Lei Bao

The trick here is that since the battery charge faster when they are empty, you want to only charge what you need to get to the next charger. The more charge that’s in the battery, the slower it charges, which in practice means that you want “just enough” charge in the batteries to get you to the next charger. As a rule of thumb, it takes 20 minutes to go from 0% to 50%, then 20 minutes to go to 75%, then 20 minutes to go to 87%, etc. The return on investment time goes down the higher you charge it.