Connect different Battery to the Mainboard

Hey guys,
this might be a stupid question, but has anyone tried connecting a different battery pack to the mainboard? Would it theoretically be possible to connect a 4S LiIon pack, if you want to use the mainboard in a different project?
Is the pinout and protocol for the battery known?

Thanks for your help

Pinout is in the GitHub, the protocol is SMBus. Would recommend against it due to the risk of blowing up your mainboard.