"As to BMS systems as far as I know they do not monitor each cell. Rather they monitor each battery, which is comprised of many cells. So in every case you are the BMS in the end. " The batteries you are using are considered large prismatic cells and the BMS systems will monitor every cell. Something like a Tesla with thousands of cells is a different story. I use one called "Mini BMS". This system warns me with a loud buzzer if any cell gets below 2.5V . It has saved me twice. My main gauge is an amp hr counter but twice it has gotten out of sync and I thought I had more charge than I did. With out the warning buzzer I would have kept driving and possibly damaged a cell. If you bottom balance you stand less of a chance of doing damage if you run the pack down too far. Anyway, in any pack there will be one cell that gets to the cliff first. (unless they are perfectly bottom balanced). I decided that I want to know when that happens. kimball |