200ah lithium. One battery or two?

PatriotX

New member
Hi folks,

I’m building a small-ish off-road trailer [~5x7’] for the next step in this overland adventure we call life.

After auditing my power needs [thanks kill-a-watt] it looks like 200ah of lithium would be enough for my current usage.

I do winter camp, so self-heated batteries are on the menu. Is there any overarching reason to go with a single 200ah cell over two 100ah batteries wired in parallel ?

Pricing isn’t much different for 2 vs 1. I could run a single battery if one is damaged or needed elsewhere.

All input welcome, thanks!
 

JaSAn

Well-known member
Redundancy
Easier to muscle two 40lb batteries vs one 80 lb battery, especially if they are in an awkward place.
 

DirtWhiskey

Western Dirt Rat
I agree the you above. Also most heated Bluetooth lifepo4 have a lower power output BMS. A lot of the 200ah BMS have the same output as 100ah. What that means is that by going with two 100 amp hour batteries you'll end up with twice the output capability if you ever want to do larger loads like inverters.

I got the heated Bluetooth SOK batteries and I wouldn't be happier. I personally think they can't be beat for the price. Metal case with a removable lid so its serviceable. High quality cells too.
 

CalgaryMcLean

Active member
If space is a concern, something like the SOK 206 A-hr battery packs a lot of storage into a compact space.

But, redundancy and ease of replacement are nice.
Many of the most compact batteries are not standard automotive sizes.

I have seen some builds where the battery fits perfectly and tightly in its spot.
Problem is, what happens if the battery needs to be replaced?
The replacement might not be exactly the same size. Could be a different manufacturer, or just a manufacturing change.

I am using a pair of 100 A-hr batteries and sized the storage location to fit generic group 31 batteries.
My batteries are nominally group 31 size but are slightly smaller. Use some spacers to keep the batteries in place.

If needed, the batteries could be replaced on the road with a readily available lead acid group 31.

The lithiums should last for years, but I am not relying on that.
 

PatriotX

New member
Great discussion, thanks.

The insulated battery box hasn’t been built yet, but oversizing it for an appropriate lead-acid replacement in the field was one of the criteria. I’m hoping this latitude would cover the potential differences in Lithium batteries as well, within the same form-factor.

The BMS issue is a valid one as well, so thanks for that.

I’ve reached out to a couple of the manufacturers that rated highly on some video tear downs. I’ll report back
 

01tundra

Explorer
Most 100ah LiFePO4 batteries have a maximum discharge rate of 100 amps continuous due to the BMS, so two 100ah in parallel allows a max current of 200A, which can come into play if you ever plan to add a decent size inverter.

Most 200ah batteries also have a max current rating of 100A, so the 200ah battery has less capability there.

And then as mentions, there's also redundancy with the two 100ah.
 

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