Charger Delta Electronics ESR-48/40A E Voltage and Current Adjustments
TL;DR

https://www.batteryspace.com/prod-specs/6411-Canbus-v4.pdf

The BMS uses the following link level spec.
1) bitrate; 500Kbps
2) Packet Rate; 50milliseconds
3) packet; standard format
4) ID; 04D


(just from a web search not 1st hand knowing)

Make DIY project  You can search for buy options.