That's 53,000W / (110V * 15) = 32.12 hours.
So if you plan to get yourself a plug-in electric car with any kind of serious range, be prepared to have an electrician install a high current outlet to charge it. At the very least you'll want a 220V/40A circuit for overnight charging in 6-7 hours.
[Source: Greenwich Time
The gang from Tesla left their Silicon Valley home base to pay a visit to the vicinity of the Big Apple this week. Part of the purpose of the trip was to spend some time with some of the people in the area who've plunked down cash toward a Roadster but haven't yet taken delivery (which would be almost everyone on the customer list at this point). One interesting note in the article from Greenwich Time is the length of time required to charge up the Roadster's battery. They note that charging the battery from a normal household outlet could take up to 30 hours. The Roadster's battery has a capacity of 53kWh. Tesla quotes a charge time of 3-3.5, but that is based on charging from a 220V 80A circuit. If, on the other hand, you plug the car into a typical outlet in your living room, you would only have 15A flowing at 110V.