I have read the stock BMS with a elm327 and a smartphone app, but the Arduino i have crudely patched into the hardware disables the onboard micro.
It should be easy to read the battery voltages and temp through the one of the CAN ports on there, i think there are two channels. Try looking for a ...

tidy setup, do you have contactor control on that board? I think this will need to be changed to reflect the number of modules and whether they are series / parallel

if((batteryVoltage > 300) && (compareVoltage > batteryVoltage) && (millis() - lastMillisContactor > 500))

I also found a thread ...