The problem is these companies ask you to return the car at at least 70%. Or levy a 20-30 dollar charging fee. So that only leaves say 10% of margin between the

The problem is these companies ask you to return the car at at least 70%. Or levy a 20-30 dollar charging fee. So that only leaves say 10% of margin between the optimal charging level (80%) and the minimum level at return. I won't want to take the risk of being charged a charging fee and so will instead try to over-charge. I am ok if they charge reasonable rates (like say $2 per 10% of battery) for the recharge. But that's not what they do.