Steve's barking at special electric cars

I just don't get it. Why are we investing in plug in cars when we can just as easily put money into electrical cars that can be charged by photosynthesis. You just put these solar panels on the roof of the car which charges up the batter, letting the car drive at  night with out . Now if it's cloudy all day the owner of the car can put the car in the garage turning on the lights to charge the battery. Now this would work like the panels that run  a solar power calculator only charging the battery instead of running the calculator. The owner would then save money on not buying gas or for that matter paying the electric company.