For the 1000th time. It's not about generating the electric. A home solar array can do it. The problem is the time and more importantly the inability of the vehicles to meet driver's needs. If they made one that did they wouldn't be able to keep up with demand. All the other arguments are moot.
Time? In a grid parallel system you put kW's on the webb during the day, and take them off at night. At the end of the month, if you use more than you put on, you pay. If you use less, you have a credit for the next month.
And it's the grid power that you MUST use to recharge the battery in a timely fashion. Left entirely to the PV panels it is a month. Regardless, the payback of the panels will not pay for the grid power used.