Reno
Great question but how can it be answered? What size motor? what voltage? How many VA is consumed? hard or soft push on the pedal?
Charger can be slow or fast. Big and small.
Use a 1 amp charger and it will take longer than a 12 amp charger which could be used on the 15 amp outlet. Upcoming code changes suggest the slow chargers will need a 20 amp T-slot so maybe a 15 amp breaker would trip after an hour or two.
There will also be some high rate chargers and those plugs will be much bigger than 20 amps but still less than generic.
I expect there will be cars that cannot be fully recharged overnight if they get close to flat in the day and I assume most battery technology won't allow a complete discharge either. But an 8 hour charge at 120 volts and 16 amps should push 15,360 VA back at the battery. I can't actually know how much will get saved in the battery due to the efficiencies involved. So for sake of this discussion a code compliant 20 amp Tslot from a 120 volt outlet can give you a charge rate of about 1900 VA with no loss due to efficiencies.
