Now that I am addicted to my electric skateboard with the nice performance of the VESC I feel that the only thing missing is a decent and competent BMS for a wide configuration of cells. Therefore I would like to start a long term project which I will document here, both to keep myself motivated + maybe implement some great ideas that arise in this topic. I think and hope that this forum is the right place for this new hobby project , feel free to point me to a problem you think I didn’t adres that is a bottleneck for the current available BMS’s.
Please note that my goal is not to make a cheap or affordable BMS, my goal is to make the most competent BMS for e-skateboard applications.
It will have the following features straight away: *Soft power switch input with LED on / off / charge indicator. *Charge input -> switched (high side) -> to charger input (to disable charger if a cell reaches the max voltage) *Discharge input -> switched (high side)-> to motor controller / VESC (to disable the load when a cell reaches the min voltage) *CAN bus interface for cell voltage monitoring and charger detection, status monitoring + more with future updates (like state of charge / state of health). *Charge current sensing (future capacity measurement) *Discharge current sensing (future capacity measurement) *Pre charge for high capacitive load (with short detection, in case the motor controller is shorted / dead / wrong polarity) *USB interface for serial communication and flashing (no need for a programmer -> HW serial bootloader is used)
Future features: *mAh / Wh counting + soc + soh calculation. *option to connect a cheap oled display for soc / soh display *firmware update over can (trough VESC maby?) *Chrome based configuration interface (+ firmware upgrades)
So far in my pre investigation I think I will be going with the following chipset: BQ76200 For high side N-FET switching + precharging LTC6803-4 Battery stack monitor CP2104 USB serial interface STM32F303K8 uC with HW floatingpoint LM5165 Power supply with 744043151 ISO1050 CAN Transceiver isolated BF1 Series fuse
Tracked in github (still in a very early stage):
Schematic can be found here (UPDATED).
Thanks for your time :).