Requirements
Take in Passthrough 18 V - 55 V (6S lower voltage to 12S upper voltage )
Measure current through hall effect current sensing (without a shunt resistor to minimize losses)
Measures voltage with an ADC
I2C or UART interface
Preference toward I2C, but just pick one of them
XT60 connector for input power and output power
Implementation
5 V or 12 V power input on the data header
Power comes in from a separate source
May need an LDO from 5Vor12V to whatever voltage ADC requires