Slim battery needed, lithium or AGM

86scotty

Explorer
I'm looking for an unusual battery size to mount in the 'trunk' of a new Jeep JLU. I have 5.5" to work with, so a battery no wider than 5.5" laid on it's side will do. Pretty much everything I'm seeing is 6" or more and I really don't want to cut up the tray. I have found some much smaller batteries (<50ah) but hoping to find something in the 80-100 ah range.

I could mount two and am considering this but doing my homework first. Anyone know of a good, thin LifePO?

Oh, width and length of the space available are aplenty, I've got 12x12 I suppose just by eyeing it. I don't have access to the whole rectangular box because I'm mounting a compressor beside it.
 

highwest

Active member
What about DIY? I’ve never done it myself, but I’ve watched a few YouTubes, so I’m pretty much an expert. ;) It seems you could configure those cells to fit you space better than off the shelf options.
 

DiploStrat

Expedition Leader
Another vote for DIY with 280 Ah cells and Overkill Solar BMS. The carpentry is harder than the electrics. With shipping delays, pay the extra for US sourced cells.
 

hour

Observer
I can't think of any way you could fit a 280ah pack but I have a 100ah diy lifepo4 battery with cells that are 35x135(w)x200mm, so 5.3" wide. I stacked four of them laying down.

I'm confused about the space you actually have available though. 5.5"W x 12"L x 12"H?
 

86scotty

Explorer
I can't think of any way you could fit a 280ah pack but I have a 100ah diy lifepo4 battery with cells that are 35x135(w)x200mm, so 5.3" wide. I stacked four of them laying down.

I'm confused about the space you actually have available though. 5.5"W x 12"L x 12"H?
I think the 280ah advice above was just what they did, am in no way trying to get 280ah in the space I have. My goal is a 100ah setup or as close as I can get to it. This is a new Jeep. It has a tiny little 'trunk' under the rear deck where many people put things like air compressors, batteries, etc. Most of the battery setups I've seen there involve removing/altering the factory muffler which hangs just below and building a new/bigger/deeper box or using woefully small batteries. I don't want to do either. i just remeasured and have exactly 10"x15"x5.5" to work with, next to an air compressor which will go in the smaller space of 8x7.5x5.5. The hatch is not uniformly rectangle, it's smaller on one side.

I am thinking about two of these based on price and simplicity:


Still considering my options. I'd much rather have a solid 100ah than the 72 these will get me but they are cheap!

Here is an example of a 100ah setup I found on another forum but the guy hasn't responded to me yet asking what they are. Anyone know what cells those are or where to get them? So far I've only found them on Alibaba with an approximate delivery date of when I'll be dead.

Screen Shot 2021-11-24 at 9.37.10 AM.png
 

DiploStrat

Expedition Leader
I confess that I did not have a ruler or the exact dimensions of the 280 Ah cells at hand. They are very narrow.

They could easily be too big, but the point is that there are many prismatic cells at 50Ah, 100 Ah and beyond available. It is really a game of Tetris.

The concept is the same:

-- Assuming that you understand the concept of series vs. parallel vs. series/parallel, then it is really no harder to wire individual cells than it is to wire assembled batteries.

-- There are several BMS on the market that are very amateur friendly - Overkill Solar is one. Again, not that hard to protect your DIY battery.
 

86scotty

Explorer
I confess that I did not have a ruler or the exact dimensions of the 280 Ah cells at hand. They are very narrow.

They could easily be too big, but the point is that there are many prismatic cells at 50Ah, 100 Ah and beyond available. It is really a game of Tetris.

The concept is the same:

-- Assuming that you understand the concept of series vs. parallel vs. series/parallel, then it is really no harder to wire individual cells than it is to wire assembled batteries.

-- There are several BMS on the market that are very amateur friendly - Overkill Solar is one. Again, not that hard to protect your DIY battery.
No worries.

Yes, I'm very familiar with battery bank wiring and power systems including solar, I have just never built a lithium setup. I've been way too cheap on all of my previous rigs and just used SLA or AGM. The price of lithium has come down and It's time for me to get with the program.

I've been reading up on proper chargers/charging of lithium which was about my only learning curve. Thanks!
 

DiploStrat

Expedition Leader
In my case, my Lifelines were at the end of their life. I was able to cram 840 Ah into the space of 600 Ah of AGM. Total cost, including buying the tools, came out to well under $2500.

The carpentry was the hardest part.


EDITED TO ADD: This all assumes that you understand the different charging requirements of lithium iron and that you had adjusted your systems to match. Also, I KISS. Everything I did was bog standard and well within the examples on the DIY Solar forum, etc.

So far, the results have been excellent. But a wonky connection to one of the BMS gave me fits until I was able to isolate and correct the problem.
 
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