SinConnect and Electric aircraft

I was wondering, now that there are a few electric aircraft on the marketplace, how would we read the amount of battery power used or the current battery level.

I am thinking of this in the context of virtual airline management. Right now I have a system were I can read how much fuel is on the aircraft and by comparing the start and end of flight how much to calculate for fuel expenses, but with electric its a bit of a mystery, I don’t think I can use the fuel variables, since the battery level is not measured in liters, gallons, kg or pounds.