[gruez]

>Currently charging at night at home is cheaper today, only because power company makes it so. Ideally cars should charge when the sun is up, in day time.

Power's cheaper at night because demand's lower. The sun being out during daytime does make more solar power available, but there's also higher demand because everyone's awake. Unless there's evidence to the contrary, I'm inclined to believe that night power is cheaper because of pure market forces, rather than being dictated by the power company.