# 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:** 20\ **Page:** 3
**Author:** ![Sloe\_Moe](https://avatars.discourse-cdn.com/v4/letter/s/8797f3/32.png) [@Sloe\_Moe](https://boards.straightdope.com/u/Sloe_Moe)\ **Post date:** [September 23, 2018, 11:17pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/41 "2018-09-23T23:17:16Z")
I remember an Audi having a small array of panels on the roof for only one specific use: to power a motor and ventilate the inside when left in the hot sun with the engine off. It was a luxury car and it didn’t look all that tacky. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 23, 2018, 11:17pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/42 "2018-09-23T23:17:59Z")
The only way a full-solar car is going to be practical is if ALL cars are solar. There is no way to make car full-solar car that will survive a crash test. They are simply too light and flimsy. The Stella Lux weighs 827 lbs. It would be turned into splinters in a collision with even a Smart Car. Maybe some fantastic breakthrough in carbon-fiber manufacturing will fix that, but right now, it would be a deathtrap on the road. ---
**Author:** ![Moriarty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moriarty/32/49_2.png) [@Moriarty](https://boards.straightdope.com/u/Moriarty)\ **Post date:** [September 24, 2018, 12:25am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/43 "2018-09-24T00:25:17Z")
> [@beowulff](#): > > The only way a full-solar car is going to be practical is if ALL cars are solar. In the OP, I asked about a car that used solar energy to suplement the traditional engine because I doubted that a full solar car would be realistic, at least anytime reasonably soon. It sounds like it isn’t yet developed for fully powering even auxiliary features, but I’ll remain optimistic. If I can hijack the thread a tad, what about the possibility of using the wind that is generated from driving down the road for some power? Maybe little turbines in the front grill? Or is that also too minimal to be worth it? ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [September 24, 2018, 1:13am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/44 "2018-09-24T01:13:13Z")
Windmills do not work that way. 🙂 What extra power you gain by harnessing the wind would need to be made up by the extra drag on the car and thus the engine. It’ll take more energy to do that than what you would gain from the wind generator itself. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 24, 2018, 4:39am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/45 "2018-09-24T04:39:35Z")
> [@Moriarty](#): > > In the OP, I asked about a car that used solar energy to suplement the traditional engine because I doubted that a full solar car would be realistic, at least anytime reasonably soon. It sounds like it isn’t yet developed for fully powering even auxiliary features, but I’ll remain optimistic. > > If I can hijack the thread a tad, what about the possibility of using the wind that is generated from driving down the road for some power? Maybe little turbines in the front grill? Or is that also too minimal to be worth it? What you are suggesting is [this](https://www.youtube.com/watch?v=1VKS357zZaI), basically. ---
**Author:** ![sbunny8](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@sbunny8](https://boards.straightdope.com/u/sbunny8)\ **Post date:** [September 24, 2018, 8:05am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/46 "2018-09-24T08:05:17Z")
> [@Wesley\_Clark](#): > > My impression is an electric car can travel about 2-4 miles on 1 kwh of battery. So if you’re only getting 350W over maybe 4 hours, thats less than 5 miles a day of travel. The 2018 Smart Fortwo gets 3.23 miles per KWh. The 2018 Nissan Leaf gets 3.33 miles per KWh. The 2018 Chevy Bolt gets 3.57 mi/KWh. The 2018 Tesla Model 3 gets 3.85 mi/KWh. These are not outliers. They are typical. EVs that get less than 3 mi/KWh are quite rare. The Tesla Model X is one of them (2.7 mi/KWh). The vast majority of EVs on the road get between 3 and 4 mi/KWh. 350x4=1400 and a Chevy Bolt goes exactly 5 miles on 1.4 KWh (based on the average of city and highway combined). In city driving, it wouldn’t be hard at all to go 6 or 7 miles on 1.4 KWh. I do it all the time. An extra 6 or 7 miles per day for free would be nice. But I think it would make more sense to put the solar panels on your house rather than carry them around on the roof of the car. ---
**Author:** ![YamatoTwinkie](https://avatars.discourse-cdn.com/v4/letter/y/cc9497/32.png) [@YamatoTwinkie](https://boards.straightdope.com/u/YamatoTwinkie)\ **Post date:** [September 24, 2018, 3:12pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/47 "2018-09-24T15:12:42Z")
I see this thread has made it this far without an obligatory xkcd link: > **[Solar Panels](https://xkcd.com/1924/)** > > This works for a surprising range of sunlit things, including rooftops (sure), highway surfaces (probably not), sailboats (maybe), and jets, cars, and wild deer (haha good luck). ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [September 26, 2018, 5:29am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/48 "2018-09-26T05:29:21Z")
There’s a German startup, [Sono Motors](https://sonomotors.com/), that’s trying to bring a solar enhanced EV to market. [This article](https://cleantechnica.com/2018/09/25/get-ready-for-260000-electric-cars-with-solar-integration/) says they may be out in about a year and a half. It’s a minivan that has solar panels not only on the roof, but also the hood, sides, and back. They will add 30 km to its range. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [September 26, 2018, 5:57am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/49 "2018-09-26T05:57:30Z")
> [@sbunny8](#): > > They are typical. EVs that get less than 3 mi/KWh are quite rare. The upcoming Audi e-tron and the Jaguar I-Pace (ugh, 1995 called and want their names back) are both around 2.9 mi/kW-h. They, and the X, are all SUVs, so one might expect lower efficiency than a sedan. Also, the X is technically rated at between 2.95 and 3.16 mi/kW-h (75D vs. 100D). But yes, no EVs that I’m aware of are nearly as bad as 2 mi/kW-h. Also, the Model 3 at least (and probably others) can easily beat 4 mi/kW-h in city driving. ---
**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:** [September 26, 2018, 12:34pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/50 "2018-09-26T12:34:24Z")
> [@dtilque](#): > > There’s a German startup, [Sono Motors](https://sonomotors.com/), that’s trying to bring a solar enhanced EV to market. [This article](https://cleantechnica.com/2018/09/25/get-ready-for-260000-electric-cars-with-solar-integration/) says they may be out in about a year and a half. It’s a minivan that has solar panels not only on the roof, but also the hood, sides, and back. They will add 30 km to its range. Looks realistic, too! [Sion solar panels](https://sonomotors.com/sion.html/#Features) > [@Sono Motors](#): > > The solar cells in the car’s body mean that the Sion can easily charge its battery by itself throughout the day. The result is that the Sion can generate up to 30 kilometers’ extra range per day, completely free of charge. Of course you can also drive the Sion at night. After all, the battery has an actual range of 250 kilometers and can also be charged externally, regardless of the weather conditions. We use highly efficient, monocrystalline silicon cells for the solar modules. A total of 330 cells generate a maximum power of 1,204 watts with 24 percent efficiency. 330 cells is 5.5 panels’ worth. The quoted performance already accounts for the fact that not all the cells can be illuminated at the same time. Assuming the car has the equivalent of 3 panels’ performance in the optimal orientation, it should generate 5kWh on a good day. Assuming 16kWh/100km consumption (today’s Nissan Leaf), that will get 30km. I’ll be interested to see if they can actually fit those cells like in the picture and if they can actually get this kind of performance! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 26, 2018, 1:49pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/51 "2018-09-26T13:49:48Z")
> [@](#): > > Quoth **Moriarty** : > > If I can hijack the thread a tad, what about the possibility of using the wind that is generated from driving down the road for some power? Maybe little turbines in the front grill? Or is that also too minimal to be worth it? The absolute best you can do along those lines is to reduce the air resistance as much as possible. And, to be fair, a lot more can be done for that than most current cars do, but it’s at the expense of tradeoffs that most people don’t want. The biggest way to decrease air resistance is to reduce the cross-sectional area. Well, most of those competition solar cars have the driver basically lying down, and reduce the cross-sectional area to little more than the area needed to accommodate a lying person. ---
**Author:** ![tampora](https://avatars.discourse-cdn.com/v4/letter/t/9de0a6/32.png) [@tampora](https://boards.straightdope.com/u/tampora)\ **Post date:** [September 27, 2018, 2:08am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/52 "2018-09-27T02:08:11Z")
> [@Chronos](#): > > The absolute best you can do along those lines is to reduce the air resistance as much as possible. And, to be fair, a lot more can be done for that than most current cars do, but it’s at the expense of tradeoffs that most people don’t want. The biggest way to decrease air resistance is to reduce the cross-sectional area. Well, most of those competition solar cars have the driver basically lying down, and reduce the cross-sectional area to little more than the area needed to accommodate a lying person. But… you don’t always want to minimize drag. Make the car-windmills only interact with the ambient air when braking. On second thought, maybe stick with old-fashioned spring-loading Regenerative Braking. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [June 26, 2019, 5:09am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/54 "2019-06-26T05:09:52Z")
> [@Frankenstein\_Monster](#): > > Well I still think you are all wrong. A car that travels quite long distances on its own solar panels exists today and it is not a covered bicycle. > > It is the [Stella Lux](https://solarteameindhoven.nl/stella-vie/stella-lux/) which won the 2017 race. > > It generates 7-10kWh per day (my estimate) from its own 5sqm of solar panels and it travels 100km on about 4kWh (also my estimate). > > All of that is today, under favorable circumstances. > > That’s what they are trying to turn into the Lightyear One. Looks like these guys have a [prototype built](https://www.theverge.com/2019/6/25/18744078/lightyear-one-solar-powered-electric-car-release-date-price-range-features), at any rate. Won’t be availble for a few years and the price… if you have to ask, you can’t afford it. But they claim a 725 Km range. ---
**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, 8:52am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/55 "2019-06-26T08:52:15Z")
What the heck? What’s the point of the panels on that car at all? > [@](#): > > While the team claims that the car will get 450 miles ( **725 km** ) of range from its built-in battery, the real draw is the car’s five square meters of solar panels, which cover its roof and hood and can charge the car’s battery with up to **12 km of range an hour**. **It takes 60 hours, or 2.5 days, to get a full charge.** My god, just buy a used Tesla and pay for your local utility’s solar option. This whole exercise is a waste of time. Even assuming 100% efficiency, if every last drop of sunlight were converted into sweet, sweet power for your car, that’s still only 5kW. Tesla Superchargers are 150kW (30 times more powerful) and still take too long. Leave the solar panels off the cars because they’re just unnecessary weight and can’t charge the car fast enough. Save them for the parking lots and rooftops. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [June 26, 2019, 10:13am UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/56 "2019-06-26T10:13:35Z")
> [@Reply](#): > > What the heck? What’s the point of the panels on that car at all? > > **It takes 60 hours, or 2.5 days, to get a full charge.** My god, just buy a used Tesla and pay for your local utility’s solar option. > > This whole exercise is a waste of time. Even assuming 100% efficiency, if every last drop of sunlight were converted into sweet, sweet power for your car, that’s still only 5kW. Tesla Superchargers are 150kW (30 times more powerful) and still take too long. Leave the solar panels off the cars because they’re just unnecessary weight and can’t charge the car fast enough. Save them for the parking lots and rooftops. Agree - it would make much more sense to have fixed solar panels that top-up the charging stations, so you are still reducing the electricity demand but doing so more efficiently. Solar panels integrated into the bodywork of a car would make even the most minor fender-bender an expensive business. ---
**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, 1:03pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/57 "2019-06-26T13:03:43Z")
> [@Reply](#): > > What the heck? What’s the point of the panels on that car at all? > > **It takes 60 hours, or 2.5 days, to get a full charge.** My god, just buy a used Tesla and pay for your local utility’s solar option. 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. ---
**Author:** ![Dana\_Scully](https://avatars.discourse-cdn.com/v4/letter/d/5daacb/32.png) [@Dana\_Scully](https://boards.straightdope.com/u/Dana_Scully)\ **Post date:** [June 26, 2019, 3:18pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/58 "2019-06-26T15:18:30Z")
> [@scr4](#): > > I found [this article](https://mashable.com/2016/06/21/toyota-prius-phv-solar-panels/#rCzpfcVjVOqV) that says the Prius solar roof didn’t pass the US safety standards (namely the rollover crash test) and therefore wasn’t offered in the US. I don’t understand how a solar panel is any less safe than sunroofs though. It might affect how a car rolls over–maybe interferes with the roll bar. It does seem like a waste of money. However, solar panels on your house roof–well, that’s another story. We did that three years ago and between what the state of Washington rebated us and savings–huge–on our electric bills, they’ve paid for themselves already. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [June 26, 2019, 3:29pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/59 "2019-06-26T15:29:05Z")
The [Karma electric luxury car](https://www.karmaautomotive.com/revero) has solar panels that claim to “charge the car”. All reviews say that the panels are more of a gimmick than reality, though. It’s a very cool-looking car nevertheless. ---
**Author:** ![Dana\_Scully](https://avatars.discourse-cdn.com/v4/letter/d/5daacb/32.png) [@Dana\_Scully](https://boards.straightdope.com/u/Dana_Scully)\ **Post date:** [June 26, 2019, 3:32pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/60 "2019-06-26T15:32:05Z")
> [@ftg](#): > > Solar trickle chargers and such are a waste for quite a few people. > > For example, us. We park our cars in the garage. And if we were to park in the driveway there’s a big ole maple shading almost all of it. > > While we do make a few short trips here and there and the car will be out in the Sun some, the amount of charge added is going to be insignificant compared to the charge added by the alternator during the trip. We rarely go somewhere and leave a car parked all day. > > And then there’s places like Seattle and Portland for large stretches of the year. 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. Of course in the winter there isn’t as much sun and our bills go up but everything considered, they’ve been a good investment. ---
**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:** [June 26, 2019, 4:01pm UTC](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731/61 "2019-06-26T16:01:37Z")
I would buy one! Great for camping. It produces enough electricity to run a full size washing machine, dryer, dishwasher and microwave every day! This car is the EV equivalent of the Volkswagen [1 liter car](https://en.wikipedia.org/wiki/Volkswagen_1-litre_car). [Previous page](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731.md?page=2) [Next page](https://boards.straightdope.com/t/is-it-feasible-to-put-solar-panels-on-the-roofs-of-cars/821731.md?page=4)