Solar panels on EV cars

Often I've wondered why all EV cars don't have a roof made of solar panels.
Sure that isn't going to charge up that huge battery quickly, but every little bit helps IMO.

EV cars seem to be a sunny climate thing, and if they sit outside for hours per day in the sun, that is still some power.
Heck if its only 2% a year, that is still a lot of electricity considering that massive battery.

It should also help them appear to be more green.

But if a million EV cars have to charge 2% less off the grid, that helps ease the strain on the grid, and also saves coal and natural gas being burnt.
Toyota did with some of their hybrids in Japan, but not US market. Rationale was market study showed US buyer preferred pano or sunroof, which was mutually exclusive from solar.
 
If we are using my cabin as an example, it has no electricity to it. Everything is propane only, fridge, stove, heat, lights.
There are a lot of posts on off-grid solar projects. I took a course on it and found the general recommendation was to create storage system consisting of 10 or so a deep cycle lead acid batteries sealed in a box with a vent system to the outside. This would provide enough power for cloudy days for about 3 days of storage. The fridge, stove and heat would still be propane, but the LED lights and household power for the coffee grinder, radio, heat circulation fan, etc would be from the panels. The costs for the panels and inverter would be $2-$3 per watt for a system. Of course you would have to clear away enough trees to provide a clear exposure for the panels.

Certainly the talk of eventually using the lithium ion battery packs from wrecked Tesla’s is interesting but any large use of that is probably still 10 years away. We’ll probably see some hillbilly installations on the Net in coming years.
 
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Knight Rider had an episode where there was some sort of rally race of vehicles using alternative energy sources. One car was covered with solar panels, but even back then I was thinking no way since it would be generating less than the equivalent of 1 HP even with maximum sunlight. KITT was supposed to be powered by liquid hydrogen, although I remember during the series he said he could run off of any combustible liquid. Also, the last Knight Rider reboot series supposedly had a Mustang based hybrid that included solar capture.

I found a clip and it was worse than I thought. It wasn’t even fully covered with solar panels. And when the car move forward they give it a roar like a muscle car engine.

 
Toyota did with some of their hybrids in Japan, but not US market. Rationale was market study showed US buyer preferred pano or sunroof, which was mutually exclusive from solar.
I thought there were some in the US in a small amount of Prius that would charge the 12v battery that could run the A/C at any given time. I remember that from somewhere, but that could also mean it was total BS and I made it up.
 
Then the solar panels setup in the fields are a waste of money if that is the case, but I believe a full roof panel would make a big difference.../???
Apples to oranges. The space on a car roof is too small to make an impact that is worth the cost.

Btw, I think taking up farmland with them is silly and a waste, given the modest amount of power they actually produce, and only during daylight. Put them on roofs and over parking lots. Farmland needs to stay farmland. Just my humble opinion.
 
I think something like a 4 seater, 4 wheel Aptera could be a practical commuter/second vehicle for a lot of people, that could mostly charge itself. It could also do some neat tricks like reorienting itself to track the sun for maximum charging if you had the parking space.

The current super heavy/powerful EV's don't have the surface area to charge themselves because they are tied down to a huge heavy energy hungry battery and therefore heavy chassis, and then big wide inefficient tires, etc.... Although because they are so heavy, having a flip out solar array on the roof to quadruple the panel area would be possible without compromising CoG or aero either...
With all these SUV power trunk actuators around, adding some auto tracking component might be easyish to do as well?
 
Often I've wondered why all EV cars don't have a roof made of solar panels.
Sure that isn't going to charge up that huge battery quickly, but every little bit helps IMO.

EV cars seem to be a sunny climate thing, and if they sit outside for hours per day in the sun, that is still some power.
Heck if its only 2% a year, that is still a lot of electricity considering that massive battery.

It should also help them appear to be more green.

But if a million EV cars have to charge 2% less off the grid, that helps ease the strain on the grid, and also saves coal and natural gas being burnt.
The biggest reason is that the ultra efficient solar panels that would be of use are still extremely expensive. Most solar panels only provide enough juice to power the dome light and maybe the radio?
 
FWIW this is what a solar powered car looks like. There are attempted variations into passenger cars but none exist as of yet.

solar car.webp
 
Often I've wondered why all EV cars don't have a roof made of solar panels.
Lightyear and Sono tried it - with a lot "this is the future" marketing ******** bingo - and went belly up with that concept.
The additional miles they claimed are pretty much under lab conditions where the sun shines every day for 12 hours from the perfect angle. Real world additional miles was more like 2-4 miles a day. Not enough to offset the high cost of the cells.

Aperta and Squad Solar are still trying - not sure if you can call this vehicles a car though.
 
There are a lot of posts on off-grid solar projects. I took a course on it and found the general recommendation was to create storage system consisting of 10 or so a deep cycle lead acid batteries sealed in a box with a vent system to the outside. This would provide enough power for cloudy days for about 3 days of storage. The fridge, stove and heat would still be propane, but the LED lights and household power for the coffee grinder, radio, heat circulation fan, etc would be from the panels. The costs for the panels and inverter would be $2-$3 per watt for a system. Of course you would have to clear away enough trees to provide a clear exposure for the panels.

Certainly the talk of eventually using the lithium ion battery packs from wrecked Tesla’s is interesting but any large use of that is probably still 10 years away. We’ll probably see some hillbilly installations on the Net in coming years.


While great information, my cabin will never be solar powered.
We get winter here, 20 feet of snow, -45 temperatures, and I'm not going out there every snowfall to clean off the solar panels.
So they will not be charging, and then the batteries will go dead, freeze, and die.
Propane appliances just sit there turned off, and when I go to the cabin I light them, and they work.
The cabin has no running water, we take drinking, cooking, dishwater with us.
My jumpstarter power pack comes along to charge phones. In winter we don't get there during the coldest days, we will go at -15 C and snowmobile, ice fish, sit around the fire pit.
 
I like the idea, practicality aside.

Say you have a lot of roof space, say you could fit 300w of panel up there.

in an open parking lot, hot day, direct sun, cars get cooked, even in cool northern climates. Say parking 8 hours a day in a parking lot, you could generate 4 hours full capability and 4 hours 50% capability. So 4*300+4*150 = 1800Wh.

The car uses about 200-250Wh/mile, call it 250. So you get about 7 miles of range from parking all day.

For me it would offset half of my commute, roughly. Worth it? Sort of. But practical to make a real dent? no.

I wouldn’t mind having it. I don’t need a super giant sunroof. Id rather add more energy free than not. If they could do it for next to no money I’d take it. But it isn’t going to make any real dent in any use profile unless you live just a few miles from work. And even then its utility is limited.
 
I thought there were some in the US in a small amount of Prius that would charge the 12v battery that could run the A/C at any given time. I remember that from somewhere, but that could also mean it was total BS and I made it up.
The Prius, don't remember what years but I had one of them, had solar in the roof. You could switch the system on/off. When on, when the ambient temp exceeded 85 (I think) it would turn off the recirculate function and activate the fan only of the A/C system. I had Weathertech window vent shades so the windows were also down an inch or so. When I'd get into the car the temp was basically identical to the ambient, upper 90's around Houston. Much less oppressive than the usual 14x degrees inside the typical closed car. Excellent feature. Wish all cars had it.
 
The Prius, don't remember what years but I had one of them, had solar in the roof. You could switch the system on/off. When on, when the ambient temp exceeded 85 (I think) it would turn off the recirculate function and activate the fan only of the A/C system. I had Weathertech window vent shades so the windows were also down an inch or so. When I'd get into the car the temp was basically identical to the ambient, upper 90's around Houston. Much less oppressive than the usual 14x degrees inside the typical closed car. Excellent feature. Wish all cars had it.
Thank you for confirming I'm not losing it. 😂 I always remember a lot of weird facts, mostly automotive. Serves me no real purpose in life but I enjoy it.
 
I like the idea, practicality aside.

Say you have a lot of roof space, say you could fit 300w of panel up there.

in an open parking lot, hot day, direct sun, cars get cooked, even in cool northern climates. Say parking 8 hours a day in a parking lot, you could generate 4 hours full capability and 4 hours 50% capability. So 4*300+4*150 = 1800Wh.

The car uses about 200-250Wh/mile, call it 250. So you get about 7 miles of range from parking all day.

For me it would offset half of my commute, roughly. Worth it? Sort of. But practical to make a real dent? no.

I wouldn’t mind having it. I don’t need a super giant sunroof. Id rather add more energy free than not. If they could do it for next to no money I’d take it. But it isn’t going to make any real dent in any use profile unless you live just a few miles from work. And even then its utility is limited.
That sounds overly optimistic, we don't get 4 full hours even with ground-mount up here, which is the best possible scenario.
Don't mind the metering error on the one farm. This is yesterday, installed capacity is 478MW:
Screen Shot 2023-07-17 at 2.03.35 PM.webp


Today is very sunny, I'll post today's output later when the site is updated.

Rooftop in Ontario has about 10% capacity factor, and that would have superior angling to a car roof, which is why I estimated around 5% CF for this application.
 
While great information, my cabin will never be solar powered.
We get winter here, 20 feet of snow, -45 temperatures, and I'm not going out there every snowfall to clean off the solar panels.
So they will not be charging, and then the batteries will go dead, freeze, and die.
Propane appliances just sit there turned off, and when I go to the cabin I light them, and they work.
The cabin has no running water, we take drinking, cooking, dishwater with us.
My jumpstarter power pack comes along to charge phones. In winter we don't get there during the coldest days, we will go at -15 C and snowmobile, ice fish, sit around the fire pit.
Here they're pushing for everything electric so we'd have to give up the propane, and firewood. Maybe you can buy a windmill if they were to successfully push the same nonsense on you. ;)
 
we use the most efficient conformal solar cells we can find, on the “turtleneck” of our motor glider. It powers the avionics when the engine is off. The avionics battery is a 12V 9AH that will run the avionics for about an hour. With the solar, we can fly all day.

I ran the numbers. If one were to cover a Model S, with these cells, including the rear window surface, such as on a louvered shade, the real world output would be about 1000w.
 
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