We shall see. Here in Texas during the summer you run air conditioners all night...and they only slow down around midnight (i.e., cycle less). I’m not sure about the 2 hours either - the Leaf was 8 hours, the other cars were 4 hours (at 240 volts).
The Leaf has a battery sized to allow 100 miles between recharges. If you actually drive 100 miles every day, then a 5000 watt charger would run 6+ hours.
The math is not complicated. A well designed electric small sedan or sports car will need between 160wh (the GM EV1) and 250wh (the Tesla) per mile. Figuring 4 miles per kwh is conservative unless the vehicle is a van or truck. The Volt will cover 40 miles under regular driving (25 leadfooting it and 50 babying it) on the 10KWH of battery power it uses before it turns on the engine to prevent the battery from further discharge. So the Volt is figuring 250wh per mile as an average. Charging at 5000 watts, 240V and 21A, that would require 2 hours to replenish the 10KWH.