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Might be a noob question, but why can't EVs have solar panels on them directly so they can get charged just by moving around? Or why can't we have SVs(Solar Veh

Might be a noob question, but why can't EVs have solar panels on them directly so they can get charged just by moving around? Or why can't we have SVs(Solar Vehicles)? Why do we have to use solar panels on EV stations rather than just having them on the vehicles themselves?

arjonagelhout 6mo ago
There was a production car planned called the Lightyear One [0], originating from a Dutch student team, but if I recall correctly it was quite difficult and expensive to manufacture. [0] https://en.wikipedia.org/wiki/Lightyear_0 https://en.wikipedia.org/wiki/Lightyear_0
- embedding-shape 6mo ago
  > but if I recall correctly it was quite difficult and expensive to manufacture More importantly, seems they stopped manufacture it because they made a new version, that was supposed to be available in 2025, but I don't think I've seen it anywhere. > However, in January 2023 Lightyear announced that it was halting production of the 0 model, redirecting their efforts towards production of Lightyear 2; Atlas Technologies B.V., the subsidiary responsible for the manufacture of the Lightyear 0, would be allowed to go bankrupt. As of 2023, the replacement, Lightyear 2, is slated to be US$40,000 and available in both Europe and North America, and to start production in 2025.
defrost 6mo ago
You absolutely can .. but in order to be self sustaining vehicles need to look somewhat like the builds that appear in Australian multi day solar races - ultra lightweight, extreme streamlining, zero driver comfort, no extras like cargo space and automatic rear doors, etc. Maybe in time efficiencies will get there. * https://worldsolarchallenge.org/ https://worldsolarchallenge.org/ * https://www.youtube.com/watch?v=4K0FD9Hh6XY https://www.youtube.com/watch?v=4K0FD9Hh6XY * https://www.youtube.com/watch?v=R_lVdrHnbYo https://www.youtube.com/watch?v=R_lVdrHnbYo Addendum: addressing the [dead] comment below > With 100% efficiency the area of the car is too small to produce enough electricity to drive. is false - Australia has been racing solar powered cars for a good many years now, clearly they generate sufficient power to drive, just not especially fast, with any reserve energy, or at night, with any real comfort, etc.
- szundi 6mo ago
  [dead]
- embedding-shape 6mo ago
  Ok, so lets say we didn't want 100% of the energy to come from those "self-sustainable panels on the car", but rather N%, so we keep most everything as-is, except switching all the outside body/chassi panels for solar panels, how much N% could we recover from that? Could it change so someone goes from needing to charge once every 3 days to once every 2 weeks lets say? Together with re-generative breaking, maybe it could at least have some impact.
  - thechao 6mo ago
    You're off by an order of magnitude. It's a few hundred watts; an EV is consuming 10s of kilowatts. (Ignore the watt-watt/hour sloppiness, pls.) To charge my car 60% would take about 2 months. Ambient needs (battery cooling) would eat up more than I'd get back. At best it extends idle sit time.
    - embedding-shape 6mo ago
      > You're off by an order of magnitude. How can a question be "off"? :D I literally used N% as to avoid replies like this, but seems you managed anyways... > To charge my car 60% would take about 2 months. Depends heavily on where you park and where in the world you live, wouldn't it? I use my car maybe 2-3 hours per week, most of the time it's just standing outside in sunny Spain, would that change the calculation anything?
- functional_dev 6mo ago
  consumer car needs hundreds of pounds of reinforcement... just to pass side impact test
snowchaser 6mo ago
It’s a good question, but the reality is the energy required to power a car is far larger than what you can collect. The solar energy you can collect is about 750W/sq meter. A car roof is about 5’x5’, and if we are generous and include a trunk and hood area, maybe you are getting 60 sqft? Best case if the sun is right over the car you can illuminate about 5 square meters. That’s about 3.75KW. To convert that to a more familiar car power measurement that’s about 5 horsepower. Hopefully it’s clear why a realtime solar car is hard. This is not to say it’s impossible, they have been built. They’re just not super practical for everyday use. https://en.wikipedia.org/wiki/Solar_car https://en.wikipedia.org/wiki/Solar_car
- Jedd 6mo ago
  > The solar energy you can collect is about 750W/sq meter. > A car roof is about 5’x5’, and if we are generous and include a trunk and hood area, maybe you are getting 60 sqft? We must think metric, every inch of the way! Anyway, PVCs currently max out at about 300W / square metre - and that's in ideal conditions. I believe theoretical maximum energy per square metre (when light actually arrives at the planet surface) is conveniently pretty close to 1000W, assuming you're in the right place, but maximum efficiency of contemporary panels is only about 30%.
  - snowchaser 6mo ago
    Totally agree, SI units for the win! I was just trying to use “familiar” units. I could have led with 1 HP per square yard, and then you’d totally have license to call me out! And yeah, I was just talking about solar flux, there’s a whole lot of real world losses to consider but my point was that none of this matters, it’s orders of magnitude away from ICE engine output.
    - Jedd 6mo ago
      It was the fact you started using units the world knows - albeit misspelling metre - but in the next sentence, comparing that same dimension, you used an apostrophe to allude to a unit that only 5% of the planet uses.
thinkcontext 6mo ago
The amount of power that can be generated from the surface area of a car is pretty small compared to how much a car consumes. And the cost hasn't been low enough compared to the value of the electricity it could produce. Maybe someday the price will get so low it will be a no-brainer.
- SideburnsOfDoom 6mo ago
  > Maybe someday the price will get so low it will be a no-brainer. The cost of solar panels is already low, that's why it's booming. This cost isn't the main constraint any more. Panels on a vehicle have stronger requirements for low weight, and vibration tolerance than those on a fixed structure. They contribute to the complexity of the vehicle's power systems. They have to be designed with vehicle aerodynamics in mind. And of course the limited surface area means that you do all of that, for a component that's it's barely able to keep the vehicles' aircon running. The physics of that will remain the same. Even of the total costs are low (and factors such as the vehicle weighing more are an unavoidable cost), the benefits are lower. At any price point, including free solar panels, there are good arguments to put the panels on a fixed structure instead. So maybe it will happen when we have run out of non-moving surfaces to put the panels on. i.e. don't hold your breath.
Moldoteck 6mo ago
you get too little energy vs the cost of integrating it. It gets worse considering as a driver you want to park your car in shade/garage/multistory parkings
SideburnsOfDoom 6mo ago
> Might be a noob question, but why can't EVs have solar panels on them directly This is 100% a very common noob question. The answers are therefor easy to find if you try. https://www.forbes.com/sites/billroberson/2022/11/30/why-doesnt-every-electric-car-have-solar-panels/ https://www.forbes.com/sites/billroberson/2022/11/30/why-doe... https://octopusev.com/ev-hub/why-dont-electric-cars-have-solar-panels https://octopusev.com/ev-hub/why-dont-electric-cars-have-sol... https://www.youtube.com/watch?v=7L1_zvqg73Q&t=590s https://www.youtube.com/watch?v=7L1_zvqg73Q&t=590s A much better idea is to 20x the surface area of solar panels, get ones that aren't as weight sensitive (and therefor expensive), mount them on your house or garage roof instead, and charge the EV off that when it's parked adjacent. Maybe add a battery as buffer for when the car's not there. And it in fact has been an option on some cars, but not a popular one. It has been described as "worthless" https://www.reddit.com/r/Hyundai/comments/tayavo/what_happened_to_the_solar_roof_on_the_ioniq_5/ https://www.reddit.com/r/Hyundai/comments/tayavo/what_happen... https://news.ycombinator.com/item?id=46456963 https://news.ycombinator.com/item?id=46456963 Have a look at this, which is a (semi) serious hacker attempt to make it a bit more practical. https://www.dartsolar.com/ https://www.dartsolar.com/ https://www.reddit.com/r/TeslaLounge/comments/194ajsm/my_tesla_with_a_drivable_2000_to_4000_solar_array/ https://www.reddit.com/r/TeslaLounge/comments/194ajsm/my_tes... He came up with a design where the panels can can unfolded for a larger surface area. But you can only do that when the car is at rest. And it's permanently like having a loaded roof-rack. Its's still less practical than mounting solar panels on the roof of a house or other fixed structure.
nirolo 6mo ago
Aptera has this planned but not sure if they ever reach market maturity. There also was a project car from the Nordics I think. Can't recall the name though. Main problem is the large amount of energy a car needs vs what kind of surface area you have and efficiency we get. An ideal (100% effiwncy) solar cell of 5m² would still need 20 hours to charge a 100kWh battery. And we are way off on area an efficiency in reality.
- amunozo 6mo ago
  Well but that would be a problem for keeping the car infinitely running with only solar power. But what about just passively charging it while idle? Cars sit idle most of the time.
- SideburnsOfDoom 6mo ago
  > Aptera has this planned but not sure if they ever reach market maturity. Yes, Aptera does not have a shipping product, and if they ship the current design it might not have a large market for it. The have been promising delivery for a long time now, so it certainly looks a lot like vapourware.
GoToRO 6mo ago
My understanding is that when buying a car you are dealing with an oligopoly. You might think that you have a lot of options, but they all come from the same source. Furthermore, big money control not only car production, but oil too. If they allow the ceo of a car company to come with such a car, they loose billions in the oil industry. So they have no incentive to do that. New options do appear on the market like the new toyota prius with solar panel, but if you look at it you will see that they didn't even try to maximize the solar panel size. Still it gets 2 km extra range in bad conditions. Triple that and you have 6 km, in real conditions. If you use your car every other day, you will never charge it, ever. If you get average or above sun, you can drive it daily and not charge it ever. A big problem if you sell oil. The problem with green energy is that it is very democratic and hard to control. Nobody with big money is interested in that. To understand who controls your life, see all the draconian measures taken against electric scooters: cheap, not poluting, democratic, don't need a lot of space and so on. Everyone with money said: we can't allow that. Write defamatory articles in the media they control, pass laws against it and so on.
- SideburnsOfDoom 6mo ago
  > The problem with green energy is that it is very democratic and hard to control. It's not that I totally disagree with this - there is some truth to it. But it has no bearing at all on the question "can I put the panels on the car instead?" Which has been debunked in this thread and elsewhere many, many times. The counterargument to what you say is that Solar is in fact booming. It is coming - oil money can slow it, but not stop it. They have more success in some countries than others. It's not a coincidence that China, which course desires energy independence but doesn't have access to a lot of oil, is leading the way. Sorry USA, you're laggards now. But solar + battery is on an exponential ramp-up and getting big now. Each shock like the current Hormoz idiocy makes the case for it even more to the rest of the world. It's coming, fast. Just, it's not useful on car roofs. That's a poor choice of panel location.
  - bryanlarsen 6mo ago
    > China doesn't have access to a lot of oil Just an aside, but China is the 5th largest oil producer. They have a lot of oil. The problem is that they're the 2nd largest oil consumer, so are still importing. Their current course is sufficient to achieve energy independence. It's kind of unfortunate they don't need to further decarbonize to achieve that independence. There are some other fields that aren't yet economically valid to decarbonize. If China had a non-economic reason to decarbonize jet fuel, steel, plastic etc they might drive enough volume to make them economic.
shepherdjerred 6mo ago
Hyundai had this https://techcrunch.com/2022/03/23/hyundai-sonata-hybrid-roof/ https://techcrunch.com/2022/03/23/hyundai-sonata-hybrid-roof... > After baking in the sun all day, the car can add 3-4 miles to its range.

arjonagelhout 6mo ago

There was a production car planned called the Lightyear One [0], originating from a Dutch student team, but if I recall correctly it was quite difficult and expensive to manufacture. [0] https://en.wikipedia.org/wiki/Lightyear_0 https://en.wikipedia.org/wiki/Lightyear_0

embedding-shape 6mo ago
> but if I recall correctly it was quite difficult and expensive to manufacture More importantly, seems they stopped manufacture it because they made a new version, that was supposed to be available in 2025, but I don't think I've seen it anywhere. > However, in January 2023 Lightyear announced that it was halting production of the 0 model, redirecting their efforts towards production of Lightyear 2; Atlas Technologies B.V., the subsidiary responsible for the manufacture of the Lightyear 0, would be allowed to go bankrupt. As of 2023, the replacement, Lightyear 2, is slated to be US$40,000 and available in both Europe and North America, and to start production in 2025.

defrost 6mo ago

You absolutely can .. but in order to be self sustaining vehicles need to look somewhat like the builds that appear in Australian multi day solar races - ultra lightweight, extreme streamlining, zero driver comfort, no extras like cargo space and automatic rear doors, etc. Maybe in time efficiencies will get there. * https://worldsolarchallenge.org/ https://worldsolarchallenge.org/ * https://www.youtube.com/watch?v=4K0FD9Hh6XY https://www.youtube.com/watch?v=4K0FD9Hh6XY * https://www.youtube.com/watch?v=R_lVdrHnbYo https://www.youtube.com/watch?v=R_lVdrHnbYo Addendum: addressing the [dead] comment below > With 100% efficiency the area of the car is too small to produce enough electricity to drive. is false - Australia has been racing solar powered cars for a good many years now, clearly they generate sufficient power to drive, just not especially fast, with any reserve energy, or at night, with any real comfort, etc.

szundi 6mo ago
[dead]
embedding-shape 6mo ago
Ok, so lets say we didn't want 100% of the energy to come from those "self-sustainable panels on the car", but rather N%, so we keep most everything as-is, except switching all the outside body/chassi panels for solar panels, how much N% could we recover from that? Could it change so someone goes from needing to charge once every 3 days to once every 2 weeks lets say? Together with re-generative breaking, maybe it could at least have some impact.
- thechao 6mo ago
  You're off by an order of magnitude. It's a few hundred watts; an EV is consuming 10s of kilowatts. (Ignore the watt-watt/hour sloppiness, pls.) To charge my car 60% would take about 2 months. Ambient needs (battery cooling) would eat up more than I'd get back. At best it extends idle sit time.
  - embedding-shape 6mo ago
    > You're off by an order of magnitude. How can a question be "off"? :D I literally used N% as to avoid replies like this, but seems you managed anyways... > To charge my car 60% would take about 2 months. Depends heavily on where you park and where in the world you live, wouldn't it? I use my car maybe 2-3 hours per week, most of the time it's just standing outside in sunny Spain, would that change the calculation anything?
functional_dev 6mo ago
consumer car needs hundreds of pounds of reinforcement... just to pass side impact test

snowchaser 6mo ago

It’s a good question, but the reality is the energy required to power a car is far larger than what you can collect. The solar energy you can collect is about 750W/sq meter. A car roof is about 5’x5’, and if we are generous and include a trunk and hood area, maybe you are getting 60 sqft? Best case if the sun is right over the car you can illuminate about 5 square meters. That’s about 3.75KW. To convert that to a more familiar car power measurement that’s about 5 horsepower. Hopefully it’s clear why a realtime solar car is hard. This is not to say it’s impossible, they have been built. They’re just not super practical for everyday use. https://en.wikipedia.org/wiki/Solar_car https://en.wikipedia.org/wiki/Solar_car

Jedd 6mo ago
> The solar energy you can collect is about 750W/sq meter. > A car roof is about 5’x5’, and if we are generous and include a trunk and hood area, maybe you are getting 60 sqft? We must think metric, every inch of the way! Anyway, PVCs currently max out at about 300W / square metre - and that's in ideal conditions. I believe theoretical maximum energy per square metre (when light actually arrives at the planet surface) is conveniently pretty close to 1000W, assuming you're in the right place, but maximum efficiency of contemporary panels is only about 30%.
- snowchaser 6mo ago
  Totally agree, SI units for the win! I was just trying to use “familiar” units. I could have led with 1 HP per square yard, and then you’d totally have license to call me out! And yeah, I was just talking about solar flux, there’s a whole lot of real world losses to consider but my point was that none of this matters, it’s orders of magnitude away from ICE engine output.
  - Jedd 6mo ago
    It was the fact you started using units the world knows - albeit misspelling metre - but in the next sentence, comparing that same dimension, you used an apostrophe to allude to a unit that only 5% of the planet uses.

thinkcontext 6mo ago

The amount of power that can be generated from the surface area of a car is pretty small compared to how much a car consumes. And the cost hasn't been low enough compared to the value of the electricity it could produce. Maybe someday the price will get so low it will be a no-brainer.

SideburnsOfDoom 6mo ago
> Maybe someday the price will get so low it will be a no-brainer. The cost of solar panels is already low, that's why it's booming. This cost isn't the main constraint any more. Panels on a vehicle have stronger requirements for low weight, and vibration tolerance than those on a fixed structure. They contribute to the complexity of the vehicle's power systems. They have to be designed with vehicle aerodynamics in mind. And of course the limited surface area means that you do all of that, for a component that's it's barely able to keep the vehicles' aircon running. The physics of that will remain the same. Even of the total costs are low (and factors such as the vehicle weighing more are an unavoidable cost), the benefits are lower. At any price point, including free solar panels, there are good arguments to put the panels on a fixed structure instead. So maybe it will happen when we have run out of non-moving surfaces to put the panels on. i.e. don't hold your breath.

Moldoteck 6mo ago

you get too little energy vs the cost of integrating it. It gets worse considering as a driver you want to park your car in shade/garage/multistory parkings

SideburnsOfDoom 6mo ago

> Might be a noob question, but why can't EVs have solar panels on them directly This is 100% a very common noob question. The answers are therefor easy to find if you try. https://www.forbes.com/sites/billroberson/2022/11/30/why-doesnt-every-electric-car-have-solar-panels/ https://www.forbes.com/sites/billroberson/2022/11/30/why-doe... https://octopusev.com/ev-hub/why-dont-electric-cars-have-solar-panels https://octopusev.com/ev-hub/why-dont-electric-cars-have-sol... https://www.youtube.com/watch?v=7L1_zvqg73Q&t=590s https://www.youtube.com/watch?v=7L1_zvqg73Q&t=590s A much better idea is to 20x the surface area of solar panels, get ones that aren't as weight sensitive (and therefor expensive), mount them on your house or garage roof instead, and charge the EV off that when it's parked adjacent. Maybe add a battery as buffer for when the car's not there. And it in fact has been an option on some cars, but not a popular one. It has been described as "worthless" https://www.reddit.com/r/Hyundai/comments/tayavo/what_happened_to_the_solar_roof_on_the_ioniq_5/ https://www.reddit.com/r/Hyundai/comments/tayavo/what_happen... https://news.ycombinator.com/item?id=46456963 https://news.ycombinator.com/item?id=46456963 Have a look at this, which is a (semi) serious hacker attempt to make it a bit more practical. https://www.dartsolar.com/ https://www.dartsolar.com/ https://www.reddit.com/r/TeslaLounge/comments/194ajsm/my_tesla_with_a_drivable_2000_to_4000_solar_array/ https://www.reddit.com/r/TeslaLounge/comments/194ajsm/my_tes... He came up with a design where the panels can can unfolded for a larger surface area. But you can only do that when the car is at rest. And it's permanently like having a loaded roof-rack. Its's still less practical than mounting solar panels on the roof of a house or other fixed structure.

nirolo 6mo ago

Aptera has this planned but not sure if they ever reach market maturity. There also was a project car from the Nordics I think. Can't recall the name though. Main problem is the large amount of energy a car needs vs what kind of surface area you have and efficiency we get. An ideal (100% effiwncy) solar cell of 5m² would still need 20 hours to charge a 100kWh battery. And we are way off on area an efficiency in reality.

amunozo 6mo ago
Well but that would be a problem for keeping the car infinitely running with only solar power. But what about just passively charging it while idle? Cars sit idle most of the time.
SideburnsOfDoom 6mo ago
> Aptera has this planned but not sure if they ever reach market maturity. Yes, Aptera does not have a shipping product, and if they ship the current design it might not have a large market for it. The have been promising delivery for a long time now, so it certainly looks a lot like vapourware.

GoToRO 6mo ago

My understanding is that when buying a car you are dealing with an oligopoly. You might think that you have a lot of options, but they all come from the same source. Furthermore, big money control not only car production, but oil too. If they allow the ceo of a car company to come with such a car, they loose billions in the oil industry. So they have no incentive to do that. New options do appear on the market like the new toyota prius with solar panel, but if you look at it you will see that they didn't even try to maximize the solar panel size. Still it gets 2 km extra range in bad conditions. Triple that and you have 6 km, in real conditions. If you use your car every other day, you will never charge it, ever. If you get average or above sun, you can drive it daily and not charge it ever. A big problem if you sell oil. The problem with green energy is that it is very democratic and hard to control. Nobody with big money is interested in that. To understand who controls your life, see all the draconian measures taken against electric scooters: cheap, not poluting, democratic, don't need a lot of space and so on. Everyone with money said: we can't allow that. Write defamatory articles in the media they control, pass laws against it and so on.

SideburnsOfDoom 6mo ago
> The problem with green energy is that it is very democratic and hard to control. It's not that I totally disagree with this - there is some truth to it. But it has no bearing at all on the question "can I put the panels on the car instead?" Which has been debunked in this thread and elsewhere many, many times. The counterargument to what you say is that Solar is in fact booming. It is coming - oil money can slow it, but not stop it. They have more success in some countries than others. It's not a coincidence that China, which course desires energy independence but doesn't have access to a lot of oil, is leading the way. Sorry USA, you're laggards now. But solar + battery is on an exponential ramp-up and getting big now. Each shock like the current Hormoz idiocy makes the case for it even more to the rest of the world. It's coming, fast. Just, it's not useful on car roofs. That's a poor choice of panel location.
- bryanlarsen 6mo ago
  > China doesn't have access to a lot of oil Just an aside, but China is the 5th largest oil producer. They have a lot of oil. The problem is that they're the 2nd largest oil consumer, so are still importing. Their current course is sufficient to achieve energy independence. It's kind of unfortunate they don't need to further decarbonize to achieve that independence. There are some other fields that aren't yet economically valid to decarbonize. If China had a non-economic reason to decarbonize jet fuel, steel, plastic etc they might drive enough volume to make them economic.

shepherdjerred 6mo ago

Hyundai had this https://techcrunch.com/2022/03/23/hyundai-sonata-hybrid-roof/ https://techcrunch.com/2022/03/23/hyundai-sonata-hybrid-roof... > After baking in the sun all day, the car can add 3-4 miles to its range.