Honestly it seems like a no-brainer to me to put a solar panel on the roof of electric cars to increase their action radius, so I figured there’s probably one or more good reasons why they don’t.
Also, I acknowledge that a quick google could answer the question, but with the current state of google I don’t want to read AI bullshit. I want an actual answer, and I bet there will be some engineers eager to explain the issues.
They have them on some international models of Hyundai electric cars. It’s not nearly enough to power the car or charge the battery, though. It’s more to just slow the battery down while it powers low-power things and look cool (it’s part of the trim package). Solar panels need to be way more efficient than they are now for them to really make a difference with such a relatively small surface area.
Even on ideal conditions (close to the Equator, no clouds) like in Northeast Brazil, you only get 5.5 to 6.0 kWh/m^2 of Solar energy, which means the roof of a small car, with 1 m^2 of solar panels, would only generate that amount of electricity if they were 100% efficient. That’s just 10% of the battery capacity of a small EV, like a BYD Dolphin.
My point is, even if solar panels doubled their efficiency, they would still only capture about half the energy of the Sun (currently, the best panels are at 24% efficiency), which means only about 2.5 to 3.0 kWh per day.