Lithium batteries cannot just drop in and replace lead batteries can they?

[Geistguy]

I have just fitted a 300ah Fogstar to our 2019 Pilote, all I've done is alter the battery type setting to lithium and it works fine. It charges quickly while driving and the 120 watt solar panel tops it up adequately.

 

[Pausim]

I haven’t bothered changing the mains charger on my Carthago. Yes it slightly undercharges the LiFePO4 battery but you don’t need a full battery when on EHU and undercharging does no harm at all. You have solar and B2B which are the important bits when not on EHU.

 

[AshVanBitz]

I came across this article Here

I know its specific to Sargent's EC325 PSU but it shows not all motorhomes are the same and we have to tread carefully when making any modifications to the electrical system.

You should not connect any device direct to the battery on the EC325.​

The Sargent EC325 unit has a very sophisticated mains charger. If 240v is connected and the battery is low it will 'isolate' the battery from the Motorhome and switch a small 12v power supply into it's place to keep things ticking over.​

It will then 'super charge' the battery at up to 18v and 25amps. Anything connected directly to the battery will get hit with these higher volts.​

A Battery Master style unit should not be fitted, for obvious reasons.​

​

Because the charger voltage can reach 18v, a Gel or AGM battery should not be used for the habitation battery. Ideally it should be a Silver technology based battery like the Varta LFD90 as these will cope with 18v charge better than most.​

Good morning Diabalo,
The Battery Master is perfectly fine to be fitted to any vehicle utilising the Sargent equipment (hundreds and hundreds have been fitted over the back 25+ years). The Battery Master itself is wired to the feeds coming from both the engine and leisure batteries and not the Sargent system directly. It's own internal resistors and diodes protect it from any surges.

 

[Diabalo]

Good morning Diabalo,
The Battery Master is perfectly fine to be fitted to any vehicle utilising the Sargent equipment (hundreds and hundreds have been fitted over the back 25+ years). The Battery Master itself is wired to the feeds coming from both the engine and leisure batteries and not the Sargent system directly. It's own internal resistors and diodes protect it from any surges.

And a good morning to you AshVanBitz

The problem with the internet is filtering out the good and bad advice that's out there. I came across this article while trying to sort out a friends EC328 problem. It's helpful when knowledgeable people like your good self can provide the correct information.

What I was really trying to do was give an example to what you said in post #16

 

[DavidCh]

Thats just scaremongering, no BMS if I remember. Weve had no issues and as I said the solar does most charging.

I agree with you, this is a particularly impressive display of what could go wrong and its not relevant if a BMS is fitted or not as it will still pull the power (although you could obviously restrict the charge rate with good BMS) and is very unlikely in the real world. What it does demonstrate is that there is more to the electrical system than simply changing a battery that needs to be considered, particularly the cabling and the alternator size. For example, on our van, the cable that was being used to charge the house battery through the split charge relay would have been questionable for a Christmas tree light! Same issue on the solar before I fixed it, very impressive cable from the panel to the charge controller, and again from the controller to where it disappeared into the paneling. Same cable going to the battery. Further investigation found a connector to a very thin cable for the couple of metres behind the panel to make it easier to pull it through! Fire here we come!

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[peterc10]

I suppose that the answer to the original post is "maybe". But if you do just drop it in to most motorhomes it will may mean you will not get the best out of the lithium batteries and you may shorten their lives and cause problems elsewhere. Given that the cost of the lithiums is much more than the cost of carefully making a few more changes, I decided to make those changes, with the guidance of people on here. For those reasons I chose KS batteries but took the "drop in" advice with a pinch of salt.

As an example. As I understand it Lithiums are very fast chargers and, unlike lead based batteries, they have low resistance, which does not change when they start to get full. The KS video I saw showed them sucking out huge amounts of amps from the alternator with the motorhomes engine running. Good advert for getting lots of charge in quickly but potentially not good for the long term health of my non-smart alternator. So I installed a B2B, which probably cost a lot less than a new alternator in the future, but which slowed down the charge rate to one that I thought was a more sensible compromise.

 

[eddie]

I am a high power user, I can use my camper electric only, air con, heating, cooking water heating the lot

I use huge amounts of power, but equally can charge at 120 amps from my 220 amp alternator none of this would be possible had I not spec'd my camper properly

To those that say theirs works and solar keeps everything topped up great, come with us to Norway this Winter and I'll see how we'll your solar is doing and your 20 amp split charge relay

What will actually happen the first time your 300 amp lithium is 60% discharged and you start the engine the 100 odd amp maximum charge the battery can handle will melt everything

 

[68c]

So you fit a lithium battery as it will charge quickly then fit a device to reduce the charge current.

 

[peterc10]

So you fit a lithium battery as it will charge quickly then fit a device to reduce the charge current.

If that was aimed at me, the answer is yep. But very fast charging via the alternator was always low down on my list of reasons for wanting lithiums.

Much further up the wants list was faster discharge for short bursts for hair dryer, toaster, microwave and kettle (in that order of priority). We are not as power hungry as eddievanbitz and are happy to pay for gas for cooking, fridge and heating if need be. And as for Norway in the winter, no way Jose. Put it this way, my wife is the only woman I know who uses an electric blanket in August. Edit: and I am getting that way too

In reality with 450W solar on the roof in the places we visit and the seasons we do so means that the batteries are almost full before we pull off the aire/wild spot etc in the morning. So the B2B does not need to pull as many amps as the batteries want it to, and that will be kinder to my humble little alternator

 

[Lenny HB]

So you fit a lithium battery as it will charge quickly then fit a device to reduce the charge current.

You fit a device to stop burning out your alternator.

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[Raul]

So you fit a lithium battery as it will charge quickly then fit a device to reduce the charge current.

You slow it down to a safe level for your alternator, but still much faster than a split charge system. My B2B is switched of in summer, and I go trough a bit of electricity. There are other ways to charge fast, not just the B2B, but if you are keen, just change to a high output alternator.

 

[Brianmor]

Which Victron b2b would people recommend for my setup of Sargeant 328,
100w solar, Victron 75/15 mppt on a non smart alternator, their range is confusing me.
Thanks

 

[Lenny HB]

Which Victron b2b would people recommend for my setup of Sargeant 328,
100w solar, Victron 75/15 mppt on a non smart alternator, their range is confusing me.
Thanks

Victron only make one B2B a 30 amp one avaliable in isolated and non isolated version you need the non isolated.

 

[Brianmor]

Victron only make one B2B a 30 amp one avaliable in isolated and non isolated version you need the non isolated.

Thanks for the reply, I presume that as long as I increase relevant cables then my alternator and battery will be safe

 

[Lenny HB]

Thanks for the reply, I presume that as long as I increase relevant cables then my alternator and battery will be safe

Yep

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[Brianmor]

Yep

Thanks very much for the help

 

[Hoovie]

Victron only make one B2B a 30 amp one avaliable in isolated and non isolated version you need the non isolated.

That is not actually strictly correct.
The Device that people refer to as the "Victron B2B" is a Orion Tr-Smart DC-DC converter. There are quite a few versions of these... 12V-24V, 24V-12V, 24V-24V and 12V-12V.
Taking the most usual 12V-12V one, there is the 30A one that most people think of, but also a 18V one (I have one of those actually).
I use mine as a regulated PSU, but I could use it as a B2B, just like the 30A one can be used in both ways.

If someone has the isolated version, it can be used as a non-isolated version easily by just linking the two -ve terminals together. Will work just the same.

 

[bigtwin]

the first time your 300 amp lithium is 60% discharged and you start the engine the 100 odd amp maximum charge the battery can handle will melt everything

I’m not sure that I understand what you’re saying. Are you saying that despite having a, say, 110A alternator, the downstream wiring (and fusing) is not rated to handle the full alternator output current.

If that’s the case, that‘s a fundamental, and dangerous, design flaw.

Ian

 

[peterc10]

I’m not sure that I understand what you’re saying. Are you saying that despite having a, say, 110A alternator, the downstream wiring (and fusing) is not rated to handle the full alternator output current.

If that’s the case, that‘s a fundamental, and dangerous, design flaw.

Ian

As I understand it the wiring will work with the split charge relay because there is a built in limit to the rate of charge. So it works as designed, but has a low rate of charge. But once you by-pass the split charger with a B2B and insert lithium batteries which have lower resistance than lead acid that increases the current beyond the capacity of the existing wiring. That is not the converter's fault if the whole thing melts because you have changed their design.

 

[Lenny HB]

I’m not sure that I understand what you’re saying. Are you saying that despite having a, say, 110A alternator, the downstream wiring (and fusing) is not rated to handle the full alternator output current.

If that’s the case, that‘s a fundamental, and dangerous, design flaw.

Ian

The wiring was never desgined to handle the high currents a Lithium can take.
Most German vans you will be OK as the split charge wiring is normally 16mm sq, it will get hot and you will get a bit of a volt drop but it won't go up in smoke.
British built vans with their pathetically undersized wiring is a different case.

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[eddie]

I’m not sure that I understand what you’re saying. Are you saying that despite having a, say, 110A alternator, the downstream wiring (and fusing) is not rated to handle the full alternator output current.

If that’s the case, that‘s a fundamental, and dangerous, design flaw.

Ian

What I am saying is a Lithium battery is a sponge, and if it’s maximum charge rate is 100amps and you have a ’standard’ split charge system which is a cheapo relay costing a quid or so putting the engine battery and the leisure battery in parallel when the engine starts, connected by a long wire (too long) that’s about as thick as a boot lace, then the ‘sponge’ will be looking for a charge of, or up too 100 amps.

The (what’s called laughingly) split charge system will either melt somewhere, or, if it’s fused blow the fuse.

Most split charge fuses are rated at 20 - 25 amp. The BMS ((Battery Management System) will protect the battery from dangerous input/output requests but cannot detect that a 30 amp automotive relay designed to blow air horns or fog lights is getting dangerously hot For example.

Split charge systems have always been shit, and now lithium batteries are available split charge systems are dangerous shit.

 

[eddie]

That is not actually strictly correct.
The Device that people refer to as the "Victron B2B" is a Orion Tr-Smart DC-DC converter. There are quite a few versions of these... 12V-24V, 24V-12V, 24V-24V and 12V-12V.
Taking the most usual 12V-12V one, there is the 30A one that most people think of, but also a 18V one (I have one of those actually).
I use mine as a regulated PSU, but I could use it as a B2B, just like the 30A one can be used in both ways.

If someone has the isolated version, it can be used as a non-isolated version easily by just linking the two -ve terminals together. Will work just the same.

Victron make their buck boost DC-DC chargers up to 100 amp

Van Bitz stock them

Buck-Boost DC-DC Converter 25A / 50A / 100A - Victron Energy

Charge a 12/24V service battery in vehicles with an intelligent dynamo using the Buck-Boost DC-DC Converter. Find a dealer near you.

www.victronenergy.com

 

[Pausim]

I like my Votronic B2B because it has a good range of charging profiles, including 4 different LiFePO4 profiles. This suits the slightly different charging requirements of different battery manufacturers ranging from 13.9V (discontinued Dometic) to 14.6V Relion.

 

[nickq]

When the B2B is installed the standard split charge is disconnected. In turn a large amount of vehicles lose their D+ and along with it the ability to switch the fridge over to battery when the engine is started. Whilst carrying out the installation of the B2B the original cabling needs to be modified so the D+ can be powered off the leisure battery(s). This doesn’t apply to every motorhome but it is becoming increasingly more common.

In my van I believe the DS300 supplies power to the fridge from pin 2 on connector 17.

Annoyingly it is just about impossible to trace the wires after they dissapear down that gap. I would have to remove most of the woodwork and possibly one of the 2 fresh water tanks (it's a split tank setup).

The top wire on B1 with the silver tape is the solar feed for the starter battery. The regulator (NDS320) is just to the left. The top wire on B2 is the solar feed for services battery.

The wire that appears at the services battery is 8.5mmsq. I'm guestimating this is no more than 5m away so this should be good for 30A (2.36% drop).
I do have R37 so intend of snipping this to disable the split charge relay and installing the B2B.

I believe the 2 relays (V23086) next to connector 17 are the AES bridge, which the manual states connects the fridge directly to B2. So I guess this is your point of the fridge being supplied by B2 as when the split charge relay is disabled, B2 is no longer in parallel with B1 and is only supplied by the B2B.

The green wires are the simulated D+ so I should be able to use this to trigger the B2B.

So for these reasons I need to situate the B2B by the DS300, there will be no D+ near to the services battery, also this will prevent the current to power the fridge from travelling the cable from the services battery. I am not bothered about fast charging from the alternator, but powering the fridge adequately is of course required. My fridge is the Thetford N3000 Model B which I believe can draw up to 15A.

So in summary I think the 30A B2B installed by connecting input to B1 and output to B2 of the DS300 and removing R37 to disable split charge should be good. Up to 15A could go to the fridge from the DS300 directly fed from the B2B->B2 leaving 15A possible to charge the services battery via B2. Curious that they fit a 30A fuse for the fridge, seems a bit large to me.

Does this make sense?
Thanks.

 

[Hoovie]

Victron make their buck boost DC-DC chargers up to 100 amp

Van Bitz stock them

Buck-Boost DC-DC Converter 25A / 50A / 100A - Victron Energy

Charge a 12/24V service battery in vehicles with an intelligent dynamo using the Buck-Boost DC-DC Converter. Find a dealer near you.

www.victronenergy.com

Good point.
Do you sell many though? They are stupidly expensive.

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[MisterB]

I am considering getting my NE237 control unit 'altered' by Apuljack to sort out the split charge issue. To me it's worth doing as it will settle my mind on whether I need to do anything or not!

Is there a Funster discount or coupon that anyone knows of?
Has anyone had theirs 'altered' ?

 

[Pausim]

In my van I believe the DS300 supplies power to the fridge from pin 2 on connector 17.

I have no problem with my DS300 since fitting a B2B. I separated the leisure and engine batteries with a new relay at +B1. The DS unit and its functions continue to be powered by the leisure battery which is getting a good direct charge from the B2B. The original relay simply joined the 2 batteries which meant the DS was powered by whichever battery had the highest voltage, my modifications have made no difference to the fridge operation on 12V.

 

[AshVanBitz]

In my van I believe the DS300 supplies power to the fridge from pin 2 on connector 17.
View attachment 761861
View attachment 761862

Annoyingly it is just about impossible to trace the wires after they dissapear down that gap. I would have to remove most of the woodwork and possibly one of the 2 fresh water tanks (it's a split tank setup).

The top wire on B1 with the silver tape is the solar feed for the starter battery. The regulator (NDS320) is just to the left. The top wire on B2 is the solar feed for services battery.

The wire that appears at the services battery is 8.5mmsq. I'm guestimating this is no more than 5m away so this should be good for 30A (2.36% drop).
I do have R37 so intend of snipping this to disable the split charge relay and installing the B2B.

I believe the 2 relays (V23086) next to connector 17 are the AES bridge, which the manual states connects the fridge directly to B2. So I guess this is your point of the fridge being supplied by B2 as when the split charge relay is disabled, B2 is no longer in parallel with B1 and is only supplied by the B2B.

The green wires are the simulated D+ so I should be able to use this to trigger the B2B.

So for these reasons I need to situate the B2B by the DS300, there will be no D+ near to the services battery, also this will prevent the current to power the fridge from travelling the cable from the services battery. I am not bothered about fast charging from the alternator, but powering the fridge adequately is of course required. My fridge is the Thetford N3000 Model B which I believe can draw up to 15A.

So in summary I think the 30A B2B installed by connecting input to B1 and output to B2 of the DS300 and removing R37 to disable split charge should be good. Up to 15A could go to the fridge from the DS300 directly fed from the B2B->B2 leaving 15A possible to charge the services battery via B2. Curious that they fit a 30A fuse for the fridge, seems a bit large to me.

Does this make sense?
Thanks.

Good morning nickq,

To be honest this looks overly complicated for what you are trying to achieve. If you have the time, give me a call later this afternoon on 01823321992 and I will get Dave (my workshop manager) to have a conversation with you. Where I have all the beauty , he certainly has the brains of this operation and he can discuss what options you have available and how to do it in an easier fashion.

Ash

 

[eddie]

Good point.
Do you sell many though? They are stupidly expensive.

I’m retired I sell nothing

Van Bitz keep a huge array of equipment so they can install what the customer wants or which is best for the customer

Sometimes not the same thing

 

[KLWinton]

Doing all this just now in my Elddis 255. Replaced the solar charger to a Victron MPPT and switched the Schaud to lithium. Doing a straight replacement PS306 in the PDU to an apuljack lithium replacement so everything is lithium comparable and can easily be put back to normal should I change the MH sometime in the future.

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