# Is it feasible to put solar panels on the roofs of cars? **URL:** \ **Category:** Factual Questions\ **Created:** [September 22, 2018, 2:00pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731 "2018-09-22T14:00:30Z")\ **Posts on this page:** 19\ **Page:** 4
**Author:** ![Great\_Antibob](https://avatars.discourse-cdn.com/v4/letter/g/e47c2d/32.png) [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)\ **Post date:** [June 26, 2019, 4:16pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/62 "2019-06-26T16:16:33Z")
> [@Dana\_Scully](#): > > Are you referring to the often cloudy skies? We live in the Seattle area and, as I mentioned previously, have solar panels on our roof. In the context of home electricity, solar is fine. Germany has a lot of solar acceptance, and it’s much further north than the PNW. But in terms of powering automobiles, solar is not practical/effective for a number of reasons given above, some of which are exacerbated by geography. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [June 26, 2019, 4:20pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/63 "2019-06-26T16:20:37Z")
> [@Dana\_Scully](#): > > Are you referring to the often cloudy skies? We live in the Seattle area and, as I mentioned previously, have solar panels on our roof. One of the things we looked into before we took the plunge (the initial price tag was about $20K although with rebates from Washington state and other entities it came to much less) was that aspect. Even on cloudy days plenty of sunlight gets through to make them feasible, and we “sell” the excess energy back to the power company. Often in the summer we have very low bills despite our copious use of a/c. And it’s not unusual for us to have a credit balance on our account at that time of year. Notes: 1. I was talking about trickle charging … 2. in the context of _cars_. If you want to brag about your solar house, whatever. But we’re talking about cars here. Small area. Weight limitations. Variable orientation. Throw in some clouds and the numbers get even worse. Etc. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 26, 2019, 6:57pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/64 "2019-06-26T18:57:00Z")
> [@Frankenstein\_Monster](#): > > I would buy one! > > Great for camping. It produces enough electricity to run a full size washing machine, dryer, dishwasher and microwave every day! There’s also the [e.home](https://inhabitat.com/meet-the-solar-powered-electric-motorhome-weve-all-been-waiting-for/) concept RV. Though the range is only 100 miles, and it doesn’t say how many days it takes to fully recharge the battery with the solar panel. It may still be practical for a relaxed RV lifestyle. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [June 26, 2019, 9:33pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/65 "2019-06-26T21:33:08Z")
> [@scr4](#): > > People don’t use the full range of the car in a day. If they do that regularly, they bought the wrong car. > > If the car gets 12 km of charge per hour from the solar panel, that’s almost 100km (60 miles) per day. That means the average American car commuter never needs to plug in their car, except when going on longer road trips or dark stormy days. Fair enough. I suppose it’d make parking garages rooftops cool again 🙂 ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [June 26, 2019, 9:57pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/66 "2019-06-26T21:57:19Z")
I’d love to have a solar-powered car, but… To be universally practical, a solar-powered car needs to be: [ol][_]Able to cruise at highway speeds continuously from solar input and/or battery[_]Able to supply a charge to the power train continuously during daylight hours, even in cloudy weatherAble to supply enough charge to a battery or other storage device that will power the car without sunlight for 16 hours, the amount of a winter night at temperate northern latitudes.[/ol]Until that happens, I will be driving my cheap, gasoline-powered jalopy at a considerable saving, without worry about the time of day and/or night. ---
**Author:** ![busterpickle](https://avatars.discourse-cdn.com/v4/letter/b/258eb7/32.png) [@busterpickle](https://boards.straightdope.com/u/busterpickle)\ **Post date:** [June 28, 2019, 11:19pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/67 "2019-06-28T23:19:26Z")
I don’t know how many of you have picked up a 2’x4’ solar panel but they are not that heavy. I don’t recall them being 20 pounds when I had two on a shed. Also, the panel on a car roof would be just the panel, could readily place the inverter elsewhere. Also, many boats use them and the panels they use are rated for salt, high wind, and hail. Again, not that heavy. I can see this making sense only if you happen to regularly drive to an area that doesn’t have a charging station to help maintain the battery. But, if there’s a plug somewhere possibly a portable charger could be used. Which would probably have better ROI over the life of the vehicle compared to panels. Maybe, if you had them on a roof rack and they opened up and you had the entire footprint of the car to work with. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [June 29, 2019, 3:00am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/68 "2019-06-29T03:00:05Z")
I just re-read _The Martian_ and noticed something. When Watney’s driving across country in the rover, he has a couple stacks of solar panels[sup]1[/sup] on his roof. Why didn’t he plug the topmost ones into the rover? Also should have plugged the RTG that he has for heat into the rover too. The RTG was used to help recharge the batteries, so why not use it during driving? He could have gotten 15 or 20 more minutes fo driving each day. [sup]1[/sup] The panels are only 10.2% efficient, which at the time he wrote it (published in 2011, so written some time before that) may have been better than what you could get for your roof. But NASA had already launched Dawn in 2007 (panels probably built around 2005) and that had triple-junction InGaP/InGaAs/Ge photovoltaic panels that had 27.6% efficiency. Weir didn’t do his homework on that. ---
**Author:** ![Frankenstein\_Monster](https://avatars.discourse-cdn.com/v4/letter/f/ccd318/32.png) [@Frankenstein\_Monster](https://boards.straightdope.com/u/Frankenstein_Monster)\ **Post date:** [July 5, 2019, 3:27pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/69 "2019-07-05T15:27:22Z")
Interesting news of a Toyota trial of cars that get a significant range boost from car mounted solar cells: [NEDO, Sharp, and Toyota to Begin Public Road Trials of Electrified Vehicles Equipped with High-efficiency Solar Batteries](https://global.toyota/en/newsroom/corporate/28787347.html) Interesting numbers in that news relase: Maximum charge to the driving battery while the vehicle is parked (per day):\* 44.5 km Maximum charge and power supply to the drivng and auxiliary battery while the vehicle is being driven (per day):\* 56.3 km \*according to the JC08 Japan test cycle I would prefer to see kWh numbers but I guesstimate those numbers are roughly 4.5 and 5.5kWh (JC08 is hopelessly optimistic) And they seem to be using triple junction cells which are impossibly expensive (I wonder if that is ever going to change). ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [July 23, 2019, 6:38pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/70 "2019-07-23T18:38:15Z")
Yet another example from the marketing gimmick world: [Hyundai adds solar panel to a hybrid](https://cleantechnica.com/2019/07/22/the-solar-roof-on-hyundais-new-sonata-hybrid-adds-1300km-of-range-per-year/) ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 1, 2021, 5:32am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/71 "2021-03-01T05:32:52Z")
Bumping this ~~thread~~ topic to report on the latest solar-paneled vehicle: > **[Aptera Motors](https://aptera.us/)** > > Aptera is the world’s first Solar Electric Vehicle that requires no charging for most daily use - giving you the freedom to do more with less impact on the planet. It’s basically what you’d get if you converted one of those World Solar Challege vehicles to be street legal. Because that’s basically what they did. OK, it does have a battery, which the WSC vehicles do not, or at least I don’t think they do. They claim you can get 1000 miles with the 100 KWh battery. ---
**Author:** ![Allen28](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@Allen28](https://boards.straightdope.com/u/Allen28)\ **Post date:** [March 1, 2021, 8:05am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/72 "2021-03-01T08:05:22Z")
It is really a great idea. but what about the third world countries especially in Asia and Africa.? they even don’t have electricity. they are facing loadshedding everyday for 4 to 5 hours. However the idea is great and where it can be implemented . it must be used. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 1, 2021, 9:41am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/73 "2021-03-01T09:41:12Z")
If you lived in Phoenix AZ, in a small apartment so you have no place to put solar panels except on the roof of your car, and you only travel a couple of miles a day on average, then solar panels on the roof could provide up to 50% of your power. It’s not all that much to begin with, in a conventional car you might be using 1 gallon of gas a week in that scenario. From that low usage point upward the power provided by the rooftop solar panel rapidly becomes insignificant, and if you have a house or a yard you can use many more fixed solar panels to charge your car or an external battery. So the upshot, good for low usage with no other place to put solar panels, in high sunlight zones. ---
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [March 1, 2021, 2:51pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/74 "2021-03-01T14:51:50Z")
> [@TriPolar](#): > > So the upshot, good for low usage with no other place to put solar panels, in high sunlight zones. Though it would still be better to just put the solar panels on stilts over the driveway/parking spot. The stilts would cost less than fitting the panel to the car, and it would be more reliable. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [March 1, 2021, 2:54pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/75 "2021-03-01T14:54:39Z")
Would it be enough to run the AC or the fan in the summer so the car is more comfortable to to return to? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 1, 2021, 3:06pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/76 "2021-03-01T15:06:48Z")
Yes, it’s a very limited set of circumstances where the car top panels are a true benefit, perhaps if you can’t put up a car port with solar panels on the top because you don’t even have a fixed parking spot. There have to be upwards of 10-12 people in the American Southwest who would meet these criteria. I’m sure the car manufactures are refitting their plants as we speak to take advantage of that market. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 1, 2021, 4:02pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/77 "2021-03-01T16:02:03Z")
> [@Dewey\_Finn](#): > > Would it be enough to run the AC or the fan in the summer so the car is more comfortable to to return to? Not the A/C. Typical automotive A/C compressor needs a few kilowatts of mechanical power, whereas we’re talking about maybe getting a couple hundred watts from a rooftop pane. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [March 1, 2021, 4:12pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/78 "2021-03-01T16:12:47Z")
[Maybach (ultra-luxury Mercedes brand)](https://auto.howstuffworks.com/maybach.htm) vehicles had the option of solar panels to run a ventilation system when the car was off. Not sure how well it worked. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [March 1, 2021, 7:06pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/79 "2021-03-01T19:06:20Z")
You can do that today. But apparently there’s not much call for either to be integrated into the car as a factory-standard accessory. > **[Amazon.com : SUNER POWER 12V Solar Car Battery Charger & Maintainer, 2.4W...](https://www.amazon.com/SUNER-POWER-Battery-Charger-Maintainer/dp/B07G5F9TGV)** > > Amazon.com : SUNER POWER 12V Solar Car Battery Charger & Maintainer, 2.4W Waterproof Solar Trickle Charger, Portable Solar Charger, High Efficiency Solar Panel Kit for Deep Cycle Marine RV Trailer Boat : Patio, Lawn & Garden [Amazon.com: Solar Powered Car Fan Auto Front/Rear Window Air Vent Exhaust Fan Vehicle Radiator Vent with Ventilation(Black): Kitchen & Dining](https://www.amazon.com/dp/B07BPV59BP?tag=spgenie-20) ---
**Author:** ![Martin\_Hyde](https://avatars.discourse-cdn.com/v4/letter/m/47e85d/32.png) [@Martin\_Hyde](https://boards.straightdope.com/u/Martin_Hyde)\ **Post date:** [March 3, 2021, 8:22pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/80 "2021-03-03T20:22:07Z")
In the “boondocking” community (basically RVing, usually with aftermarket commercial vans converted for the purpose, specifically done away from established campsites with hookups), solar panels on the vehicle roof are becoming quite common. However they’re largely there because people deliberately trying to do RVing without any hookups are trying to find anything they can to lengthen their “tether.” The typical setup will have a battery bank of deep cycle style RV batteries, these batteries will often be setup so they can be charged by either the solar panel (generally the preference if conditions are right) or the vehicle’s engine. An inverter is used to power common electronics from the batteries. This setup is often quite sufficient for things like laptops, lighting, TV, and some other light appliances. Cooking and heating are often done by propane and sometimes wood stoves (there are boondocking wood stoves some people install where they vent it through a cut-out in the roof of the van), as it would be difficulty to heat a vehicle in cold weather or cook from the amount of electricity you can get from van rooftop solar. If an air conditioner is needed it’s almost always going to be powered by a dedicated generator as there aren’t a lot of great options otherwise. It may seem like solar isn’t doing much, but if you’re boondocking in weather where you don’t really need cooling or heating, and you’re cooking on a propane or charcoal grill outside the vehicle, the solar panels and batteries can keep a lot of your creature comforts like TV / internet / laptop going indefinitely. [Previous page](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731.md?page=3)