Is there a set of communication protocols to communicate with BMS?

ArduCopter
1

fWhat data does the flight controller need to receive from the smart battery? There is no such document or information? Thanks in advance

2

Take a look at the BatMon protocol implementation

3

Here is the I2C smbus protocol document that is supported.

http://sbs-forum.org/specs/sbdat110.pdf

You may want to look at the smartbatt_info message in mavlink.
https://mavlink.io/en/messages/common.html#SMART_BATTERY_INFO

PR for that here: https://github.com/ArduPilot/ardupilot/pull/16167

There are CAN smart battery types as well defined in battmon. And PRs in regards to CAN smartbatts here,