Although its better than a poke in the eye with a blunt stick...

Although its better than a poke in the eye with a blunt stick solar panels on EVs don't do a hell of a lot of good.

The incoming sunlight while the sun is overhead works out at about one kW per m². Current high quality solar panel efficiency is around 30% and there is about 5m² of upwards facing area on a medium sized car. An efficient EV uses 15 kWh per 100km so one hour of full sun will give you about 10km of extra range or less.