Originally Posted by
E.A. Webb
Are you risking a fire?
Low voltage is monitored via low voltage alarm with constant voltage displayed for each bank.
Preliminary charges - discharges are monitored, then each bank rearranged for equal capacity.
Then, typically, I charge each bank to about 4.1V per cell.
This is to prolong lifespan, some estimate double the number of cycles.
Even if 1 cell totally fails, on a 10s8p 36V pack, maximum voltage on the damaged bank is less than the rated 4.2V.
So ... barring traumatic or dramatic damage or failure, there is an extremely slight chance of any possible overvoltage reaching, even near to, danger level.
I've built 4 Li-ion packs and 2 LiPo packs, and run hundreds and hundreds, maybe 1000 recharges. (37V and 25.9V builds)
Nearly 15,000 recycled Li miles over the past 5 years.
Right now I am rebuilding my 2008 builds. (2 - 37V and 1 - 25.9V)
Separation and re-evaluating all cells individually.
Recharge
Voltage bleed down test
Capacity test
Reassembly
Note - I did use a PCB (BMS), to begin with, but quickly went to monitored bulk charging. Balance circuitry was minimally effective and only worked at full 4.2V and only if cells were closely matched already. I was disgusted at the cost and lack of effectiveness. The last straw was the balance circuit did absolutely nothing when I switched to a less damaging, life preserving, 4.10V per cell.