Example code to read "monitoring 2" message from BMS from Dong Guan Shi Bestway Technology Co. Ltd., based on BMS Serial Communication Protocol version A5 dated 2018-12-10.
Requires an arduino with Serial3, such as the Arduino MEGA or Arduino DUE. The Serial3 interface is assumed to be connected to a RS232 to RS485 converter, with DE and RE connected to pin 45 on the arduino, and DI connected to pin 16 and R0 to pin 17. The serial print of voltage and current was added in post haste, and hence can be removed if required.
Meant to be run on a computer connected with a USB to RS485 converter on /dev/ttyUSB0 and the BMS connected with to said converter via the required A, B, and GND connections. Requires Python3 and pySerial to be installed. Reads the BMS "monitoring 2" message once before exiting.