People will figure it out. Parking lot owners will have an incentive to provide charging stations; leave your car keys to the attendant and they'll get to it over the day.

More meta: our inability to see solutions to minor roadblocks never mean something won't happen. It's similarly amazing to me how so many commenters here don't think insurance for self-driving cars is solvable in the US - while they're already being tested in several other countries.