Availability of a 40 or 50aH LiFePo4 Lithium Battery with built-in BMS suitable for motorhomes / campervans?

[Barti Ddu]

The recent posts regarding upgrades to LiFePo4 lithium from standard lead acid batteries, and whether or not they can be a straight drop in replacement has got me thinking.

I'm a low power user. Only have a 72aH wet lead battery and a weedy fixed voltage (13.8v) Sargent charging system. Even so, we rarely use sites or EHU, and a 100w solar panel and Victron controller has meant we've never had an issue on aires or wild camping. On the basis that I never try to go below 50% depth of discharge, my usable capacity is only around 36aH.

My current usage is therefore such that Lithium is probably overkill for my needs and I'm generally happy with the standard lead battery setup. However, the standard lead battery takes up valuable storage space under a rear locker in my PVC, especially in its vented plastic box. It makes chairs and tables awkward to fit in the locker.

On the basis of my low power requirements, a 40 or 50aH LiFePo4 lithium battery would provide greater usable capacity than my current 72aH wet lead, and take up less room and not require a dedicated battery box. A quick search online shows that such a thing exists as a niche product for golf carts, etc., but there is no mention of a BMS. Does such a thing as a 40 or 50aH with a built-in BMS that is suitable for motorhome/ campervans exist? I would think that a market for such a product would be potentially significant, particularly for the VW T4 / T5 market.

 

[Itsmcb]

Have a word with RogerIvy

 

[Guigsy]

Lithium batteries don't just gain capacity as they get bigger, they also cope with bigger currents for both charging and discharging. So a pint sized battery might only have a 25amp capacity.

 

[Swifter]

Yes they are widely available.

 

[Barti Ddu]

Lithium batteries don't just gain capacity as they get bigger, they also cope with bigger currents for both charging and discharging. So a pint sized battery might only have a 25amp capacity.

25amp charging is more than the Sargent charging system and Victron solar controller can produce combined, so shouldn't be a problem.

Similarly, our usage is modest. Laptops, phones, lights, water pump, blown air heating all on 12v. No requirement for an inverter, so 25amp max discharge would be more than we would ever need.

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[Barti Ddu]

Yes they are widely available.

I've now found found a Renolgy 50aH one that appears to have a BMS. Any others?

Anyone go out any practical experience of low capacity lithium in a motorhome/ campervan? RogerIvy ?

Thanks.

 

[Cush]

Yup may find that your sargent charger (like mine) does not go high enough to fully charge the lithium And may need replaced

 

[bigtwin]

Life Batteries do a 50Ah battery for £200.

Life Batteries 50Ah Battery

Ian

 

[cmcardle75]

Almost all 50Ah LifePO4s will have a BMS. One without would be a bit of a niche item for incorporating into other systems.

LiFePO4 12V 50Ah Lithium Iron Phosphate Battery | ECO-WORTHY

ECO-WORTHY LiFePO4 12V Lithium Iron Phosphate Battery has twice the power, half the weight, and lasts 8 times longer than a sealed lead acid battery, no maintenance, extremely safe and very low toxicity for environment. Our line of LiFePO4 offer a solution to demanding applications that require...

uk.eco-worthy.com

Here's one for £161.

 

[Jimbohorlicks]

One of the fun ladies has a 60 ah for sale
Wendo55

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[pappajohn]

A 50ah lithium discharged to 20% will give you a usable 40 amps.
You 72ah lead acid discharged to 50% will give you 36amps

For an extra 4amps the cost of a lithium battery simply isn't worth it plus you'll need a new lithium capable charger and unless the solar reg has a lithium profile that needs replacing as well.

Financially not worth the trouble.

 

[RogerIvy]

TBH we’ve not seriously considered anything less than 100AH, for two reasons:
1. The 100AH is a pretty small battery, usually easily fitting into the place where the old battery was. It’s also really light (12kg).
2. The manufacturing (Labour) costs of a 100AH are the same as a 300AH, so it’s difficult to get much lower in price than a 100AH.

But I understand your question is around size, with a view to moving the battery location. As others have mentioned, there are some batteries less than 100AH
We‘ve put together loads of custom batteries to fit into special places. That could be an option. We prefer building those with a JK BMS where possible because it’s such a great BMS. There are others that are really good (such as JBD). Many of the custom batteries are for small campers and 4x4’s, and in such cases they have very low power requirements.

 

[cmcardle75]

A 50ah lithium discharged to 20% will give you a usable 40 amps.
You 72ah lead acid discharged to 50% will give you 36amps

For an extra 4amps the cost of a lithium battery simply isn't worth it plus you'll need a new lithium capable charger and unless the solar reg has a lithium profile that needs replacing as well.

Financially not worth the trouble.

There are many advantages to the Lithium. Not only is it smaller and lighter (a critical element here as the original 100Ah lead battery is too large), they are far more efficient on a round cycle basis and don't self discharge for years. A lead acid needs topping up over winter and wastes a significant amount of your solar when charging. Also, whilst you get extra longevity from a LiFePO4 by not over-discharging or over-charging, they aren't anywhere near as sensitive as lead batteries to such, so you can comfortably use almost their entire output occasionally for emergencies. (The BMS should cut out before any gross damage).

 

[Barti Ddu]

Thanks for all the comments and links to various batteries.

The 50aH Eco-Worthy lithium linked to by cmcardle75 at £161 would only be approximately £60 to £65 more than a replacement 72aH lead acid, and give more usable capacity, smaller footprint, lower weight, and have significantly more life-cycles / longevity.

Interesting.....

So would my Victron solar controller and 100w panel be able to do most / all of the charging? It's got a lithium profile. As we don't use EHU very often the basic Sargent charger could be switched off. The van has a standard (non-smart) alternator and split charger so even if not as efficient as a B2B charger, this would presumably provide some useful charging when we are on the move in the winter months when the solar might struggle on it's own.

If, so, it could realistically be a drop in replacement in my particular scenario and limited needs.

 

[cmcardle75]

Thanks for all the comments and links to various batteries.

The 50aH Eco-Worthy lithium linked to by cmcardle75 at £161 would only be approximately £60 to £65 more than a replacement 72aH lead acid, and give more usable capacity, smaller footprint, lower weight, and have significantly more life-cycles / longevity.

Interesting.....

So would my Victron solar controller and 100w panel be able to do most / all of the charging? It's got a lithium profile. As we don't use EHU very often the basic Sargent charger could be switched off. The van has a standard (non-smart) alternator and split charger so even if not as efficient as a B2B charger, this would presumably provide some useful charging when we are on the move in the winter months when the solar might struggle on it's own.

If, so, it could realistically be a drop in replacement in my particular scenario and limited needs.

In summer conditions using it only for water pumping, lighting, phone charging and basic entertainment, a 100W panel on the roof, so it was effective driving, parked and camped, would likely be all you needed, regardless of EHU. A split charger only really works at low charge (especially for modern vehicles), but might be useful if you drive a lot. If you upgraded anything, I would suggest this aspect, to a decent 20A+ B2B.

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[cmcardle75]

In summer conditions using it only for water pumping, lighting, phone charging and basic entertainment, a 100W panel on the roof, so it was effective driving, parked and camped, would likely be all you needed, regardless of EHU. A split charger only really works at low charge (especially for modern vehicles), but might be useful if you drive a lot. If you upgraded anything, I would suggest this aspect, to a decent 20A+ B2B.

I've also found that having a decent mains charger is key. Sometimes poor weather, or a shortened driving itinery has detented the solar/B2B opportunities that you had relied on. However, if you've got a decent mains charger, you can just go somewhere with enough mains amps and charge the whole lot, which might be enough for several days, depending on your setup. Basically it is a good idea to make sure you have enough mains charging capacity to be able to refill to 100% on just your few overnight hours. This is probably more important to those with smaller batteries (and easier to achieve, luckily).