Minimum charge on arrival AT CHARGERS

For the slightly paranoid (but also bitten) people like me, I’d like to specify «plan so I never arrive at a charger with less than X% battery left». I don’t want to start worrying right away when consumption goes the slightest above expected. Life is too short to spend it worrying about whether you’ll make it or not, or whether the trip will take longer than planned b/c of an unexpected charge stop/detour.