Contrary to popular belief, you don't need to prime a new lithium-ion battery. This means you don't need to fully discharge and bill the initial cycle of the battery. Lithium-ion batteries have maximum capacity readily available from the start and also the 1st fee is no different to the 10th fee. You could attempt to apply a tiny billing voltage to the battery, as little as you like, and then determine how much existing flows right into the battery.