I am building a 14s7p 21700 battery of 50s cells and need a BMS for charging. For discharge I am just connecting directly and use a 150A fuse plus limits in the VESC.
I dont have a charger yet but maybe I’ll go for a 20A.
Any suggestions for BMS?
I’ve been using the JKBMS B1A20S15P so far and I’m quite pleased… all cells balanced within 0.005V and 1A balancing current.
Using it for charge and discharge, everything can be customized on the Bluetooth app.
A somewhat more complex alternative is to implement a cell balancer in the battery pack and let the charger handle the CC/CV part. At this point the charger will be a simple AC/DC converter that has the constant current/constant voltage functions, or as in my case, a 24V power supply cascaded to a DC/DC converter that delivers a constant voltage and current to the battery pack. The disadvantage is that you lose safety features like temperature monitoring, overcurrent or overvoltage protection, but if you know what you’re doing in my opinion they’re not that critical anyway. The main advantages are light weight, simplicity, and the ability to choose components to suit your needs. Other significant advantages are the cost being around 1/3 or less and the ability to replace individual components if they break.