Are the solar panels even efficient enough at those angles to the sun to generate more electricity than they cost in weight?
Yes, by a small amount, unless you live in the arctic circle or something.
But does that mean they’re worth it? Probably not. There’s the financial cost as well as the weight. Plus potentially eating into head room. Plus it’s another thing to potentially go wrong.
I certainly see the use case for campervans - a large flat roof is ideal, and being able to park for a couple of days and charge a leisure battery without flattening your main battery or running an engine seems perfect.
But for a passenger car, the use seems more limited.
Maybe with some of the super cheap perovskite cells coming out? Maybe.
It’s a very marginal idea, at best. Even in equatorial regions under perfect weather, there just isn’t that much solar power you can collect with the space of a car roof.
Aptera is attempting to do this. They had to engineer their own solar panels for the car. Probably the closest thing they have to production ready. They also had to make the car super efficient to make it work. Peak output of their design is about 700W
Geeze, a <$1000 e-bike conversion kit can put out more than that.
So, fewer than 10 miles per day in perfect conditions?
700 watts = .7 kW
If you figure 10 hours of that (or longer but with less-perfect conditions) you can get 7kWh. I estimate about 3.5 miles per kWH on my Bolt. Not sure this car’s efficiency, but it gives us a ballpark number. That would give about 25 miles of driving. I understand that there are plenty of other factors that can go into this, but “fewer than 10 miles in perfect conditions” isn’t necessarily accurate either.
I would respectfully argue that 5 hours of peak output equivalent is more realistic as that’s what you’d get from static panels at the proper angle. But I didn’t figure in the claimed efficiency of the car.
My car, Ford cmax energi, was tested with a 500 watt panel and that only yielded 5 miles a day in great conditions. More like 2-3 miles most days, and that’s at roughly 300wh/mi., similar to your bolt. Never made it to production with solar.
This is a real bummer. I saw these guys on The Fully Charged Show a couple of years back and their first car looked incredibly promising. But the auto industry is not easy to break and investors know that. Hopefully the solar roofs will prove profitable enough for them to try again.
IIRC, part of the reason why and how they declared bankruptcy and restarted was because they then no longer had to fulfil any preorders (but also didn’t pay customers back due to the bankruptcy). So customers got screwed over.
Car industry is difficult but these kinds of practices sound extremely fishy.
I was not aware of that! Thank you for mentioning it. It has always seemed crazy to me that customers have no charge over assets on bankruptcy. In a better world, that’d be the case but that’s not the world we live in.
As an aside, this is the sort of thing that is going to hinder investment in small firms in the auto industry, further compiling the issue of a few manufacturers setting ridiculous prices for their vehicles.