DIY batteries a lot cheaper?

thegoogler

Solar Enthusiast
Joined
Apr 15, 2021
Messages
96
So, I’m seriously considering building a DIY battery. Watched Will build a few on YouTube and it looks like fun, and a good learning experience. A while back Will built a 12 volt, 200 amp hour battery with Fortune cells and a Overkill BMS. The 8 cells cost about $960 ($120 each), and the BMS another $142, which totals $1102. The Overkill BMS also has Bluetooth and a great app. Then I saw him review an SOK 12 volt, 206 amp hour battery - which he highly recommended - at a cost of $1029. In that review video he states “you can make your own battery for much cheaper”. I’ve also seen many other YouTube videos where this is stated as well. So, I’m a little confused, and am probably missing something very obvious. Am I comparing apples to apples? Can someone please shed some light on this subject. Thanks!!
I built a 12V, 270-280Ah battery for about $650 once all the parts were accounted for. If I'd tried to build ~200Ah it probably would've been $550, give or take. So about half the cost of the SOK (though IIRC the BattleBorn batteries I was originally comparing pricing to were around $900 for 100Ah).

The larger the battery you build though, the more savings you'll get per Ah. Basically the BMS, wiring, terminals, fuse, compression method (rods/nuts, foam mat, or tape), battery case, etc are all a fixed cost... about $200. The cells are the only thing that really varies. So there's less savings (per Ah) if you build a 100Ah battery than if you build a 300Ah one, since you spread the fixed costs across the larger battery. You can see my parts list here:


DIY will probably be cheaper. If you have to buy all the tools needed it won't be as great a bargain. The $650 above doesn't account for the bench charger I bought, for instance, but I will use that for other projects so I'm ignoring the tool costs.
 

Just John

Photon Sorcerer
Joined
Aug 15, 2020
Messages
2,381
The 280ah cells are the best value, with some trade offs. There have been a lot of substandard cells on the chinese Ali sites recently, I believe also Amazon. The Luyuan 280ah cells and the JBD BMS would be my comparison items - check out in more depth and others on this forum.

I've done extensive testing of various models of Daly and JBD BMSs, and JBD is definitely what I would recommend. I did have to calibrate mine to get things to work as well as they should. Daly was worse.

While quality cells direct from china have gotten more expensive, the pre-made products available in the US have gotten cheaper. Ampere Time and Chins would be the one's I'd look at, in addition to the SOK.

Basically if 100AH meets your needs, you should go with one of the cheap Amazon ones. The Zooms Will reviewed are a very good price, and I noticed others (Chins) have dropped to match them. When you get to 200AH, it's cheaper to build your own 280AH battery, and get nice extras like Bluetooth monitoring, extra capacity, and the ability to "service" them if they develop a problem..

Another thing about the quality products is a lot of the fine tuning stuff that's also detailed on this site is not needed. Those techniques, and the equipment to do it, can make those bargain cells work but its more than I wanted to take on.

This is true, pretty much for 100AH 12v batteries, it's cheaper and much easier to purchase a good one Will has reviewed on Amazon.
 
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