I try to keep my LiPo packs as simple as possible with high capacity cells such as 4S 20A and 6S 20A packs. When my packs come off at 62V fresh off the charger (4S @ 3.9V/cell), the regen does not work as over voltage protection is set at 63V since it will not even run with the default setting.
(2) 4S + 6S packs gives me 14S 20A which has been a great voltage to run the MP5 at. I usually set the under voltage alarm via cheaper cell alarms ($4/ea) that have a simple LED and pretty loud alarm allowing one to set the alarm at the cell voltage they want. I like the Cell Log as it can do a lot more and even handle 8S packs, but I only have one.
I also use an RC balance charger to reset and condition my packs to be in good health. I have put serial numbers on each pack and created a small database to log each use. In addition, I often carry a bulk 6A 14S charger for lithium ion/poly batteries as its small and effective for getting my pack up to around 57.4V. These batteries are rated to charge up to 4.2V/cell, but for each 0.1V you lower at charge, it doubles the cycle life of the battery. Of course there is a point where the battery serves no utility, but I tend to charge from 3.9 to 4.1V/cell depending on what my immediate needs are.
Why no
BMS? I don't like to charge to the maximum voltage per cell. I like to be able to monitor each cell--they don't get out of balance as long as I don't overdischarge them. I have had previous experience with a FEW battery packs where the
BMS failed or did not perform to my liking (cells not balanced actively, discharge rate too low). I have even been stranded due to a overheated
BMS in lockout mode. My laptop batteries that have failed often revealed mostly a good battery with a single bad cell.
I still have two packs with newer 18650 cells that have a
BMS. I allow friends and family members to use them as they are simple to use (until they catch fire).
