A small car with 70 HP needs an electric power of 51 KW. The solar energy is 1.366 kilowatts per square meter, so this small car with require a solar panel with 38 square meters area, something like 4m x 9m or 6m x 7m that is of course much bigger than this small car and I have assumed 100% energy efficience in the conversion.

Stupidity also evolves!