– Why do electric cars not have solar panels on rooftop so they could be charged while driving/parked
In: Engineering
Because the amount of power it would generate would only be enough to move it a couple miles and it would add weight, complexity, and cost that just wouldn’t be worth it.
Some do but mostly it isn’t worth it, they are not light, and not an ideal roof covering anyway. I imagine as we get better materials it will happen more often. Some thin film thing.
There isn’t anywhere enough surface area on top of a car to put enough solar panels to charge a battery at any meaningful rate.
This was actually something that people demanded in the resurgence of electric vehicles. Toyota Prius even went so far as to actually install a practical solar panel which would help run the air condition and the battery topped up while parked. However a full size solar panel covering the entire roof would be quite heavy and expensive without actually making much of a difference when driving the car. It takes a lot of energy to power a car. The weight of the solar panels is probably going to slow the car down more then it speeds it up reducing its length between charges.
It’d only probably be worthwhile on semi trailers, and maybe not for really helping with drive power, but for auxiliary power for things like refrigeration.
Some of them do, but they are mostly for running accessories, and don’t typically contribute much (or at all) to the main “driving” battery.
There’s not a whole lot of surface area on a car, so you are only looking at a few hundred watts at most.
It is probably worth mentioning Aptera, who is still in the alpha/beta stage, however, they are making a vehicle with the goal of being as efficient as possible, so they predict they will be able to get a nontrivial amount of charge if the vehicle is parked in the sun for most of the day.
They are about to be produced in the old Saab works in sweden by German company [Sono Motors](https://sonomotors.com/de/) very soon.
This car will be very light, and also very affordable at only 25’000€, the same price for many cars that size. On average, in Europe, including nights and shade, the solar panels give you 112km or range per _week_. If you consider that many people within a city will drive about 10-15km to work one way each say of the week, you’ve got them covered pretty well with just that. Even without any sun, it’s a cheap electric car with 300km range and quite some cargo!
They should – I’ve seen them on top of RVs, sailboats and all kinds of other vehicles. Hell sail boats claim they’ll recharge their batteries in no time. Granted they don’t need as much as a car but when a car is parked all day at work or outside your home, it could easily be making more electricity.
There *are* vehicles powered by on-board solar panels, but they’re impractical for ordinary use. I mean, look at this picture:
https://en.wikipedia.org/wiki/World_Solar_Challenge#/media/File:World_Solar_Challenge_2015-Parade_at_Victoria_Sqare_in_Adelaide,_Australia.JPG
> The 2017 Cruiser class winner, the five-seat *Stella Vie* vehicle, was able to carry an average of 3.4 occupants at an average speed of 69 km/h (43 mph).
https://en.wikipedia.org/wiki/World_Solar_Challenge
It would not be good while driving, but while parked it might.
The issue is that you would have to compete on cost and convenience with just installing solar panels on your garage and using the power to charge it while plugged in.
What this might help with, would be the people who still cannot even consider getting an EV, because they don’t live in a place where they can plug in their car over night to charge.
We still have a ways to go on efficiency before it is worth it though.
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