LiFePO batteries..

[DamperMan]

I was thinking of replacing the massive but fairly limited leisure battery in my campervan for a Lithium ion battery.. But the more I looked into it the more complex it became… currently the leisure charged off the alternator when the engine runs.. also from the solar. Also a Zigg 12 10a supply from mains when in site…    But it appears all of these are bad news and I’d need to use a DC - DC charger, and a load more complication..   Yet we fit them as a direct replacement as a battery on our cars and allow them to charge of a 45a alternator..   

 

 

[evosteve]

1 hour ago, DamperMan said:

I was thinking of replacing the massive but fairly limited leisure battery in my campervan for a Lithium ion battery.. But the more I looked into it the more complex it became… currently the leisure charged off the alternator when the engine runs.. also from the solar. Also a Zigg 12 10a supply from mains when in site…    But it appears all of these are bad news and I’d need to use a DC - DC charger, and a load more complication..   Yet we fit them as a direct replacement as a battery on our cars and allow them to charge of a 45a alternator..   

 

 

I wouldn't use one myself, but understand why some do if chasing weight saving.

[Flying Carrot Steve]

 

17 minutes ago, evosteve said:

I wouldn't use one myself, but understand why some do if chasing weight saving.

 

 

Any particular reason?

 

I have a JWM one in my Carrot, it's been brilliant so far, arguably the best battery I've ever had in any of my kits. Perhaps need a full season to assess fully but atm it looks like an excellent move. Absolutely flies the engine round and starts more easily than it ever has before! 

[evosteve]

Just a personal choice, I like a SLB with a high purity lead electrodes. Never had a problem with them.

[Mole]

8 hours ago, DamperMan said:

I was thinking of replacing the massive but fairly limited leisure battery in my campervan for a Lithium ion battery.. But the more I looked into it the more complex it became… currently the leisure charged off the alternator when the engine runs.. also from the solar. Also a Zigg 12 10a supply from mains when in site…    But it appears all of these are bad news and I’d need to use a DC - DC charger, and a load more complication..   Yet we fit them as a direct replacement as a battery on our cars and allow them to charge of a 45a alternator..   

 

 

Might be having a word with JWM to see what they think...

[Andrzej]

Here is what ChatGPT said  :

 

 

replacing a lead-acid (or gel/AGM) leisure battery with a lithium (LiFePO₄) battery in a campervan is more complex than it first appears. In regular cars, the switch seems straightforward because their systems are simpler and don't typically have multiple charging sources like a campervan does.

Here's why you need to be careful when upgrading:

Alternator Charging:
Older alternators try to charge lithium batteries like they would charge lead-acid ones. This can be inefficient or even harmful to both the alternator and the battery. Lithium batteries require a consistent charging voltage (typically ~14.4V). That's why a DC-DC charger is recommended — it regulates and optimizes the voltage coming from the alternator specifically for lithium.

Solar Charge Controller:
Your current solar charge controller may be set up for AGM or gel batteries. Lithium batteries need a different charging profile. You’ll need to check whether your controller has a LiFePO₄ charging mode — if not, it may need upgrading.

Zigg 12 (Mains Charger):
This unit was likely designed with lead-acid chemistry in mind as well. It might not reach the right final voltage or provide the correct charging behavior for lithium. You’ll want to check the specs carefully — a dedicated LiFePO₄-compatible 230V charger might be needed.

BMS (Battery Management System):
Most lithium batteries have a built-in BMS, which protects against overcharging, deep discharge, etc. However, this doesn’t replace proper charging hardware — it’s a safety net, not a substitute for correct voltages and profiles.

In summary:

Yes, it's totally possible — but you do need to pair the lithium battery with the right components: especially a DC-DC charger and a suitable solar controller. If everything is set up correctly, lithium is a great upgrade: lighter, more usable capacity, faster charging, and longer lifespan.

Would you like help selecting specific gear or checking if your current setup supports lithium?

I can show you how a DC-DC charger works, the key differences in lithium charging profiles, or whether your Zigg 12 is compatible with LiFePO₄.

[Andrzej]

I started to "study" this topic also. Foud that LiFePO4 have always much lower PEAK discharge current (typicaly 40-50-60 A  with 20A 12v battery). Then BMS shoud cut current . 

 

Acid lead batteries are better in this . I am going to experiment , today got my first LiFePO4, will try to start differnt cars with it, and try if will be albe to move electric reverse in BEC kitkar...