Why Don’t Electric Cars Use Solar Roofs?

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I get asked a lot of questions on Quora. A recent one involved solar panels on the roofs of electric vehicles. Here’s my quick answer:

Why don’t Tesla or our electric/hybrid cars use solar roof on car for charging along with other charging options? Isn’t it cool that my car is parked in sun and it’s charging by the time I get a slot on fast charging point.

Several reasons. First, it’s expensive without much payoff. Second, making the panels look good and be aerodynamic means far less efficiency for those panels. Third, the power gathered, even at optimum, would barely make a dent in the car’s battery needs.

The reality is that panels are far less efficient than any other charging method. Most of the vehicles I’ve seen with panels on their roofs are using them to either power internals (say an RV parked for long periods) or to operate climate control systems within the car while it’s parked. The latter is the better option for a passenger vehicle that’s going to incorporate solar panels for any reason.

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