Not necessarily. I'm not particularly familiar with the weight of the metal skins of cars, but it doesn't seem obvious that a solar panel is heavier than the me

Not necessarily. I'm not particularly familiar with the weight of the metal skins of cars, but it doesn't seem obvious that a solar panel is heavier than the metal it would be replacing. A typical 1kW panel weighs about 40lbs, of which about 9lbs is the actual silicon producing the energy, and the rest is the protective glass, silicon backing, and structural material around the edges. It seems to me that if the panel is specially made to fit into a car roof as-manufacturered in place of a metal roof, a lot of that wouldn't be needed as it would be built into the roof anyway, and the added panel weight would be pretty negligible. The DC produced by the panel can also be directly used to charge the battery, no need for inverters.