It could be good, but there is a conflict with one of the electric car hurdles: range anxiety. I use a level 1 charger at home which works fine for regular use - but it does take about 4 days to charge a nearly-depleted battery up to 80%. I'd be loath to give up energy that takes such a long time to get back. But this system would presumably require a level 2 charger, and that might make it ok. Still I can imagine objections over not having a car charged when you want to make a longer, last-minute trip, and over battery depreciation due to more cycling.