Making the change from lead acid to lithium - a thread with pictures

[Googlebot]

Thanks autorouter, that’s where I got confused then. I knew there was another feed for the hab batteries, wasn’t sure if you could do without the one on the back.

 

[growly_bear]

I agree with what's already been said. The hab connection at the back of the EBL (Wohnraum Batterie) is essential for supplying all the hab loads (lights, water pump, fridge/heater controls etc) as well as a possible path for the solar and aux battery charger.

The cab connection (Starter Batterie) is redundant - it only feeds the split charge relay, which will of course not be required if you are fitting a B2B. You can pull the 50A fuse to disable it, or if you want you can disconnect the wire from the EBL and use it for the B2B if it's thick enough. The split charge relay will still click on and off, but won't do anything because there's no connection to the starter battery.

The 20A feed from the starter battery to the EBL comes in on Pin1 of the 5-way connector, and provides all the other starter battery functions: fridge 12V heater element power, starter battery trickle charging, and starter battery voltage sensing.

Note there is a thin voltage sense wire on the hab battery, with a 2A fuse next to the main 50A fuse, and a separate thin negative. These allow accurate battery voltage measurement without the voltage drop that occurs along the main power wires. Be sure to keep these wires, the EBL shuts off it it can't see voltage along them

Thank you autorouter for your confirmation. The last paragraph was something I've never encountered. My VW days didn't have this sophistication!

 

[JockandRita]

If anyone is considering lithium along the lines as described in this thread, but daunted by the cost and complexity - and you're not doing it for the weight saving - a good alternative is lead carbon gel. As long as you have Gel settings on your charging devices (and it physically fits) these are a 'drop in' solution that increase your usable Ah (over a standard lead acid).

As an example I installed a 110Ah one (in my 2002 Hymer B584) that gives 88 usable Ah. £190 and gets about 750 cycles (if discharged that much. Much more at a lower discharge). It's a bit higher than a standard 100Ah and I put it under the seat. I cut the plywood base it sits on so it actually sits on the floor and used the mate bolts rather than post terminals so it would fit.

You searched for lead carbon gel - Alpha Batteries

www.alpha-batteries.co.uk

Without wishing to hijack the OPs thread, how long do the Lead Carbon Gels take to recharge?
My moving away from Gels to FLA, was due to the horrendously long time it took for the 4 x 80A Gels to recharge, albeit thay were well used anyway.

Cheers,

Jock.

 

[wfdTamar]

Well, yes 4 x 80Ah gels (or any non lithium) batteries will take a long time to charge (does depend what you're charging with and at what rate). The 110Ah LCG can take 20 Amps, so around 4.5 hours if discharged down to 20%.

 

[JockandRita]

Well, yes 4 x 80Ah gels (or any non lithium) batteries will take a long time to charge (does depend what you're charging with and at what rate). The 110Ah LCG can take 20 Amps, so around 4.5 hours if discharged down to 20%.

So, more or less the same charging time as normal Gels............which is significantly more than FLA batteries, and obviously, drastically more than LiFePO4.

Cheers,

Jock.

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[wfdTamar]

I don't think you'd want to charge FLA any faster than that either.

 

[wfdTamar]

Here's another option. What I did when my fridge died and I installed a 100Ah lithium with its own 300 watts of solar and a 30A B2B charger and an 800VA inverter to run the 240 volt fridge (which BTW, is a great way to do a fridge).

This is completely separate from the original leisure system (which now uses a 110Ah lead carbon gel battery and 200 watts solar).

So I have dual leisure systems and can run optional stuff (chargers, 32" TV) off either.

If redoing the lot though I'd probably go for one system with at least 200Ah of batteries so I could use a decent sized inverter to run more power hungry devices (maybe air fryer).

On my Tasmanian Hymer I've installed a 626Ah DIY lithium battery (with 710 watts solar and a small B2B).

 

[growly_bear]

Problem with that one is when it sees a solar input the B2B output reduces to 25amp. You can get arund with a switch on the solar input or a relay switched by the D+.

Lenny HB I was reading the install manual (G4 version). It states that the nominal input from solar has to be 7A for solar to charge (engine running). Less than this, and it switches of solar charging in favour of 50A alternator charging. The best bit, is that this 7A figure is adjustable to zero! I'll still need an isolator between the panels and the controller so as not to charge from solar when not using for a while (lithium).

 

[Lenny HB]

Lenny HB I was reading the install manual (G4 version). It states that the nominal input from solar has to be 7A for solar to charge (engine running). Less than this, and it switches of solar charging in favour of 50A alternator charging. The best bit, is that this 7A figure is adjustable to zero! I'll still need an isolator between the panels and the controller so as not to charge from solar when not using for a while (lithium).

Sounds like they have updated it.

 

[growly_bear]

I've ordered one and their 2000w inverter. Also Fogstar 280ah cells and BMS. I'll start separate thread with my install. I'm sure I'll have loads of questions which will help others too.

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[Baggins@chill]

Good morning all, apologies as I don’t have anything technical to add but just wanted to say that it is great to see people helping each other out, and good luck with the upgrade. BZ