Changing varta 92 ah battery for a 150ah lithium in g c 600

[RachelD]

Hi, I have tried this myself, I have an eco tree lithium battery which I've used on a previous motorhome.
So .....
You can do it, however there are some things you need to be aware of ...

You can simply swap out the battery under the bonnet (Habitation) battery with the Lithium battery.
Everything will work, as with the AGM battery .....

EXCEPT FOR ..

The Battery charge indicator on the control panel will show the battery as being 'full' pretty much until it isn't, this is something that you can't change (without re-coding the vehicle software) which is not easy to do.
The lithium battery will ONLY charge when the 'fast charge' button is pressed on the dashboard.
The Lithium battery will drain very quickly (20+ amps) as soon as the engine is stopped after it has been on charge using the method above.
You MUST stop the engine, with off the ignition and then it will stop discharging.

I tried it for a few months and I've now re-fitted the original AGM battery as the lithium battery just created other problems which I felt weren't worth the benefits.

So, in short, yes, a direct replacement is possible if you're happy to put up with the issues above.

I've added a second battery in the rear cupboard by changing the battery isolator to a 1, 2 & 1+2 selector switch, it then increases the capacity by 100% so around 100ah which is fine for 2 nights off-grid, using fridge and lighting, TV, charging devices etc.

If you need more than this 'off-grid' time you can have a lithium system fitted which replaces the charging (DC-DC) MPPT if you have solar, and so on, but they come at quite a high premium.

Hope this is helpful to you in some way.

I have a question:
The GC seems to have a VSR for dealing with charging the leisure battery when driving, and separately a solar charge controller for the rest.

I have fitted a solar system to my T5.1 which is 240w solar to a lithium battery which is charge controlled by a CTEK d250se. The CTEK handles both split charge and solar and will charge the starter battery as well if the leisure battery is full.
It’s £250 and siting it/wiring it may be a challenge but theoretically it should avoid all the problems except the display issue. It has a control wire for the smart alternator issue as well.

This would eliminate/replace the votronic in the back and the split charge relay wherever that is

Have I missed anything before I start scratching my head about where to hide the CTEK and run the inevitable extra cables?

 

[leeb]

Not sure I understood all above...but I'm pretty sure I've located the split charge relay in the GC.
As you look at the leisure battery from the front of the vehicle it's bolted to the inside of the engine bay just behind and to the right of the leisure. There is a grey cover with a plus sign behind the leisure battery...lift this off and it's easy to see the relay. Photo below

 

[G-A-R-Y]

Good man, I've asked lots of times for this units location.

 

[leeb]

My pleasure...my natural curiosity will get the better of me eventually!!

 

[G-A-R-Y]

So if this is indeed a dumb relay and rated at 150amp with associated wiring it would be an ideal place to fit/replace a B to B using those two connections. I already have a Renogy 40amp B to B. And if it's a bump relay ignition controlled that would activate the Renogy.
Any input please.

 

[leeb]

I'm not an auto electrician...I do have a reasonable understanding of circuits. The two large cables (I think 25 mm sq) entering the relay do seem to provide an obvious link between leisure and crank battery to insert a dcdc charger. There is also a plug connecting fine control cables at the left hand side...not sure what these do.

 

[leeb]

G-A-R-Y
Found this....it's a thread in the Transporter forum explaining in detail how to exchange the exact same split charge relay for a dcdc charger in the transporter van

https://vwcaliforniaclub.com/thread...arger-to-replace-vw-split-charge-relay.23466/

Of use!?

 

[G-A-R-Y]

The link doesn't work??

 

[leeb]

It's a posting by "Loz"...Thread 'How-To install DC-DC charger to replace VW Split Charge relay' https://vwcaliforniaclub.com/thread...arger-to-replace-vw-split-charge-relay.23466/

 

[G-A-R-Y]

It's a posting by "Loz"...Thread 'How-To install DC-DC charger to replace VW Split Charge relay' https://vwcaliforniaclub.com/thread...arger-to-replace-vw-split-charge-relay.23466/

Thanks, I've read most of that. At least VW gave us the boost switch.

 

[leeb]

All solved by using a small father/son outfit near Wantage, Off grid Power Solutions.
Replaced leisure with a 150Ahr LiFePO4 battery, replaced split charge relay with victron 50A DCDC charger and reprogrammed Votronic MTTP solar controller to Lithium. All work completed in a matter of hours. Battery has a bluetooth output to monitor charge/draw and level.
All works impressively well. Battery charge level around 60% on installation, by the time I had driven home (3 hours) the battery had soaked up the 60 or so Amps required to be fully charged. They did the whole job in a few hours and with no new holes drilled etc it would be possible to reinstall the old set up should you ever wish to do so! Not sure what the GC control panel will make of this but I will report back after our upcoming trip to France.
Photos below

 

[GordonH]

Has the GC’s KFG been recalibrated for the 150Ah ?

 

[leeb]

No idea what this question means...not being difficult but what is KFG?

 

[GordonH]

Sorry, wasn’t trying to be awkward. The KFG is the GC’s control unit that measures the battery usage. The small white box on the negative terminal of the battery is the shunt its uses to measure the current and hence Ah. As I understand the system the control panel % is communicated from the KFG and is based on the Ah remaining so it will read incorrectly unless the KFG knows it has a different capacity battery.

 

[Californication69]

All solved by using a small father/son outfit near Wantage, Off grid Power Solutions.
Replaced leisure with a 150Ahr LiFePO4 battery, replaced split charge relay with victron 50A DCDC charger and reprogrammed Votronic MTTP solar controller to Lithium. All work completed in a matter of hours. Battery has a bluetooth output to monitor charge/draw and level.
All works impressively well. Battery charge level around 60% on installation, by the time I had driven home (3 hours) the battery had soaked up the 60 or so Amps required to be fully charged. They did the whole job in a few hours and with no new holes drilled etc it would be possible to reinstall the old set up should you ever wish to do so! Not sure what the GC control panel will make of this but I will report back after our upcoming trip to France.
Photos below

View attachment 128239

View attachment 128240

Looks like a nice easy solution.
I’m interested, as will be looking at a new Cali or James cook and need to future proof the lesuire battery with LifePo.
But would want the OEM readout to readout the correct voltage and ah left.

 

[G-A-R-Y]

Can I replace my varte 92 ah leisure battery for a 150 ah lithium in my grand california 600. If so can I swap over without any alterations to the present system. I would be very grateful for any information

Yes. I've just done this but it's not easy. Fitted a 160ah Roamer battery under bonnet. Just in the testing stages but last few days woke to 90% lithium. I'm planning to do a write up. Fitted the new Orion XS 50amp.

 

[Mr T]

All solved by using a small father/son outfit near Wantage, Off grid Power Solutions.
Replaced leisure with a 150Ahr LiFePO4 battery, replaced split charge relay with victron 50A DCDC charger and reprogrammed Votronic MTTP solar controller to Lithium. All work completed in a matter of hours. Battery has a bluetooth output to monitor charge/draw and level.
All works impressively well. Battery charge level around 60% on installation, by the time I had driven home (3 hours) the battery had soaked up the 60 or so Amps required to be fully charged. They did the whole job in a few hours and with no new holes drilled etc it would be possible to reinstall the old set up should you ever wish to do so! Not sure what the GC control panel will make of this but I will report back after our upcoming trip to France.
Photos below

View attachment 128239

View attachment 128240

Neat job, thanks for sharing. One thought is about the battery charger under the passenger seat, does this still charge the Leisure battery ok whilst on hookup? Not sure if it has the correct charging profile for lithium.

 

[leeb]

Sorry, wasn’t trying to be awkward. The KFG is the GC’s control unit that measures the battery usage. The small white box on the negative terminal of the battery is the shunt its uses to measure the current and hence Ah. As I understand the system the control panel % is communicated from the KFG and is based on the Ah remaining so it will read incorrectly unless the KFG knows it has a different capacity battery.

Ahaa...no recoding. I fully expected the battery page on the GC panel to give a false indication of charge remaining....but .....I have a blue tooth feed to the app on my smartphone.
The figures for current draw/charge and voltage tally exactly on the GC panel and the app. Charge remaining can be checked quickly on my phone.
Do you know if recoding is possible or practical?
I found a place near hamburg that advertises complete GC lithium electrical conversions (at a serious price!) but none in uk

 

[GordonH]

Ahaa...no recoding. I fully expected the battery page on the GC panel to give a false indication of charge remaining....but .....I have a blue tooth feed to the app on my smartphone.
The figures for current draw/charge and voltage tally exactly on the GC panel and the app. Charge remaining can be checked quickly on my phone.
Do you know if recoding is possible or practical?
I found a place near hamburg that advertises complete GC lithium electrical conversions (at a serious price!) but none in uk

The voltage on the control panel will still be accurate as will the current as they are direct measurements but the % State of Charge will be incorrect If you don’t somehow recode things as it is based on the calculation of average current drawn over time and battery Ah. The issue with that figure being incorrect is the GC will shut down a lot of the consumers when it ‘thinks’ you have dropped to.30% State of Charge based on the original 92Ah battery capacity, ie once you have drawn 64Ah.

 

[leeb]

Interesting...presume this unit must also integrate charge current too...otherwise how would it "know" SoC at any given instant?...We are about to start a road trip with some off grid days planned...I will watch performance closely and report back

 

[leeb]

Interesting...presume this unit must also integrate charge current too...otherwise how would it "know" SoC at any given instant?...We are about to start a r

The voltage on the control panel will still be accurate as will the current as they are direct measurements but the % State of Charge will be incorrect If you don’t somehow recode things as it is based on the calculation of average current drawn over time and battery Ah. The issue with that figure being incorrect is the GC will shut down a lot of the consumers when it ‘thinks’ you have dropped to.30% State of Charge based on the original 92Ah battery capacity, ie once you have drawn 64Ah.

View attachment 128260

oad trip with some off grid days planned...I will watch performance closel

The voltage on the control panel will still be accurate as will the current as they are direct measurements but the % State of Charge will be incorrect If you don’t somehow recode things as it is based on the calculation of average current drawn over time and battery Ah. The issue with that figure being incorrect is the GC will shut down a lot of the consumers when it ‘thinks’ you have dropped to.30% State of Charge based on the original 92Ah battery capacity, ie once you have drawn 64Ah.

View attachment 128260

As a side question...where have obtained all this detailed info on GC??....the rather useless handbook from vw is all I was given!!

 

[GordonH]

Interesting...presume this unit must also integrate charge current too...otherwise how would it "know" SoC at any given instant?...We are about to start a road trip with some off grid days planned...I will watch performance closely and report back

Yes, it’s all done in the KFG (or per VW documents J608 Special Function Unit) which is under the dash on the passenger side. You can identify it as it has the oft-mentioned ‘blue plug’. It measures the Ah using the realtime current derived from the current shunt on the battery (the white box ion the -ve in your picture with two small comms wires) to record the cumulative measure, current-time, Ah.The GCs control panel on the wetroom wall is mostly a display and touch screen, much of the measurement and logic is done by the KFG and communicated to the GC’s control panel on the internal LINBus. I did have a look via CarScanner & the OBD2 port to see if it was possible to change the ‘Battery Ah’ used by the GC for State-of-Charge % (which is the calculated used / rated Ah) but could only find one Ah field in the dataset and couldn’t tell if that was the starter or auxiliary battery. I’d imagine it is something that can be re-coded but you may need something more sophisticated than CarScanner, hopefully others more familiar with re-coding things will be able to advise.

 

[Black.Sheep.Cali]

Yes. I've just done this but it's not easy. Fitted a 160ah Roamer battery under bonnet. Just in the testing stages but last few days woke to 90% lithium. I'm planning to do a write up. Fitted the new Orion XS 50amp.

View attachment 128259

Would you have a photos of the battery installed? I was looking at this battery or relocating to an under seat battery

 

[G-A-R-Y]

I can confirm lithium stays at 13.2 so panel shows 100%. So NOTHING gets shut down. As a consequence water pressure is improved. Under seat battery charger still charges engine, drawing 55watts. And fuse removed for leisure battery, sixth fuse in under seat. Shunt is still very accurate. But time remaining all over the place just as before.

 

[Mr T]

I can confirm lithium stays at 13.2 so panel shows 100%. So NOTHING gets shut down. As a consequence water pressure is improved. Under seat battery charger still charges engine, drawing 55watts. And fuse removed for leisure battery, sixth fuse in under seat. Shunt is still very accurate. But time remaining all over the place just as before.

Good point, forgot that LiFePO4 batteries maintain a constant voltage during discharge.