A solar panel would obviously not cover the usagebof a consumer car while it is being driven.

Consumer cars spend most of their time not being driven. If someone commutes 10 miles to work each day, they would nearly never need to charge the car.

Right, but for a fan, it would work. Cars heat up mostly in direct sunlight. The solar panel could be wired directly to a fan. This would also prevent heat death of dogs and forgotten children.