PV Charging Station for Plug-in

After I had my Plug-in Prius a whille it dawned on me that getting electricity from coal-fired power plants or nuclear reactors maybe wasn't the highest plan for the environment.  So I considered installing PV (photo-voltaic) panels on the roof of our garage, so that I could charge the batteries with solar power.  I calculated that I would need 5 kWhr to get a full charge and that a 3 kW array would be able to produce roughly 8 kW on average per day.  Our roof, with space for twelve 230 watt PV panels, supplies 2.76 kW.