GC600 Lithium upgrade

[TCC Services]

Hi

Has anyone fitted a lithium battery in the engine compartment to replace the original AGM plus fitted a lithium in the garage area to get extra power ?

Solbian Solar can supply me the solar kit. Ideally I wanted to fit a dummy battery in the engine bay and single lithium in the garage, Tried Car Electrik but they haven't replied to me. Has anyone manage to source one ?

 

[AndrewCook680]

Hi have a search on this forum and also recent discussions on this in last few weeks.
Some folks have discussed putting lithium battery in engine bay
Also see UK grand California Facebook group

Cheers
Andrew

 

[DMC]

Hi

Has anyone fitted a lithium battery in the engine compartment to replace the original AGM plus fitted a lithium in the garage area to get extra power ?

Solbian Solar can supply me the solar kit. Ideally I wanted to fit a dummy battery in the engine bay and single lithium in the garage, Tried Car Electrik but they haven't replied to me. Has anyone manage to source one ?

It’s worth giving Car Electric a call. They have English speakers and their product is well worth considering. We had 2 x 150 lithium batteries and a Victron inverter fitted by them in March 2025 and it has been brilliant.

 

[Nickg60]

Fogstar do a drop in lithium replacement for the lb, and you can code the on board electrics to charge correctly while driving but the 240v charging system will be incorrect and the camper side of the electrics won't report correctly.

Dummy battery has the same issue.

I feel the best solution (which is the one I went for) is put as much power as you require in the rear garage with lithium and allow the main lb to stay as it is. This keeps the original system intact. I changed the rear red switch to a 0-1-2 switch so I can feed the van from either the rear lithium or original AGM, DC/DC charger from the same technical cabinet feed and a multiplus to run the 240v. 8kw of lithium in the back runs the van happily for a good 8-10 days at standstill with a second fridge running, starlink and charging devices, on a regular week of moving around never drops below 50% even using the air fryer twice a day. Everything is contained in the rear cabinet and in the box underneath the consumer unit.

If you want to box in the dc dc charger where the leisure battery is there is a detailed thread over on caliboard.de and a suitable battery 'box' on there.

Solar is my next job, and I was looking at the Solbian OEM kit so i'm intrigued as to how you get on with that?

 

[maxtorque]

I have 5kWh of Lithium in the rear offside cupboard where the gas bottles used to live, and i've left the std 12v leisure battery alone.

My lithium runs at 24v nominal to allow for a greater 240V power output without huge cables. (if i did the install now in 2026, i'd go 48v!!). What i have is some basic node red control code that keeps an eye on the voltage of the OE 12v leisure battery voltage, and can turn on a trickle charger if necessary to dump energy down from the 24v lithium into the 12v leisure system.

This is needed because ime, the 12v system cannot keep the fridge running when the vehicle is not being driven regularily and hence not getting charged from the alternator. ( recent exploration of the fridge system actually shows that it's very easy to swap the fridge over to the 24v supply as the fridge compressor is able to run natively on either 12v or 24v....)

I use a voltage setpoint of 12.5v, allowing the engine alternator to fully charge the 12v battery as normal, and for the OE roof mounted 100w solar panel to also charge it when it's sunny enough. However, when the voltage falls to less than 12.5v for more than 5min, the 'downcharger' is enabled and pushes around 100w (8A 12.5v) into the 12v leisure battery to prevent it from excess discharge.

I've done this for a few reasons

1) don't need to touch the std smart alternator system

2) lithium batteries in hot underbonnet environments are a really bad idea (short life, low charge acceptance etc)

3) the std 12v leisure battery holds so little energy it's not really worth the effort of replacing (approx 45Ah 12.5v is just 560Wh, vs the 5100Wh (200Ah 25.5v) stored in the lithium. and it acts as a nice "damper" for the high current DC/DC that charges the 24v lithium, because the std smart alternator is not a reliable constant energy source. Because the OE 12v Lead acid is very happy to accept high surge currents in charge and discharge using this battery as a buffer between your alternator and a high voltage sub-system is a really good idea, it means you can maximise your alternator output on short drives

4) as mentioned, i knew i needed more than a nominal 12v for my primary energy storage as i wanted at least 3kW of inverter, and i did not want to have to run huge cables everywhere to achieve that (we now cook on a 2.4kW dual induction hob installed in the kitched unit in place of the std gas hob), so there was little benefit in trying to use the OE 12v battery to store any meaningful amount of energy