Why build charging stations, when you can add solar charging to roof of the car and then never have to go to a charging station? I want one. Can you build that?
That would probably yield 3 miles of range on a bluesky day. Totally not practical.
the problem with solar cells on the roof is that they are not in a good position to catch the sun. there's a reason why you havn't seen any flat solar panels on roofs. There are cars wich have solar panels on the roof, they normaly are for a small ventilator to keep the cabin cooler when parked.
There isn't enough real estate on any car, for solar to make any difference (well, other than maybe help re-charge the 12 volt battery).
From what I understand, the roof solar-unit on the Fisker: Karma just helped power the dashboard, and that was it. Also the cost of it far outweighed the efficiency of it.
JRoshtop Elon said with current technology in the solar field even using the best Solar cells available you would yield at most 10 miles per year! Not very fast