling is simply connected to the auxiliary with no in-line protection. No fuse or CB.


This is utter lunacy, and could easily lead to a vehicle being being burnt to the ground if a short occurs any where in the cabling.


To demonstrate just how little they know about this field, later in the video, they recommend fitting a 20 amp DC/DC device, which if they had fitted the appropriate size cabling in the first place, would have been a waste of time.


But they then actually make it a total waste of time and money by stating that you now run cabling from the rear mounted auxiliary battery to a battery in a caravan, and the DC/DC device will charge both batteries.


Had they bothered to read the DC/DC manufacturer’s installation instruction, no matter what brand the DC/DC device is, all DC/DC manufacturers specifically state that the DC/DC device MUST BE fitted as close as possible to the battery being charged by that device.


With their setup, the auxiliary battery will take many, MANY hours of driving to fully charge it, if it is in a low state, and because of the thin cable combined with how far away the DC/DC device is located from the caravan battery, the caravan battery will NEVER be fully charged, regardless of how much driving you might do.


The problem with the “expert” advice given in this and the previous DBS setup, the “experts” based the use of the over current rated safety devices on them being able to go open circuit in the advent of a short circuit occurring and yes, in this type of event, they both would go open circuit ( actually in the second example, only the cranking battery would be protected from a short circuit event ).


But if either of these “self-proclaimed experts” had any real knowledge of how DBSs work, they would know that the greatest potential danger for a DBS comes from current overload, not short circuits. And the reason for this is because there a cranking battery and alternator at one end of the cabling and an auxiliary battery at the other end of the cabling.


This setup means there is a high current supply potential at both ends of the setup but the greatest danger comes from the auxiliary battery.


The danger arises if the auxiliary battery drops a cell and shorts internally. This will not cause a dead short but it can cause a very high current draw.


This current draw is basically going to be the same, regardless of the thickness of the cable, but the thicker the cable, the longer the cable takes to heat up.


In the first post, where 6B&S cabling and a 100 amp is used, the fuse may or may not go open circuit before cable’s insulation ignites, but in this second setup, where they have used an 80 fuse to protect 8B&S cabling, because of the thinner cabling, the cabling will heat more quickly and has a much greater potential of the insulation igniting before the fuse ever blows.


The setup they are promoting is an out and out death trap and their advice amounts to instructing unsuspecting people on how to fit a suicide kit to their vehicles.

[drivesafe]

OK folks, this thread is about an area of Dual Battery Systems ( DBS ) where fires do occur when “experts” have carried out the installation of substandard wiring and protection.


It is commonplace to find the power cabling use to charge the house battery in many caravans and camper trailers is way to thin. Many RV manufacturers use 8B&S ( 7.9mm2 ) cabling and some even use 6mm AUTO ( 4.5mm2 ) WIRING to charge the house battery in their caravans or camper trailers.


Many RV manufacturers elect to use this thinner cabling because it fits into the terminals of 7 and 12 pin trailer plugs ( more on this later ).


While the obvious problem is that the house battery is just not going to charge properly, if at all, with this size cabling, but there is a major risk of fires occurring and they do occur, because these same manufacturers will often use the wrong size fuse or Circuit Breaker ( CB ) to protect this under sized cabling.


It is just as commonplace to find these same manufacturers have use a 50 amp CB to protect 6mm AUTO cabling, and as already covered in the two previous posts, but in this type of set, particularly in caravans, regularly results if fires occurring because a battery has failed or there has been a bank of batteries fit, and the first time theses batteries are in a low state and are being charge while driving, the large current load simply overwhelms the thin wiring and causes it’s insulation to over heat and ignite.


This type of situation is not just limited to caravan or camper trailer wiring.


You may have your Land Rover set up with a DBS and decide to buy a caravan or camper trailer. If your Land Rover has already been wired up with an Anderson plug at the rear, based on info supplied on this form, then you are probably set up properly and safely.


But what regularly occurs is if you are not fully wired up to provide power to your new caravan or camper trailer, you may take the “advice” from the caravan supplier and go to their auto electrician to get your Land Rover wired up for electric brakes and additional wiring for powering your new caravan.


This is exactly what happened to two of my customers.


The auto electricians in both cases, ran 6mm AUTO ( 4.5mm2 ) cable ( read wire ) from the auxiliary battery to the rear of their D4s, not just for the electric brakes, but also for power to the caravan, which means for charging the house batteries in the caravan.


In both cases, the auto electricians had fitted 50 amp auto resetting circuit breaker to “protect” the 6mm AUTO cable.


Both vehicles ended up with fires occurring in the engine bay.


Armed with the info supplied in these three posts, you should be able to protect your vehicles, and yourselves, from potentially dangerous Dual Battery Systems.


I will cover the use of Anderson plugs verses trailer plugs in the next post.

[DiscoMick]

So what size wire would you recommend? You've got me worried now.

[drivesafe]

Hi Mike and sorry mate I missed your post.

What is the intended use of the wire/cable you want to know about?

Is it for a dual battery setup or for other use?

[drivesafe]

There are two types of Anderson plugs, genuine Anderson plugs, and copies.


Genuine Anderson plugs are branded with either ANDERSON POWER CONNECTORS or SMH ( which stands for Southern Machinery Holding, the original parent company of Anderson Power Connectors ).


Any other branding indicates a non genuine copy, and while this may not seem important, there is a huge difference between the genuine and copies, both in current handling capabilities and safety.


First and foremost, the size of the terminals can vary greatly between the genuine and copies. It would surprise most people if they saw how much narrower non genuine terminals are when placed beside the real McCoy terminals.


It is not unusual to see as much as a third difference in width size between the genuine Anderson terminals and copies. This means at least a third less contact area and that means a much lower current carrying capacity when using copies.


Genuine Anderson plugs can carry as much 95 amps with safety, but most copy plugs are lucky to be able to carry their so called 50 amp rating. This is often demonstrated when you come across a melted Anderson plug and they are never genuine Anderson plugs.


It pays to be careful when buying Anderson plugs because it is now commonplace to see ads where they state “Anderson like plugs” or similar claims and note, there are some very well know auto electrical brands with their own copies and they are no where near as good as the genuine Anderson plugs.


Now to substituting trailer plugs for high current applications, instead of using Anderson plugs.


First major difference between genuine Anderson plug terminals and trailer plug terminals is that genuine Anderson plug terminals are specifically designed for what the industry calls “hot make and break” connections. This means they can be connected and disconnected while high currents are applied to the circuit.


Anderson plugs can carry out 250 “hot make and break” connections at 50 amps.


While the large terminals on a 12 pin trailer plug can carry 35 amps, they should never have a “hot make and break” connection. Doing so can causes arcing to occur and while Anderson plugs can tolerate this, trailer plugs can not and continually doing so with trailer plugs can very quickly damage their terminals. This can, over time, dramatically reduce the current carrying capacity of trailer plugs.


Another problem with trying to use trailer plugs for carrying high current loads, is the fact that their terminals are easily tarnished and tarnished terminals can cause both a reduction in current carrying capacity but tarnished terminals can also create resistance in the contact area, which can result in high temperatures being generated in the trailer plug.

NOTE, trailer plugs are not designed to tolerate heat.


Also a problem with trailer plugs is the more you plug and unplug them the weaker the contact pressure between the male and female terminal becomes, again, causing a reduction it the current carrying capacity.


With genuine Anderson terminals, both the above problems are pretty well eliminated because Anderson plug terminals are spring loaded so that they self-clean every time you plug and unplug, plus they maintain a constant contact pressure over the lifespan of the Anderson plug.


So it pays to use the right connector for the desired requirement and Anderson plugs are now the industry’s preferred connector for dual battery connections between the tow vehicle and caravans and camper trailers.


BTW, next time you have been camping, and you have used a fair bit of your house battery capacity, when you get back on the road, after you have been driving for just 15 to 20 minutes, try pulling over and going back to your Anderson plugs.


You may be very surprised to feel just how warm they can get. NOTE, they should not be that hot that you can not handle them, but they can be quite hot. If they are that hot that you can not handle them, you have a problem that needs to be addressed.

[Eevo]

can we get a quick article why slow charging a battery is batter than fast charging?

[Don 130]

I recently got genuine Anderson plugs from this mob (http://stores.ebay.com.au/autoelecau/_i.html?_nkw=anderson+plugs&submit=Search&_sid=1026544065)on ebay.
I thought the value and service pretty good.
Don.

[drivesafe]

can we get a quick article why slow charging a battery is batter than fast charging?
Hi Eevo, before going into charging details I think it might be useful to explain what SoC means.


SoC, stands for State of Charge, but there is also the reverse abbreviation and this is DoD. DoD stands for depth of discharge.


SoC indicates the amount of usable battery capacity reminding in a given battery, whereas DoD indicates the amount of battery capacity already discharge from that same battery.


For simplicity, I will only use SoC in my articles as a means of giving measurements relating to battery capacity. I will post up a charter a little further down, showing what the SoC measurement stands for in a battery but there's a lot more to it than just straight out voltage equals existing capacity.


Ah or ampere hours marked on a battery, roughly indicate the amount of hours you can draw a one amp load from a battery.


In theory, if you have a 100Ah battery and you apply a one amp load to that battery, say a 12W globe ( which will have roughly a 1 amp draw ), then that globe should glow for 100 hours.


In reality, the amount of usable ampere hours is controlled by a number of factors. Factors like the age of the battery, how well the battery has been maintained and so on.


Now to confuse the issue.


The SoC measurement of a battery is an indication of the State of Charge of the battery’s capacity that can be charged, and I will try to explain.


As above, age and condition of a battery will have a bearing on the actual amount of a battery’s original capacity that is still usable. When you measure the voltage to determine the SoC of the battery, you will only be measuring the SoC of this usable capacity.


For example, if you have a 100Ah battery that is partially sulphated ( I will cover the sulphation in more detail in the next article ) and you actually only have say 80Ah of usable capacity. If the battery is fully charged, and you get a 12.7v voltage reading, which indicates an SoC of 100%, in this case it does not mean you have 100% of the original 100Ah fully charged, you only have 100% of the 80Ah now available that is full charged.


The problem is that from the SoC measurement, you have no idea that you only have 80Ah available, and in this case, your 12w globe will only run for 80 hours.


You will need something that is capable of measuring current in and out as well as the voltage, and be able to analyse this data, to be able to get an accurate capacity indication. I am not going to cover that here.


So a simple voltage reading is not a reliable indication of the true available capacity of a battery, but in most RV applications, it will give you the info you need.


SPECIAL NOTE. There are two different types of voltage measurement used to determine the SoC of a battery. This article is based on using the voltage measured from a battery that is in use. There is also OPEN CIRCUIT VOLTAGE READINGS, where the battery must site in a No-Charger/No-Load state for at least 24 hours, before the voltage reading is taken.


OPEN CIRCUIT VOLTAGE READINGS are far more prone to erroneous results and are pretty useless while on holidays, when you need to have the battery sit around used for 24 hours, just to see how available capacity there is.


The chart below is comparatively accurate when measuring any form of lead acid battery. OPEN CIRCUIT VOLTAGE READINGS are battery specific, which means you have to have the correct OPEN CIRCUIT VOLTAGE Chart for the specific make and type of battery you are trying to monitor.

130643

[VladTepes]

Great idea.

Might save some reinventing the wheel...

Auto Electrics - How to Use a Multimeter (https://www.aulro.com/afvb/the-good-oil/210372-auto-electrics-how-use-multimeter.html)

Auto Electrics De-Mystified (https://www.aulro.com/afvb/the-good-oil/210371-auto-electrics-de-mystified.html)

Soldering (http://gsx1400owners.org/forum/index.php'topic=480.0)

[drivesafe]

Hi folks and my sincere apologies for taking so long to post up info in this thread. I am just flat-out and no time has been available.


Owing to the amount of time I am now spending on the phone each and every day, fault finding and fixing dual battery electrical problems, I would be far better off posting up info and instructions in this thread, so people might be able to sort out problems for themselves, before they need to phone me.


NOTE, I am still going to be available to phone but hope this thread will still reduce the need to call me.


To give you an idea of what I have to address. Over the weekend, I received a number of call from a gent with a D4, who was having serious charging problems with his setup.


He and a mate with a Toyota Land Cruiser both have the same new caravan.


They are both having problems charging their auxiliary and house batteries, even after a 5 hour drive.


I go the D4 owner to take some voltage measurements with the motor idling.


He tells me he was getting 14.4 at the cranking battery and 14.4v at the rear plug ( not an anderson plug ).


I ask “was this with the caravan connected?” and “NO” was the reply.


So the caravan was connected and the voltage now drops to 12.7v at the trailer connector.


After some investigating, it turns out that his D4 dual battery WIRING was 6mm AUTO or 4.5mm2 twin, it should have been 6B&S or 13.5mm2.


The caravan wiring was even better as it was 4mm AUTO or 2.5mm2, again it should have been 6B&S or 13.5mm2.


The most annoying part of this conversation was that both he and his mate had gone to the same auto electrician, who had “professionally” installed both systems, but not with one of my isolators. He had fitted Redarc VSRs.


The gent had rang me because he could not get help anywhere else and he and his mate were in the middle of nowhere, in WA.


On Monday, I get a call from a gent with an Amarok, who had bought one of my Amarok DBS kits, but because he was short of time before his trip, had had the kit “professionally” installed by a well known 4x4 outlet.


In his case, which is still being sorted, even after a long drive, his SC80 would shutdown after bing parked for just a few hours.


The voltage at the cranking battery was around 12v after the shutdown, the auxiliary battery was at 12.7v and there was no power at the Anderson plug once the SC80 had shut down. ????????????????


Even with the SC80 shut down, with 12.7v at the auxiliary battery, there should have been 12.7v at the Anderson plug.


The clowns ( professionals ) at the 4x4 outlet were supplied with a Ready-To-Fit complete kit but for some unknown reason, they have modified/altered the cabling?


So can I suggest that people with DBS problems, with mine systems or some other brand, please post up your problems here and then everybody can see what to avoid and how to fix these problems.

[Homestar]

Geez you're more patient than I am. If it wasn't your system they had fitted or modified one of yours I hope you billed them appropriately for your time.

[drivesafe]

Hi folks and the most common enquiry I get is about problems relating to low cranking batteries and the error message “Low battery start engine” or the likes.


In the vast majority of these situations, the owner is the problem, not the batteries, not the vehicle and not my dual battery system.


I would guess 95% of the time, it is the use of the vehicle ( or lack of use ) that is the root course of this problem.


Regardless of you doing a LONG trip every month or so, short driving, as I have labelled it before, Shopping Trolley Syndrome, I have found is the prime cause of the early demise of cranking batteries, and many auxiliary batteries as well.


First to what occurs in the cranking battery in Shopping Trolley Syndrome situations.


When you first buy your new vehicle, it comes with a battery capable of supplying 100% of it’s designed capacity. NOTE this also applies when you change an old battery for a new one.


But as a Cranking battery, it rarely needs to supply more than a few percent of it’s capacity to start the motor.


You then do lots of short trips, and initially, you manage to replace “MOST” of the energy used each time you start your motor. But you never quite replace the total energy used when you started your motor.


Now the following is a very simplistic explanation of what occurs inside the battery.


Because you do not drive long enough to FULLY recharge the battery, a very, VERY small portion of the battery’s plate surface gets a scale building up, where the sulphuric acid solidifies ( sulphates ) on a minute area of the battery plate surface.


The area covered is now pretty well unusable ( or can not be charged ).


This sulfration can take years to build up to a point where it has any effect on the battery’s ability to start your motor. But over time, as more battery plate surface area becomes effected by the build up of sulfation, the performance of the battery, when starting a motor, will become sluggish.


At this point, the battery is probably still recoverable, but at this point, the amount of battery plate surface area being effected rapidly increases.


This rapid increase is caused by the fact that, while you still need the same amount of energy ( battery capacity ) to start the motor but as more area becomes unusable, you actually need to drive longer to allow the battery capacity used to start the motor, to be replaced.


Because you are still driving the same short trips, the mount of battery capacity being replaced is rapidly getting less and less with each trip.


You get the picture, and even with the periodical long trip, as the usable amount of the battery’s capacity is greatly diminished, you are only able to fully charge the small portion of battery’s capacity that is still usable.


In the initial stages of the sulfration, your battery voltage can still show a fully charged state, but this is only an indication of the state of charge of the USABLE portion of the battery’s capacity.


As the sulfration progresses, because you are using far more of what remains of the battery capacity while starting your motor and you are replacing far less while driving, even this remaining portion will now not be able to be fully charged, causing the voltage to drop in the battery, and this is when you begin getting “Low battery start engine” messages.


Once you start getting this messages, you should do something immediately to correct the problem causing the message ( see below ).


If you do nothing about the problem, in a very short time, the battery capacity and voltage level will drop to a point where you have a “flat battery” and you can no longer start your motor.


In many cases, by this stage, a cranking battery in this condition, is going to be hard to recover, if not impossible to recover.


As stated above, the sulfration of a battery can take quite a long time and it will take quite a long time to reverse the effects of sulfration, but in most cases, partial or full recovery can be achieved, but again it will take some time.


To try to reverse the effects of Sulfration, you need a 3 stage ( or more stages ) battery charger. It must have at least a BULK, ABSORPTION and a FLOAT mode.


Speed in charging is NOT required, and a small charger is much better for your battery than a large charger. Any charger with a charge capacity up to about 10 amps for a single battery setup and up to 15 amps for two or more batteries will be fine.


A 5 to 7 amp charger will work well in the recovery of any battery. So don’t go buying a big charger, just to use for recovering and maintaining your batteries.


To try to recover a sulphated battery, connect your battery charger in the evening and let it run all night.


Many people will connect a battery charger and run it till it goes into FLOAT mode and then they remove the charger. While this will recharge the used capacity that can be charged, it does nothing for recovering lost capacity.


In the morning, disconnect the charger.


Repeat this process for as long as possible, and for badly sulphated batteries, it may take a week or two to get the battery back to a decent condition.


Also, with small battery chargers and a large battery or battery bank, your charger may stay in BULK and ABSORPTION mode for a few nights, but it will then fully charge the batteries eventually.


Each night, the amount of time a small charger is in BULK and ABSORPTION mode will get shorter and shorter then each night it will go into FLOAT mode by the next morning.


It is actually the length of time the charger is on that helps to S-L-O-W-L-Y reverse the effects of sulfration.


While the charger is on, regardless of which stage it is in, the chemical reaction the charger causes in the battery, very, VERY S-L-O-W-L-Y, dissolves the scale off the surface of the battery’s plates.


This progressively increases the battery’s capacity and in many cases, can bring a battery back to or near it’s original capacity.


This process should be carried out for a week or so, even when you are using the vehicle during the day.


If you are not driving the vehicle at all, still only charge overnight and turn the charger off during the day.


There are two reasons for this type of operation. First off, the effects of dissolving the scale reduce with the amount of time the charger is continually on, and after about 12 hours, there is little gained.


Plus by leaving the charger off for a period, like 12 hours, even if the vehicle is driven between charge cycles, the electrolyte in the battery will settle.


Regardless of the state of charge of a battery, most battery chargers, when first turned on, go straight to the BULK stage, and then analyse the battery’s actual state of charge.


The charger will then go to the appropriate charging mode required.


This initial BULK charge helps to stir up and mix the electrolyte properly, and correctly mixed electrolyte also helps to reduce the sulfration.


Once this initial recovery is carried out, it is recommended to do at least one overnight recovery charge cycle once or twice a month where vehicles are not used all the time and/or are continually used for short trips.


BTW, if you have an appropriate sized solar panel, this will do exactly the same thing, except it will automatically turn on in the morning ( sunup ) and and automatically turn off in the evening ( sundown ) and is idea for use on vehicles that are left unused for long periods of time.

[rar110]

Thanks Tim

I am guilty of shopping trolly charging. I was charging it overnight every 3-4 mths but this was not enough. The battery in the L322 failed recently prematurely.

I tried reviving it using a multi stage charger a few times without success. Voltage would quickly drop to below 11v.

After fitting a new battery I thought I would try drop fixing the old battery a few times to see if that removed the scale. Obviously, I wouldn’t drop it so hard to crack the case.

I then put it on the charger again and this time it took charge. After a month or so of sitting it’s still at 12.35v. Not bad but should put it on again.

Has the drop fix worked at removing the scale? Is it a possible last ditch option?

[Eevo]

Has the drop fix worked at removing the scale? Is it a possible last ditch option?

i'll get the fire extinguisher

[Blknight.aus]

Probably worthy of a book in itself but what about when a DC/DC charger is appropriate, and when it is not.

if your not stepping up or down 24/12 or 12/24 its not.

Weldings simple. drop the earth lead off and tie it away from the battery, that goes for all of your batteries, Isolator switches count and drop the earth point to your solar system as well.

in 90% of cases you dont actually need to do this as most people when welding clamp close to the weld, the current goes no where but between the tip and the welder earth. BUT.. what if... you're welding on the exhaust, the earth lead on the motor is shot, its earthing though the earth on the electronics and the handbrake cable (which is high resistance compared to the earth in the electronics so the grunt is taking its first path via the electronics) and because you've got a bit of an odd angle you accidentally short the shield of the mig to the chassis...

the current now goes down the chassis, into the body earth, into the electronics and handbrake cable up to the engine and back down the exhaust where you clamped it.

lets have a little fun and say you were positive earth welding because of the wire and welder you were using. What just happened to your electronigc?

[rar110]

i'll get the fire extinguisher

You always like drama. [emoji23]

[Eevo]

You always like drama. [emoji23]
experience has taught me alot

[drivesafe]

Regenerative braking is only found in ALL ELECTRIC vehicles and some electric hybrids.


To use the term “Regenerative braking” is a misnomer when covering the subject of Variable Voltage Alternator operations in conventional vehicles, because conventional vehicles do not have regenerative braking, it is simply variable voltage algorithms, controlled by the ECU/BMS which act according to whether the ACCELERATOR PEDAL is pressed or not pressed and has absolutely nothing to do with applying the brakes.


While it may sound trivial, it is actually quite an important difference. If the battery was only able to be charged while braking, the total amount of time spent charging the battery during each drive would be VERY short and you would have no chance of replacing the energy used while starting the motor.


The actual amount of recharging time is much greater thanks to this being carried out when ever you lift your foot on the accelerator peddle.


Furthermore, the alternator operation is based on a number of factors, but the primary charging of the cranking battery is achieved using the KINETIC energy of the vehicle, again you lift your foot on the accelerator peddle.


Also note, this type of “CONSTANTLY” Varying Voltage Alternator operation is primarily used in vehicles equipped with STOP/START function. There are exceptions, like some later model Land Rovers, both with and without STOP/START.


Anyone can test this at anytime. The next time you are driving up a hill and the voltage remains low. Then as you crest the hill and coast down the other side, as you lift your foot off the ACCELERATOR PEDAL, the voltage rises to what ever the BMS requires.


Turning on headlights or air conditioners can also have an effect on how low or high the alternator voltage is set at.


The one over-riding factor is the actual state of charge of the cranking battery.


If the BMS determines that the cranking battery is in a low state of charge, the BMS will ignore whether the accelerator peddle is pressed or not pressed, and will maintain a CONSTANT voltage till the BMS determines the cranking battery is in a high state of charger.


This CONSTANT voltage is usually around 14.6v - 14.7v

[VladTepes]

Revisiting this thread, wasn't this info supposed to end up on your website, or did that never happen?
Or is it something to do with your website being updated/changed?

[drivesafe]

Hi Vlad and my apologies to everyone waiting for this thread to advance further.

I am flat out trying to test some new products, develop new gear, keep up with orders and I want to make some short videos to go here and on my web site, and my website is in need of some serious updating.

There is just not enough hours in the day.

[drivesafe]

THE ADVANTAGES OUR TRAXIDE LAND ROVER KITS GIVE YOU OVER A DC/DC SETUPS

There are lots of claims that having a SMART ALTERNATOR means you need a DC/DC device to be able to properly recharge your auxiliary battery. With the Discovery 3 and 4 ( and many other new vehicles like Ford Rangers and VW Amaroks ), this is nothing more than deliberately misleading advertising hype.

This thread is about teaching people about basic vehicle electrics, so they can test and fix problems in their vehicles, or see that a specific electrical operation is normal and everything is fine with the way their vehicle’s electrics is performing.

This specific post is alone this line of educating people as to what is the best, or optimum way to set up a dual battery system in the Land Rover.
No other Land Rover Dual Battery System offers the many features or advantages like our systems provide and here is a comparison between our Discovery 3 and 4 Dual Battery Systems and DC/DC setup. And this is blatant advertising for my gear, but the REAL facts do need to be covered so people can make the best choice, when trying to sort through all the grossly exaggerated advertising hype surrounding DC/DC devices and their use.

PLEASE NOTE the following info is based on the feedback we have received from many of the more than 4,500 D3 and D4 owners using our kits both here in Australia and around the world.

Because of the way our isolators allow up to 50% of the cranking battery’s capacity to be used to help power your accessories, which adds an additional 45Ah to the auxiliary battery’s 55Ah. This gives you a total of 100Ah of battery capacity for running your accessories while camping.
With a DC/DC setup, because an Optima 55Ah Yellowtop battery is the largest that will fit under the bonnet of a D3 or D4, you only have a total of 55Ah available.

With a 20 or 25 amp DC/DC setup, if you use all the 55Ah capacity while camping, the auxiliary battery will be discharged down to 0% SoC ( 10.5v ) and you will now need need to drive for at least 3 hours to allow the DC/DC device enough time to be able to replace 95% of that used capacity. See the explanation relating to 95% State of Charge ( SoC ) below.

With one of our systems, if you use the same 55Ah capacity while camping, your cranking battery and auxiliary battery will only be discharged down to a bit over 60% SoC ( 12.2v ). Because of the large alternators in D3s and D4s, it will take less than an hours driving to have both batteries back over 95%.

This means our systems replace the same amount of used battery capacity, 3 to 4 times quicker than a DC/DC device can.

But even if you use the full 100Ah capacity that is available with one of our systems, you will charge the auxiliary battery back over 95% in about 45 minutes to less than an hour, and charge your cranking battery to over 95% in less than an hour and a half.

So in reality, our dual battery system paired up with your large alternator, will replace around double the used battery capacity in less than half the time that a DC/DC device will take to replace just half of that capacity.

And the advantages of fitting one of our systems doesn’t end there!

Because of the way our isolators keep the cranking and the auxiliary batteries connected together after the motor is turned off, and because the Optima Yellowtop battery is a rapid charging battery, there are a number of special advantages only available with our systems.

When driving around town, every time you turn off your motor, because the Optima charges quicker than any other battery, the Optima is always going to be in a higher state of charge than the cranking battery, and because the optima battery is always in a higher state of charge, it will now slowly back discharge into the cranking battery, keeping the cranking battery in a higher state of charge, and this helps to keep the cranking battery in a better condition and help extend the operating life of the cranking battery, while having no detrimental effect on the auxiliary battery.

Furthermore, again because our isolator keeps the batteries connected, when you go to start your motor, while the bulk of the energy needed to start your motor will still come from the cranking battery, but the auxiliary battery now assists the cranking battery every time you start your motor.

This makes it easier for the motor to start and also, because less energy is drawn from the cranking battery, while starting the motor, the cranking battery is recharged in a shorter drive time.

This one feature alone, of sharing the load while starting the motor, makes a huge difference in vehicles that are regularly driven for short distances around town, the “Shopping Trolley Syndrome".

None of these features are available when a DC/DC setup is used.

So the next time someone tries to tell you that a DC/DC device is the only way to charge your D3’s or D4’s auxiliary battery, you know they either haven’t got a clue how the alternator works in your D3 or D4, or they just want to sell you something you do not need.


CHARGING LEAD ACID BATTERIES TO A 100% STARE OF CHARGE ( SoC )

The following is basically what happens when charging Lead Acid type batteries to 95% SoC.

First off, the label "Lead Acid" battery is usually used for Wet Cell or Flooded type batteries. While this is correct, but AGM and Gel Batteries are also Lead Acid Batteries and when I state Lead Acid Batteries on this website, I am referring to all types of Lead Acid Batteries.

When charging a lead acid battery with a DC/DC device, or from Solar Panel Regulator or with a Battery Charger and from an Alternator, the charging current, while charging low to moderately discharge lead acid batteries, will be controlled by the charging device and this is known as the “BULK” stage of a charging cycle.

DC/DC devices, Solar Panel Regulators and Battery Chargers all have a LIMITED charge current while Bulk charging. This means these devices limit the charge current during the Bulk stage of the charge cycle.

These devises, because they have a set limited charge current, are known as Constant CURRENT Charging devices.

An Alternator, because most have a very high charge current capability, which is usually far greater than most batteries will be able to absorb, are known as a Constant VOLTAGE Charging device.

Optima Yellowtop batteries are a special type of battery that will safely accept “unlimited” charge current, according to their manufacturer. This means they can take everything available from the alternator.

All lead acid batteries will charge at the charge current being applied to them until the battery’s terminal voltage reaches the charging devices maximum charger VOLTAGE. From this point in the charge cycle, while the charge VOLTAGE remains at a constant maximum voltage level, the current will now taper off, and this is what is called the ABSORPTION stage.

The current being draw by the battery while in the ABSORPTION stage is controlled by the battery itself and no longer controlled by the charging device. The charge being ABSORBED by the battery now tapers off from what ever the maximum limited charge current of the devices is at the point where the charger goes from the BULK to ABSORPTION stage and the battery now continues to charge in the ABSORPTION stage.

If the charging device is allowed long enough time, the battery will eventually reach a 100% SoC. At which point the charging device transitions to the FLOAT Stage of the charging cycle.

When charging with a DC/DC device, or from Solar Panel Regulator or with a Battery Charger, the transition from the BULK stage to the next stage in the charging cycle, the ABSORPTION stage, occurs when the battery is at about an 80% SoC. Now a number of factors have to be taken into account before the exact transition point occurs but working on about at “roughly" 80% SoC is accurate enough for what is being covered here.

While the charging current progressively reduces once the charge cycle is in the ABSORPTION stage, using a 20 amp DC/DC device, to charge a battery from a starting SoC of 0% ( 10.5V ) your 55Ah Yellowtop battery will reach 95% SoC after about 3 or more hours of driving.
The last 5% of the charge will now take at least another 3 hours of driving.

With the alternator directly charging the auxiliary battery ( via one of our isolators ), your 55Ah Yellowtop will go into ABSORPTION stage very quickly. In this case, because of the high charge voltage and high charge current, the Yellowtop will be at as low as 30% SoC but the battery will still be drawing 70 or 80 amps at the beginning of the ABSORPTION stage.

The yellow top will reach an SoC of 95% in under an hours driving, three times sooner than a DC/DC device will take, BUT, just like a DC/DC device, the last 5% of the charge will now take at least another 3 hours of driving.

This is why a realistic common reference point in the state of charge of the battery is set 95% is used as an example of the way both types of systems can charge the auxiliary battery. And from this reference point, you can clearly see that there is a huge advantage for using one of our systems over the restricted charging a DC/DC device offers, and our systems are heaps cheaper to set up.

[DunnToImpress]

Hello Tim, I am having a bit if an issue with my Traxide set up. I am giving the Auxilary Battery a bit if a tickle up using a battery charger through the Anderson plug at the back of the vehicle. The auxilary battery is now up to float but the Cranking battery doesnt seem to be getting any charge, it is sitting at 12.4v and not moving. i have tried the switch on the dash in both positions but no result.

Should the Cranking battery be accepting charge or am i wrong???

Look forward to hearing back from you,

Rohan

[austastar]

Hi,
If you charge the aux battery directly and the vsr is open, (light flashing) no current can pass to the cranking battery.
To charge both batteries, charge the cranking battery. At the correct voltage, the vsr will close (light not flashing) and the aux battery will now charge in parallel with the cranking battery.
Cheers

[drivesafe]

Hello Tim, I am having a bit if an issue with my Traxide set up. I am giving the Auxilary Battery a bit if a tickle up using a battery charger through the Anderson plug at the back of the vehicle. The auxilary battery is now up to float but the Cranking battery doesnt seem to be getting any charge, it is sitting at 12.4v and not moving. i have tried the switch on the dash in both positions but no result.

Should the Cranking battery be accepting charge or am i wrong???

Look forward to hearing back from you,

Rohan
Hi Rohan, which isolator do you have and how old is it?

[DunnToImpress]

It's a USI-160 probably about 6 years old now.

[drivesafe]

Hi Rohan, first make sure the switch on the In-Cab module is set away from the LED.

Then start your motor and let it run till the LED glows constantly.

Once it does, turn you motor off.

You can then charge both batteries via the rear Anderson plug.

The USI-160 has a 72 Hour shut-down and as long as you connect the charger up every day or two, both batteries will be charged each time.

If you leave it for more than 3 days, the USI-160 turns off as an energy saving function, just follow the above again.

[DunnToImpress]

Thanks Tim, It is surely a thing of beauty!! Ran the car for a few minutes and then shut it down and connected the Charger to the Anderson Plug. Cranking Battery went to 14.9v and has stayed there for about an hour now, getting a good charge. Thanks for your help with this. I sort of thought it should charge this was as it has in the past when using a Solar panel. The car was run this morning so not sure why it didn't charge straight through before?? I have tried it a few times over the last few days with no good results either. anyway, appreciate your help,

[DiscoMick]

The Traxide will not connect your batteries unless your starting battery is well charged - I forget the exact level but it is about 80% I think.

[drivesafe]

Thanks Tim, It is surely a thing of beauty!! Ran the car for a few minutes and then shut it down and connected the Charger to the Anderson Plug. Cranking Battery went to 14.9v and has stayed there for about an hour now, getting a good charge. Thanks for your help with this. I sort of thought it should charge this was as it has in the past when using a Solar panel. The car was run this morning so not sure why it didn't charge straight through before?? I have tried it a few times over the last few days with no good results either. anyway, appreciate your help,
Sounds like your batteries may need a fair bit of maintenance charging.

It is unusual for the USI-160 to shut down in such a short time, unless the batteries are in a low state of charge.

Keep putting the solar on as often as possible, over the next week, and then see how long the USI-160 stays on.

[DunnToImpress]

Thanks Tim, yes thew car has been doing a fair bit of short run work and not getting nay good Highway time, also my battery charger has been out of action. The charger is now up and going so will get some quality charging back into the Cranking Battery again over the coming week or so. Thanks again for you help, talk more soon.

[drivesafe]

Keeps us informed on how your battery responds to some charging.

[scarry]

The Traxide will not connect your batteries unless your starting battery is well charged - I forget the exact level but it is about 80% I think.

If it’s an SC80 out at 12.0V,in at 13.2V.

[DunnToImpress]

Just thought i would give a follow up message on my Batteries.
I have been using the Aux Battery to charge my Electric Golf Buggy Battery, through an inverter to the 24v charger. I put the Buggy on charge when i finish golf, then have drinks and a sandwich at the club, the drive home is about 30 minutes. I then remove the charger and turn it back on when going to golf again. This gets the golf buggy fully charged but with the other short runs i have been doing the car and aux batteries havent been getting up to full charge. The Corona situation has also meant my drive to golf is about 20 minutes instead of 30-40!!!

I now have the Car Batteries on charge, they charged for about 16 hours overnight on Sunday and then 6 hours each on Monday and Tuesday. I rest them overnight and the Tuesday morning cranking battery level was 12.64v showing 94%, the Wednesday morning battery level 12.68v showing 99%. I will try to keep charging for 6 hours or so each day during this week and see how they go next week. I am aiming to also reduce the short runs in the car as it doesn't seem do it any good.

[vpnong]

I have a Discovery 4 HSE 2012. In 2013 I put my car in Sydney garage to get a second car key from England. They had to re-program for both keys then issue appeared. The security unit required to be updated because it could not sync to the new key to recognize it. They replaced new unit then every thing was working perfect. A month after that time, message "Low battery please start engine" starting often until now 2021. Even I replace many batteries reset BMS but it still displays message if radio is on for 5 minutes or doors is not close properly. Check alternator it works well when charge = 14.4 volt and battery after stop charging = 12.6 volt. If no message displaying, battery is fine not dropping voltage. If there is a message, then battery voltage drops quick to 12.2 v. I believe that the security unit is still on and consume energy much. It supposes to sleep when lock until a trigger from door access to wake up.
The question is what trigger the message to display? Why if there is no message so I can start its engine after one and half month never using it even in cold whether.
Likely the message is not only in LR4 but on the entire Land Rover cars have the same problem with the design.
Thinking of buying a new Defender but I hate to see this problem again. LR doesn't want to fix it at all not like Toyota or Nissan...They laugh at buyers and saying "THEY ARE IDIOTS".

[Tombie]

Nissan and Toyota have lots of “don’t want to fix it” episodes - far worse and more frequent than LR.

Your low battery issues will be after multiple short drives. Nature of any vehicle.

[drivesafe]

How to do a LOAD TEST on your cranking battery at home.

Have a look at the link below but before ( and after ) you do the Battery Maintenance Procedure, carry out this simple but accurate Load Test.


This LOAD TEST is carried out for two reasons.

First off, the Load Test will tell you if your cranking battery is still good.

Second, if you carry out a load test at the beginning and at the end of a full week of Maintenance cycles, your will also see if the Maintenance charging has worked.


To carry our a Load Test, if you have a dual battery setup, first disconnect the Negative ( - ) battery lead on your AUXILIARY battery.

NOTE, if you have one of my new isolators ( supplied from the 01/01/22 ), you can simply switch the isolator to the LOCKED mode and the two batteries will be automatically disconnected and removes the need to disconnect the negative lead on the auxiliary battery.

Next, with a digital multi meter, note the voltage of the cranking battery.

Now turn your ignition on but DO NOT START YOUR MOTOR.

With the ignition ON, turn your headlights on.

Again, note the voltage at your cranking battery.

Note the voltage every minute for the next 5 minutes.

Regardless of what the voltage is, as long as it only drops for about the first two or three minutes and then levels out, your battery is good.

If the voltage continually drops over the 5 minute period, then your battery is probably on its way out.

After the 5 minute test, turn every thing off and reconnect the Auxiliary battery’s Negative leads or unlock the isolator.

Now over the next week, follow and carry out the Maintenance procedure described in the link bellow.

After the week of Maintenance cycles, carry out another Load Test and compere the voltages from the first teat to the last test.

See if the voltages are now higher than those when you did the first Load Test.



Scroll down the page till you get to “Battery Maintenance”
https://www.aulro.com/afvb/the-verandah/246755-line-auto-electrical-info-8.html

[drivesafe]

A lot of care must be used when selecting a lithium battery as an auxiliary battery.

SPECIAL NOTE, lithium batteries should NEVER be used as a cranking battery.

The primary difference between charging a lead acid battery and a lithium battery is that a lead acid battery requires three stages of charging, Bulk, Absorption and a Float charge.

Whereas Lithium Batteries require two stages of charge, Bulk and Absorption, and once charged, the charging source must turned off.

ALSO NOTE it is very rare for a Lithium battery’s BMS to act as a current limiter during charging, In other words, the lithium battery’s BMS does not shut down the battery once it is fully charged.

Many Lithium Battery BMS will shut the battery down if there is a high current DISCHARGE, this has nothing to do with charging.

The above info relates to charging with a DC/DC device, Solar Regulator and a 240vac Battery Charger, it has little to do with charging from an alternator.


ALTERNATOR CHARGING OF LITHIUM BATTERIES.
There are a number of specific requirements when charging lithium batteries directly from an alternator.

First and foremost, when selecting a lithium battery for charging directly from an alternator, with a Discovery 2 or 3, the battery MUST HAVE a CONTINUOUS CHARGE CURRENT rate of at least 100 amps.

NOTE this is NOT the MAXIMUM charge current makes on a lithium battery, as this is something a lithium battery can only tolerate for a very short time of a few seconds to a few minutes.

If you have discharged a lithium battery to a low state and you then drive for a few hours, the battery could be receiving a charge current as high as 100 amps for quite some time.

Note, this does not apply to a Discovery 4 or any vehicle with a SMART alternator function.

I have tested charging a Lithium battery with a 140 amp alternator and with a 100Ah lithium battery mounted in the rear of the vehicle and Twin 6B&S ( 13.5x2 ) cabling connecting the lithium battery, via a DT90 isolator, to the cranking battery.

While I monitored the currents in both directions ( Charging and discharging ) I would periodically blow a 50 amp fuse but an 80 amp fuse allowed 70+ amps of continuous charging and up to 140 amp discharging while starting the motor.

How fuses work is for another time.

I could change the operation of the alternator in the vehicle I used, from a SMART alternator function, similar to a D4, to a Variable Voltage alternator function, similar to how a D3 alternator works.

My tests were two fold. They were to see how my SC90 and DT90 isolators worked with a lithium axiality battery and how well a lithium battery could be charged with an alternator.

When charging a lithium battery from an alternator, you do not have to worry about shutting the charging off once the lithium battery is fully charged as this will happen every time you turn your motor off.

Constant charging of a fully charged lithium battery from an alternator would only be a problem if you were to regularly drive for 10 to 15 hours straight. Not likely to happen.

My findings were that my isolators worked fine with a lead acid cranking battery and a lithium auxiliary battery but I got some interesting results relating to using a Lithium Auxiliary battery.

First off, because lithium batteries have a higher and constant rested voltage ( around 13.2v -13.4v ) my isolators would remain on, regardless of whether they were set to Ignition mode or Shared mode.

So when I turned the motor off, with the lithium auxiliary battery sitting at 13.3v, and the lead acid cranking battery sitting anywhere from about 12.3v to 12.7v, the lithium would slowly discharge back into the cranking battery.


I used this setup for a little over two years.

The alternator operating in Variable Voltage mode, would really get much over 14.0v and regularly settled down to 13.5v, while driving.

This still allowed the lithium battery to be fully recharged ( 95% or higher ) even after short drives.

NOTE, the cranking battery was on its last legs and beginning to fail to start the motor, through age, when I first put the lithium battery in.

As I stated, the lithium battery was used in this setup for a little over two years, but with in a few days of installing the lithium auxiliary battery, the cranking battery’s starting performance improved dramatically.

After having the lithium auxiliary battery in for two years, I decided to remove it to carry out a fully monitored bench discharge test.

The lithium battery still had a 100% capacity.

But the surprising thing was that the “STUFFED” cranking battery lasted another 6 months and I only replaced it when my BM2 Bluetooth Battery Monitor warned me that the cranking battery voltage went too low when starting the motor.


Now when camping, with two lead acid batteries, the cranking battery and the auxiliary battery, while camping, your fridge, camp lighting, phone and computer charging, etc, current would be shared and come from both batteries.

With a lead acid cranking battery and a lithium auxiliary battery, all the power would initially be coming from the lithium battery even though the two batteries are still connected.

Only if the lithium battery was discharged down to about 15 to10% SoC, would power start coming from the cranking battery.

In this situation, the DT90 isolator still protected the cranking battery from being over discharged and the DT90 would completely shut down before the Lithium Battery’s BMS shut the Lithium battery down.

When you went for a drive, even with both batteries discharged to their lowest allowed level, both batteries would be back over 95% in about 90 minutes.

If you decide to use a lithium battery as an auxiliary battery, you could use two lithium batteries with a continuous charge current of 50 amps, as long as they are wired in PARALLEL.

[austastar]

Hi,
I had the SC80 for 10 years with a lead house battery and the connection to the tray camper was at the back of the ute cab. This I used for the main current supply when I mounted the dc-dc near the Li battery in the camper.
I could have also taken the ign switch wire for the dc-dc from there but decided on the extra safety of sourcing the power from the ignition, but just on a whim, didn't.
Cheers

[drivesafe]

Hi,
I had the SC80 for 10 years with a lead house battery and the connection to the tray camper was at the back of the ute cab. This I used for the main current supply when I mounted the dc-dc near the Li battery in the camper.
I could have also taken the ign switch wire for the dc-dc from there but decided on the extra safety of sourcing the power from the ignition, but just on a whim, didn't.
Cheers

A little tip for anybody fitting a DC/DC device to any vehicle with a SMART alternator operation.

You MUST use a DC/DC device that can be controlled by the vehicle's ignition, as austastar has done.

If you just depend on the Voltage Sense input on a DC/DC device, these devices can shut down if the alternator voltage gets too low, while you are still driving.

Where possible, if the vehicle has the STOP/START function, it is a good idea to use the vehicle's FRIDGE circuit for the DC/DC device Ignition control, as this will shut the DC/DC device down while you are stopped, like at a set of traffic lights or sopped in a traffic jam.

[CrankAnxiety]

Hi @drivesafe and everyone else.
I've purchased a Disco 4 that has a Traxide SC-80 in it.
It has an 12v female cigarette lighter port in the rear on the right hand side (I'm assuming it's not factory and is part of the dual battery install).

I've purchased this solar trickle charger (https://www.bcf.com.au/p/hardkorr-15w-12v-solar-trickle-charger/648833.html?utm_content=paidsearch-pmax&gad_source=1&gclid=Cj0KCQiA6Ou5BhCrARIsAPoTxrCCKZKfMHcFPKw0Pvtk cNTbQhHhVKlZNdRDEqIDJQsFR53YnwvG1ngaAgZpEALw_wcB&gclsrc=aw.ds), and I'm planning to use it to combat my "Shopping Trolley Syndrome" (infrequent short trips).

My plan is keep the solar panel inside the car, on the dash, and run the cable to the rear 12v cigarette lighter port mentioned above. Presumably this port is always on, even when the car is off, is that correct?

Will this 12v port charge both the crank and aux batteries? A friend was curious about your recommendation of connecting the trickle charger to the auxiliary battery rather than the crank battery, why did you recommend it that way?

Finally, do you have an owner's manual for the SC-80 so I can understand more about how it works, and fully understand the in cabin switch's purpose?
Thank you in advance.

[drivesafe]

Hi @drivesafe and everyone else.
I've purchased a Disco 4 that has a Traxide SC-80 in it.
It has an 12v female cigarette lighter port in the rear on the right hand side (I'm assuming it's not factory and is part of the dual battery install).

I've purchased this solar trickle charger (https://www.bcf.com.au/p/hardkorr-15w-12v-solar-trickle-charger/648833.html?utm_content=paidsearch-pmax&gad_source=1&gclid=Cj0KCQiA6Ou5BhCrARIsAPoTxrCCKZKfMHcFPKw0Pvtk cNTbQhHhVKlZNdRDEqIDJQsFR53YnwvG1ngaAgZpEALw_wcB&gclsrc=aw.ds), and I'm planning to use it to combat my "Shopping Trolley Syndrome" (infrequent short trips).

My plan is keep the solar panel inside the car, on the dash, and run the cable to the rear 12v cigarette lighter port mentioned above. Presumably this port is always on, even when the car is off, is that correct?

Will this 12v port charge both the crank and aux batteries? A friend was curious about your recommendation of connecting the trickle charger to the auxiliary battery rather than the crank battery, why did you recommend it that way?

Finally, do you have an owner's manual for the SC-80 so I can understand more about how it works, and fully understand the in cabin switch's purpose?
Thank you in advance.
Hi CrankAnxiety, because the regulator for the solar panel is at the solar panel, you need to keep the cable run from the solar panel to the battery as short as possible.

The reason for this is that voltage drop caused by the cable run from the solar panel to the battery can be such that the battery may not get as high a charge as is needed to properly charge the battery.

Its not a big potential problem but one that can be improved on by running the cable from the solar panel, through the firewall, to either battery, but the auxiliary battery would be the best choice because you can not connect the negative from the solar panel to the cranking battery's negative terminal.

You can connect to both terminals on the auxiliary battery, so it makes it easier.

BTW, don't forget to set the switch on the SC80's In-Cab module towards the LED ( STORED mode )when your D4 is not being driven much but you are using the solar panel to keep the batteries charged.

This will give you the most efficient charging from that small panel.