Bottom Balance Precision?


New Member
Hi there!

I've recently taken my home-built EV off of the road and now I have 45 CALB 130Ah cells to work with. Actually, let's call it more like 43 cells since one had died completely and another was sitting down around 2.9 VDC when I first checked it after beign in storage for 90 days. Since then, I've slowly brought it back up to 3.3 VDC using a Venom LiPo charger from my R/C kit. All of the others were still at 3.29VDC.

I am building a series of 12VDC batteries for my camper. Planning to have 300+ Ah of storage in the camper with at least 300 watts of solar, controlled by Victron equipment.

My question: when bottom balancing, what degree of balance precision to you use? I've balanced 4 batteries (4s) so far and I've been working to get them with 10 mV of each other. Just wondering if that is necessary?

I'm being VERY conservative with these cells. Meaning I'm limiting the bottom voltage of the 4s batteries to 12VDC and a top voltage of 14.4 VDC. While in the EV, I never let them go below 3.0 VDC and NEVER above 3.6 VDC. I had a theoretical 55 mile range but never went more than 25 without a recharge.

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