It’s not that it’s far-fetched. It’s just impractical. Solar panels don’t really generate that much power per square foot. Charging a car with just the roof can take days.
One model of solar roofed electric car on the market recharges ~20 miles per day with the roof.
Charging stations are a way better idea for road trips in electric cars, as is plugging the car in overnight. This is great for a remote hermit, but more interesting for the hack value than a practical option.
It protects the car, it’s a way for the greater battery drain an electric car probably has to be offset. It’s like carrying around an extra tank of fuel. It could genuinely save lives whilst electric cars develop. Soo many reasons yes vs weight gain.
Edit: even weight gain is going to be negligible if the panel is implemented like a sunroof and see through. That would be lighter than metal and only the solar charge controller is added weight. Considering there are controllers for charging anyway this maybe less than I imagine.
Light weight panels tend to produce less power. The best ones are opaque and have a thick glass layer on both sides of the circuitry - so they’re not super light. Also the glass would need to be strong enough to handle rocks/etc as well as provide structural support in a crash (even if it’s just with the initial impact and then shatters similar to a car windscreen).
They could theoretically be light however in reality heavy panels might be a better choice.
But yeah I agree you’re on the money with protecting the car. This could make a big difference to the usable life of the battery by keeping it closer to the optimum charge level especially with a normal daily suburban to city commute.
Since the car stands still most of the day, some kind of system that folds out into multiple solar panels may be interesting, offering shade as well
That may be awful for urban scenarios such as parking lots
It could unfold front to back, covering the hood and the trunk, taking up no more space than the car itself.
Or like that umbrella solar system. Or even adaptable to available space. Obviously works best when camping
It’s also a way for people who regularly travel less than 20 miles (if this number is correct).
Most device consume more power than you can realiable get from solar on the device. You can’t power a cellphone from a back-mounted solar cell nor run a car from a solar roof alone.
But don’t make the mistake to assume that everyone has (cheap) power at home or that everyone has a (suburban) home. Photovoltaic is cheap and reliable. And you need space, so it makes sense to put solar everywhere.
One model of solar roofed electric car on the market recharges ~20 miles per day with the roof.
I wish they’d share the specs, but some back of the envelope math suggests you could get about the equivalent of a Level 1 charger from panels on the roof of a normal sized car. That lines up pretty well with your ~20 miles per day number with a typical EV.
This experiment is able to get about 500 miles of range from a single day of sunlight.
Obviously they made some serious usability (and aesthetic) compromises to get that - but most likely the biggest difference is just the weight of the batteries. This car has small batteries which means it doesn’t need massively power motors to accelerate up to speed.
For what it’s worth, my electric bicycle gets about 50 miles from a tiny battery. The solar panels on this car could theoretically charge my bike battery in ten minutes. Electric cars really are inefficient - you’re paying a massive price to be able to comfortably transport a family around, though obviously that’s worth it if you can afford to.
I’m not sure that it does. All the articles I can find word it as something like “has a range of 710 kilometers (441 miles) on a sunny day.”, without actually explaining it. I’m assuming that’s going from 100% charge to 0% charge, plus all the range gained by charging during the day.
They don’t actually say anywhere I can find how quickly it charges.
Also, looking up some other articles about it, apparently there’s a bunch of extra fold-out solar panels in the trunk
If you wanted maximum range, you’d start before dawn, drive most of your battery away, park somewhere all day to use that solar awning for all its worth, then continue driving at dusk.
