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It's easy to dismiss this as green washing, but there is some value to it for city cars. The amount of electricity generated is never going to be enough to full

It's easy to dismiss this as green washing, but there is some value to it for city cars. The amount of electricity generated is never going to be enough to fully power the car, but that's not really the point. If having solar panels on your car roof means you can avoid charging much in summer, that will make owning an electric car for people who live in cities much simpler - and so support adoption. As a back of the envelope calculation, if you covered the ~2.44 m2 roof of a VW ID3 with solar panels you'd probably see somewhere in the region of 244 kWh / year (based on typical UK solar panel generation per year - this would be more in a sunny place). At 4.3 miles/kWh that gives you just over 1000 miles / year of self charged driving. It's true that those same solar panels would be more productive in a static installation. But it's also the case in the west that the biggest cost to solar rollout is installation, not the panels themselves. Putting panels on the roof of a car can be done in a factory, with none of the tricky site-specific work that makes costs balloon. In fact, Hyundai are already planning a solar roof option with their Ioniq 5 (https://interestingengineering.com/hyundai-unveils-charger-on-wheels-ioniq-5-with-solar-panel-roof https://interestingengineering.com/hyundai-unveils-charger-o...). It will be interesting to see if that has any impact for the typical driver.

kiliantics 6y ago
In a city, since everything is at most a few miles away, one shouldn't need a car to get around. Just put some trams/electric buses and bike lanes around. There, now you've removed about half the cars in the world.
baybal2 6y ago
No, even if you make the half of car surface a solar panel, you would probably not even get a net benefit because of extra weight, and drag from suboptimal hull shape needed to place cells.
- legacynl 6y ago
  Solar panels nowadays don't necessarily weigh that much. Also improved efficiency means that you can get away with following the exisiting body-shape, even if that means decreased power generation. Also you might get away with having less/smaller/lighter batteries if you're able to generate more power yourself.
- jiofih 6y ago
  Did you look at the URL posted at all? The car is in final design stages, has enough cells to deliver 250km of range per week.
  - baybal2 6y ago
    How many kilometres per week they take? 0.05 increase in drag coefficient can alone eat the energy equivalent of 50km in a week.
    - kamranjon 6y ago
      I suspect you still haven't clicked on the link?
      - jiofih 6y ago
        My dream HN feature is only allowing comments after the main link has been visited for 5 minutes.
        Qwertious 6y ago
        Personally I'd like if you could click on the link and then hit the "back" button to go directly to the comments. You can work around by clicking the comments and then the link, but then you look at the top comment and are tempted to read and then respond.
      - baybal2 6y ago
        I did, I read their very optimistic estimates, and I still believe it being near useless with 250km a week.
        jiofih 6y ago
        Your back must hurt from moving that goalpost so often.
    - GrinningFool 6y ago
gt565k 6y ago
Or you could cover every residential building and parking lot's rooftop with solar panels and have charging stations for cars, and low cost electricity for the entire block, neighborhood, and city. This problem of "energy" in particular electricity, can be solved, but requires buy in from millions of different parties (HOAs, building owners, real estate developers). Unless the law changes where you can compel / force these stake-holders to adopt solar panels, change will never come at scale in urban areas. It's possible, it just requires so much buy in from so many individual entities.
- dmos62 6y ago
  Question is whether the panels on the car's roof or on the building's roof can be installed cheaper, and how the installation+maintainance / energy output ratio compares.
  - cptskippy 6y ago
    Don't discount the fact that a car may not have direct sunlight where it's parked, particularly a city car with high buildings surrounding it. I could park a solar panel in my driveway and it wouldn't receive direct sunlight until about 1pm. At 1pm my south facing rooftop solar array is at 97% of peak output, and by 2pm it's down to 82% and falls off pretty sharply after that. At some point in the afternoon the shadow cast from across the street would block that direct sunlight. According to their specs, the car goes 255km on a 35kWh pack which is ~7.286km/Wh. It says it can produce up to 245km of range which is roughly 33.6kWh a week or 4.8kWh a day at best. In my case, it would be closer to half that value at best (2.4kWh), we've been having overcast days and my array has been outputting half it's normal capacity (1.2kWh). That's over 60km of range which would probably work for me but is 1 day's commute for a lot of people.
    - rtkwe 6y ago
      Also I bet the efficiency numbers are for the panel receiving optimal direct sunlight not the high angle light it's going to get because it's on the side of a car nearly vertical.
gnramires 6y ago
Indeed, I were once skeptical (remembering EEVBlog's Solar Roadways series) but it really seems a good deal. Short commutes in cities can probably be covered. And a killer feature to me: if you ever get stranded somewhere without power, you at least have the option to wait a day or two to charge and get to somewhere nearby with power (around 3 miles/day for ioniq, 10 miles/day average for sion according to the articles). Of course, smaller cars will probably have a better surface-energy consumption ratio, I don't expect to make much of a range difference for larger and utility vehicles. It's something I'd add to offroad vehicles just for the cool factor (of independence), even if the range added per day isn't significant in that case.
- samcheng 6y ago
  I'm an electric car driver, and I'm still skeptical. It's hard to imagine a scenario where I accidentally run out of batteries and then can afford to wait for MULTIPLE DAYS before finishing my trip. Pretty sure I'd at least want to get a tow to the nearest gas station, where they would be able to plug me in if necessary. Even a plain old 120V 15A plug has much more power than solar, and works overnight...
  - dmos62 6y ago
    It's not about substituting charging stations. It's about getting _part_ of your energy requirements from the panels. Check the figures in the grandfather comment: energy gains are in the ballpark of 1000 miles / year.
    - Twirrim 6y ago
      > energy gains are in the ballpark of 1000 miles / year That's not a small amount. The US DoT puts average US driving at around 13,500 miles/year. In Germany (Sono Motor's home market) it's 8,000. So we're talking meeting nearly 7.5% of US, and 12.5% of German, average driving needs. Just from sticking a solar panel on the roof of a vehicle.
      - 6y ago
teleforce 6y ago
The Ioniq 5 also come with a Vehicle-to-Load or V2L. This V2L port can charge other electrical appliances including EV cars as well. Since the charging time is very fast for the car itself (16 minutes to 80%), it is very interesting concept that perhaps can enabled Uber like mobile on-demand car charging fleets service that can come to charge EV cars on the road that low on battery [1]. [1]https://electrek.co/2021/03/03/hyundai-ioniq-5-spotted-charging-22-80-in-16-minutes-new-charging-king/ https://electrek.co/2021/03/03/hyundai-ioniq-5-spotted-charg...
yummypaint 6y ago
I agree. I think it's better to think about solar panels on cars in terms of turning parking lots into energy producing area. We already have them and they are mostly wasted space that drive up urban temperatures. Even though the effect on the battery of a single car is small, on a bright day a mall parking lot full of cars is still a significant amount of total energy that doesn't have to come from the grid.
eldaisfish 6y ago
this is nothing but BS. There's so much BS that it's hard to know where to begin. The PV panel power output per square meter is a good place to begin. It's telling that they aren't comparing to standard, off the shelf PV panels which put out over 200 W/m2 as standard. Higher values are commonplace these days. And mind you, that figure of 200 W/m2 is at peak power levels which occur infrequently, often only an hour or two per day at the height of summer. Second, this idea of "charging" ignores a very real issue with cities - shading and latitude. Even if every single car on city streets had PV panels, it is always going to be less technically and financially efficient when compared to rooftop solar which has the benefit of being at a higher elevation and being able to produce more energy. Most cities with the combination of wealth and population required for something like this are not at the equator, they are not even close to the tropics. They are further north. Shading is a bigger problem there as houses of even 5 - 10 m in height cast long shadows. Edit - sad to see that people here will take EV manufacturer's words as gospel and will downvote critical comments. Good luck to anyone purchasing vapourware such as this.
- ben_w 6y ago
  Shade is certainly a consideration, especially given people normally prefer to park their cars in shade to avoid them being unpleasantly hot when they return. Cost, however, isn’t. The cells themselves are extremely cheap compared with the cost of putting them on a rooftop (in the case of homes), and in this case replaces the use of paint on the bodywork. Specifically, the cost of cells is now down to ~$0.30/W, so 5 m^2 [0] of 200 W/m^2 would cost about $300. Similar arguments exist for PV roofing tiles being replacements for ceramic etc. tiles rather than the common sight of bulky window-size sheets attached after construction. The claimed average range boost of 112 km/week (~3600 miles per year) in “average” conditions, and ~7900 miles per year in optimal conditions, definitely sounds about right to me based both on discussions last time a completely different PV consumer car was discussed here and on my BOTE calculations. Is that range worth $300 extra on the purchase price? Perhaps; it would pay for itself after ~1.88 years. Doesn’t guarantee this isn’t vapourware (thinking of recent news about Nikola Corporation), but it is at least plausible. [0] I am guesstimating the area
  - 6y ago
40four 6y ago
This topic came up on the recent Joe Rogan with Elon Musk. Elon said they considered it, but in the end it is just not worth it. He said there is just not enough surface area on a car to contribute a worthwhile amount of electricity. The numbers quoted for this particular vehicle are very optimistic I think. If you’re lucky, you might get 5 miles a day out of it. What happens if it’s cloudy or rainy for a week? Or you park in a garage? There are so many variables, and the return on investment will be highly variable. Tesla decided it’s just not worth the extra cost and complexity, for such a small return. I agree the idea sounds nice, but I’m afraid these companies that are doing are this, are mostly just getting a nice PR boost. There is just no way around the technical limitations of solar panels in the amount of energy they can convert, and the surface area of a car. Vans or RVs that could fold out a larger array when parked might be another story. I will say, it looks like they have some real innovations in the design and engineering of integrating the panels in the body. Looks pretty cool, so that’s not nothing:)
- agumonkey 6y ago
  He didn't mention the semi ? The large flat area, long time under the sun, difference of market (no need to integrate it pretty, a simple flatbed on top would do)
  - mbreese 6y ago
    Semi trucks and trailers are two different components. Most trailers have a large flat area, but these can get swapped often. And even within the same company you won’t always have the solar trailer hooked up to the electric semi. The swappable nature of the load is part of the appeal of semis. I guess what I’m saying is, even if you had a solar trailer, you would lose a lot of the load flexibility of using a semi truck. And you wouldn’t want to plan a load where you needed the solar power. So either way, you’re planning for charging at fixed intervals. Solar might help a little here, but not very much.
    - RandallBrown 6y ago
      Couldn't it make the cost of shipping cheaper if the the load is able to contribute some energy to the truck? You'd need some sort of standard for the trailer to provide electricity to a hybrid/electric truck but ignoring that (major) issue it seems like a pretty great idea.
agumonkey 6y ago
And this is considering a car not made for this. A longer or van like model would have more surface. I often wonder if slow small buses wouldn't be possible on solar.
- puetzk 6y ago
  If you want to look at the limits of what physics seems to allow (cost practicality be damned), look at things like americansolarchallenge.org winners. They even have a multi-occupant-vehicle class nowadays. The 2018 MOV winner (https://www.americansolarchallenge.org/the-competition/american-solar-challenge-2018/ https://www.americansolarchallenge.org/the-competition/ameri... ) logged 1762 miles over 58.4 hours, or about 30mph average pace (with a 16.8kWh battery, but no external charging, just the ability to time-shift some energy). That's with a vehicle that looks like this: https://www.youtube.com/watch?v=aE9gkYsR4TU https://www.youtube.com/watch?v=aE9gkYsR4TU
  - agumonkey 6y ago
    late reply, but thanks a lot for this
mikestew 6y ago
If having solar panels on your car roof means you can avoid charging much in summer Some variation of this comes up every time: “but even a little bit helps” without knowing how little it is. I’ve got a Nissan Leaf. I’ve also got an RV with 400W of solar on top. That’s enough solar to keep things running all day on a reasonably sunny day. Unless you want to run the 1100W microwave, which you can run for fifteen or twenty minutes before you get to start over. Or you could drive an electric car for five minutes. All this “doing the math” assumes perfect efficiency, blah, blah, to barely come out making it maybe kinda worth it. In the real world of cloudy days and off-angle sunlight, you’re better off having a sun roof put in and charging off your home’s solar panel. Or to put it more bluntly, until solar panel efficiency goes way up, panels on top of the vehicle is just dumb.
justapassenger 6y ago
You need to at least half, but most likely more, your estimate if you talk about cars that live in the cities. For solar panels efficiency, two main things that matter are proper angle to the sun and amount of shade. Parking in the city, you cannot choose to align your panels with a sun. And you’ll be surrounded by tall structures (buildings, trees, etc) that will shade your car. You’ll get nowhere near close to an efficiency of a house rooftop solar.
labcomputer 6y ago
> As a back of the envelope calculation, if you covered the ~2.44 m2 roof of a VW ID3 with solar panels you'd probably see somewhere in the region of 244 kWh / year (based on typical UK solar panel generation per year - this would be more in a sunny place). Only 244 kWh/year?!? You'd get the same amount of energy by plugging in to a basic 120V North American household plug every weeknight (you don't even need to charge on weekends!). Or 30 minutes per weeknight by plugging in to a basic UK household plug. Or you could just leave it plugged in to a household outlet overnight once per week.
dwighttk 6y ago
> If having solar panels on your car roof means you can avoid charging much in summer You seem to be aware that this is not the case but also not so much... can’t tell what your comment is trying to support.
scsilver 6y ago
I see solar roofs all the time on camper vans out here, I think the combo of smart ev trailer for out west living is becoming such a value proposition. Especially if I can use leverage some of the car/trailer mounted solar for reducing my electric demands. I wonder when we will start seeing solar power plants/mobile home combos.
hansel_der 6y ago
agree this feature is mindlessly put down. myself and lot of ppl i know would be very interested in a car that basically charges itself when used only a couple times a week for short trips. not for the electricy cost but mainly for the convenience.

kiliantics 6y ago

In a city, since everything is at most a few miles away, one shouldn't need a car to get around. Just put some trams/electric buses and bike lanes around. There, now you've removed about half the cars in the world.

baybal2 6y ago

No, even if you make the half of car surface a solar panel, you would probably not even get a net benefit because of extra weight, and drag from suboptimal hull shape needed to place cells.

legacynl 6y ago
Solar panels nowadays don't necessarily weigh that much. Also improved efficiency means that you can get away with following the exisiting body-shape, even if that means decreased power generation. Also you might get away with having less/smaller/lighter batteries if you're able to generate more power yourself.
jiofih 6y ago
Did you look at the URL posted at all? The car is in final design stages, has enough cells to deliver 250km of range per week.
- baybal2 6y ago
  How many kilometres per week they take? 0.05 increase in drag coefficient can alone eat the energy equivalent of 50km in a week.
  - kamranjon 6y ago
    I suspect you still haven't clicked on the link?
    - jiofih 6y ago
      My dream HN feature is only allowing comments after the main link has been visited for 5 minutes.
      - Qwertious 6y ago
        Personally I'd like if you could click on the link and then hit the "back" button to go directly to the comments. You can work around by clicking the comments and then the link, but then you look at the top comment and are tempted to read and then respond.
    - baybal2 6y ago
      I did, I read their very optimistic estimates, and I still believe it being near useless with 250km a week.
      - jiofih 6y ago
        Your back must hurt from moving that goalpost so often.
  - GrinningFool 6y ago

gt565k 6y ago

Or you could cover every residential building and parking lot's rooftop with solar panels and have charging stations for cars, and low cost electricity for the entire block, neighborhood, and city. This problem of "energy" in particular electricity, can be solved, but requires buy in from millions of different parties (HOAs, building owners, real estate developers). Unless the law changes where you can compel / force these stake-holders to adopt solar panels, change will never come at scale in urban areas. It's possible, it just requires so much buy in from so many individual entities.

dmos62 6y ago
Question is whether the panels on the car's roof or on the building's roof can be installed cheaper, and how the installation+maintainance / energy output ratio compares.
- cptskippy 6y ago
  Don't discount the fact that a car may not have direct sunlight where it's parked, particularly a city car with high buildings surrounding it. I could park a solar panel in my driveway and it wouldn't receive direct sunlight until about 1pm. At 1pm my south facing rooftop solar array is at 97% of peak output, and by 2pm it's down to 82% and falls off pretty sharply after that. At some point in the afternoon the shadow cast from across the street would block that direct sunlight. According to their specs, the car goes 255km on a 35kWh pack which is ~7.286km/Wh. It says it can produce up to 245km of range which is roughly 33.6kWh a week or 4.8kWh a day at best. In my case, it would be closer to half that value at best (2.4kWh), we've been having overcast days and my array has been outputting half it's normal capacity (1.2kWh). That's over 60km of range which would probably work for me but is 1 day's commute for a lot of people.
  - rtkwe 6y ago
    Also I bet the efficiency numbers are for the panel receiving optimal direct sunlight not the high angle light it's going to get because it's on the side of a car nearly vertical.

gnramires 6y ago

Indeed, I were once skeptical (remembering EEVBlog's Solar Roadways series) but it really seems a good deal. Short commutes in cities can probably be covered. And a killer feature to me: if you ever get stranded somewhere without power, you at least have the option to wait a day or two to charge and get to somewhere nearby with power (around 3 miles/day for ioniq, 10 miles/day average for sion according to the articles). Of course, smaller cars will probably have a better surface-energy consumption ratio, I don't expect to make much of a range difference for larger and utility vehicles. It's something I'd add to offroad vehicles just for the cool factor (of independence), even if the range added per day isn't significant in that case.

samcheng 6y ago
I'm an electric car driver, and I'm still skeptical. It's hard to imagine a scenario where I accidentally run out of batteries and then can afford to wait for MULTIPLE DAYS before finishing my trip. Pretty sure I'd at least want to get a tow to the nearest gas station, where they would be able to plug me in if necessary. Even a plain old 120V 15A plug has much more power than solar, and works overnight...
- dmos62 6y ago
  It's not about substituting charging stations. It's about getting _part_ of your energy requirements from the panels. Check the figures in the grandfather comment: energy gains are in the ballpark of 1000 miles / year.
  - Twirrim 6y ago
    > energy gains are in the ballpark of 1000 miles / year That's not a small amount. The US DoT puts average US driving at around 13,500 miles/year. In Germany (Sono Motor's home market) it's 8,000. So we're talking meeting nearly 7.5% of US, and 12.5% of German, average driving needs. Just from sticking a solar panel on the roof of a vehicle.
    - 6y ago

teleforce 6y ago

The Ioniq 5 also come with a Vehicle-to-Load or V2L. This V2L port can charge other electrical appliances including EV cars as well. Since the charging time is very fast for the car itself (16 minutes to 80%), it is very interesting concept that perhaps can enabled Uber like mobile on-demand car charging fleets service that can come to charge EV cars on the road that low on battery [1]. [1]https://electrek.co/2021/03/03/hyundai-ioniq-5-spotted-charging-22-80-in-16-minutes-new-charging-king/ https://electrek.co/2021/03/03/hyundai-ioniq-5-spotted-charg...

yummypaint 6y ago

I agree. I think it's better to think about solar panels on cars in terms of turning parking lots into energy producing area. We already have them and they are mostly wasted space that drive up urban temperatures. Even though the effect on the battery of a single car is small, on a bright day a mall parking lot full of cars is still a significant amount of total energy that doesn't have to come from the grid.

eldaisfish 6y ago

this is nothing but BS. There's so much BS that it's hard to know where to begin. The PV panel power output per square meter is a good place to begin. It's telling that they aren't comparing to standard, off the shelf PV panels which put out over 200 W/m2 as standard. Higher values are commonplace these days. And mind you, that figure of 200 W/m2 is at peak power levels which occur infrequently, often only an hour or two per day at the height of summer. Second, this idea of "charging" ignores a very real issue with cities - shading and latitude. Even if every single car on city streets had PV panels, it is always going to be less technically and financially efficient when compared to rooftop solar which has the benefit of being at a higher elevation and being able to produce more energy. Most cities with the combination of wealth and population required for something like this are not at the equator, they are not even close to the tropics. They are further north. Shading is a bigger problem there as houses of even 5 - 10 m in height cast long shadows. Edit - sad to see that people here will take EV manufacturer's words as gospel and will downvote critical comments. Good luck to anyone purchasing vapourware such as this.

ben_w 6y ago
Shade is certainly a consideration, especially given people normally prefer to park their cars in shade to avoid them being unpleasantly hot when they return. Cost, however, isn’t. The cells themselves are extremely cheap compared with the cost of putting them on a rooftop (in the case of homes), and in this case replaces the use of paint on the bodywork. Specifically, the cost of cells is now down to ~$0.30/W, so 5 m^2 [0] of 200 W/m^2 would cost about $300. Similar arguments exist for PV roofing tiles being replacements for ceramic etc. tiles rather than the common sight of bulky window-size sheets attached after construction. The claimed average range boost of 112 km/week (~3600 miles per year) in “average” conditions, and ~7900 miles per year in optimal conditions, definitely sounds about right to me based both on discussions last time a completely different PV consumer car was discussed here and on my BOTE calculations. Is that range worth $300 extra on the purchase price? Perhaps; it would pay for itself after ~1.88 years. Doesn’t guarantee this isn’t vapourware (thinking of recent news about Nikola Corporation), but it is at least plausible. [0] I am guesstimating the area
- 6y ago

40four 6y ago

This topic came up on the recent Joe Rogan with Elon Musk. Elon said they considered it, but in the end it is just not worth it. He said there is just not enough surface area on a car to contribute a worthwhile amount of electricity. The numbers quoted for this particular vehicle are very optimistic I think. If you’re lucky, you might get 5 miles a day out of it. What happens if it’s cloudy or rainy for a week? Or you park in a garage? There are so many variables, and the return on investment will be highly variable. Tesla decided it’s just not worth the extra cost and complexity, for such a small return. I agree the idea sounds nice, but I’m afraid these companies that are doing are this, are mostly just getting a nice PR boost. There is just no way around the technical limitations of solar panels in the amount of energy they can convert, and the surface area of a car. Vans or RVs that could fold out a larger array when parked might be another story. I will say, it looks like they have some real innovations in the design and engineering of integrating the panels in the body. Looks pretty cool, so that’s not nothing:)

agumonkey 6y ago
He didn't mention the semi ? The large flat area, long time under the sun, difference of market (no need to integrate it pretty, a simple flatbed on top would do)
- mbreese 6y ago
  Semi trucks and trailers are two different components. Most trailers have a large flat area, but these can get swapped often. And even within the same company you won’t always have the solar trailer hooked up to the electric semi. The swappable nature of the load is part of the appeal of semis. I guess what I’m saying is, even if you had a solar trailer, you would lose a lot of the load flexibility of using a semi truck. And you wouldn’t want to plan a load where you needed the solar power. So either way, you’re planning for charging at fixed intervals. Solar might help a little here, but not very much.
  - RandallBrown 6y ago
    Couldn't it make the cost of shipping cheaper if the the load is able to contribute some energy to the truck? You'd need some sort of standard for the trailer to provide electricity to a hybrid/electric truck but ignoring that (major) issue it seems like a pretty great idea.

agumonkey 6y ago

And this is considering a car not made for this. A longer or van like model would have more surface. I often wonder if slow small buses wouldn't be possible on solar.

puetzk 6y ago
If you want to look at the limits of what physics seems to allow (cost practicality be damned), look at things like americansolarchallenge.org winners. They even have a multi-occupant-vehicle class nowadays. The 2018 MOV winner (https://www.americansolarchallenge.org/the-competition/american-solar-challenge-2018/ https://www.americansolarchallenge.org/the-competition/ameri... ) logged 1762 miles over 58.4 hours, or about 30mph average pace (with a 16.8kWh battery, but no external charging, just the ability to time-shift some energy). That's with a vehicle that looks like this: https://www.youtube.com/watch?v=aE9gkYsR4TU https://www.youtube.com/watch?v=aE9gkYsR4TU
- agumonkey 6y ago
  late reply, but thanks a lot for this

mikestew 6y ago

If having solar panels on your car roof means you can avoid charging much in summer Some variation of this comes up every time: “but even a little bit helps” without knowing how little it is. I’ve got a Nissan Leaf. I’ve also got an RV with 400W of solar on top. That’s enough solar to keep things running all day on a reasonably sunny day. Unless you want to run the 1100W microwave, which you can run for fifteen or twenty minutes before you get to start over. Or you could drive an electric car for five minutes. All this “doing the math” assumes perfect efficiency, blah, blah, to barely come out making it maybe kinda worth it. In the real world of cloudy days and off-angle sunlight, you’re better off having a sun roof put in and charging off your home’s solar panel. Or to put it more bluntly, until solar panel efficiency goes way up, panels on top of the vehicle is just dumb.

justapassenger 6y ago

You need to at least half, but most likely more, your estimate if you talk about cars that live in the cities. For solar panels efficiency, two main things that matter are proper angle to the sun and amount of shade. Parking in the city, you cannot choose to align your panels with a sun. And you’ll be surrounded by tall structures (buildings, trees, etc) that will shade your car. You’ll get nowhere near close to an efficiency of a house rooftop solar.

labcomputer 6y ago

> As a back of the envelope calculation, if you covered the ~2.44 m2 roof of a VW ID3 with solar panels you'd probably see somewhere in the region of 244 kWh / year (based on typical UK solar panel generation per year - this would be more in a sunny place). Only 244 kWh/year?!? You'd get the same amount of energy by plugging in to a basic 120V North American household plug every weeknight (you don't even need to charge on weekends!). Or 30 minutes per weeknight by plugging in to a basic UK household plug. Or you could just leave it plugged in to a household outlet overnight once per week.

dwighttk 6y ago

> If having solar panels on your car roof means you can avoid charging much in summer You seem to be aware that this is not the case but also not so much... can’t tell what your comment is trying to support.

scsilver 6y ago

I see solar roofs all the time on camper vans out here, I think the combo of smart ev trailer for out west living is becoming such a value proposition. Especially if I can use leverage some of the car/trailer mounted solar for reducing my electric demands. I wonder when we will start seeing solar power plants/mobile home combos.

hansel_der 6y ago

agree this feature is mindlessly put down. myself and lot of ppl i know would be very interested in a car that basically charges itself when used only a couple times a week for short trips. not for the electricy cost but mainly for the convenience.