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Yes. This pops up on EV forums/reddit regularly "hey why don't we just put the solar panels on the car". It's a bearish indicator when any EV startup pumps a n

Yes. This pops up on EV forums/reddit regularly "hey why don't we just put the solar panels on the car". It's a bearish indicator when any EV startup pumps a new prototype where this is a key feature. Short version: adds weight and maybe $2000 manufacturing cost to the car. Best case current tech it maybe adds $50/year of electricity to your car, requiring you to park outdoors, in good FULL sun, in parts of the world that get a lot of sun-hours-per-year. Further solar roof of a car is not at the idea angle that a home roof is. Remember while you are parking your car in said parking spots you are also baking the insides so in weather above say 55F, it will get quite hot and probably need to turn on the HVAC systems to cool the cabin and/or battery periodically.. wiping out some of your solar charging gains. Aesthetically, tt replaces the lovely glass roof many EVs have and so makes the experience worse. If you have a garage charger or charger at work, this is rounding error and irrelevant. If you don't and need to fast charge regularly, the fact that your car adds LESS THAN 1kWh/day from solar charging will save you.. 24 seconds of fast charging, per day of solar charging.. lol.

JKCalhoun 4y ago
A solar carport sounds ideal. Guessing many HOA's would lose their shit over that though.
- matthewdgreen 4y ago
  This is the one I want to build (though in a smaller size.) It’s attractive and uses panels directly as the roof. I am debating whether to get into a war with my HOA over it. https://timberhomesllc.com/our-work/outdoor-structures/vermont-solar-carport/ https://timberhomesllc.com/our-work/outdoor-structures/vermo...
  - chipsa 4y ago
    If your state has rules about HOAs not being able to block solar panels, it's probably worth it.
- Rebelgecko 4y ago
  Those are becoming somewhat common for big parking lots in Southern California, like at schools
threeseed 4y ago
Short version: * EVs are already ridiculous heavy. * $2000 is a blip in the price of a car and will be recouped. * You often don't have a choice whether to park in sun or shade. At least a solar roof gives you some benefits. * Large percentage of the world don't get to decide to have chargers at home/work.
- Teever 4y ago
  If the extra cost is $2000 and a solar equipped car will recoup at best $50/year as OP stated then $2000/$50/year is 40 years to best case time recoup the cost of the panels. Also you don't seem to be aware of this but $2000 is a lot of money to some people -- It's more than they spend on personal transportation.
- powera 4y ago
  Nope. * The attitude "$2000 is a blip" is why electric cars are expensive. * People without home electricity (or who live in dense urban areas without parking) are not the market for the car at this time. There is no reason to make everyone else suffer out of theoretical concern for people who don't even own cars now.
  - threeseed 4y ago
    * You will recoup the $2000 in reduced electricity costs. * People without home electricity are exactly the market for this car. * Who is suffering exactly by offering this as an option ?
    - steveBK123 4y ago
      $2000 of electricity would take these cars 40 years to generate. Their warranty will be up in 4 years, and they will be in the scrap yard by 15 years, at best.
    - causality0 4y ago
      Two grand in electricity from a couple square meters of panel will take an incredibly long time. Like an idiotically long time. This is a scam marketing ploy and nothing more.
moffkalast 4y ago
It would make more sense to sell an optional add-on that's just a foldable set of panels that fits perfectly in the boot or frunk, one that you can then extend to way beyond the car's surface area, align to the right angle and plug in. They even make those light flexible ones now. The main use case for this would be something like driving an EV across a desert or some backcountry well outside civilization I guess, otherwise it's probably easier to just find an electric socket somewhere.
- mikestew 4y ago
  It’s such an impractical option, starting with incredibly long charge times, that even for backcountry there would be better and more reliable options. For one, it won’t work in the woods because no sun. So the market consists of those crossing a remote desert. Those six people won’t even cover the cost of tooling. I mean, the math isn’t hard. 200W out of a panel (at best), multiple by 5 hours to get a kilowatt hour. How many of those do you need to get back to civilization? Our Leaf gets 4 miles per kWh. The hypothetical desert overland vehicle probably gets half that. You’re better off bring extra water and walking back for help if it comes to it.
  - moffkalast 4y ago
    Fair enough, might as well chop some wood and burn it in a generator lol.
    - rhino369 4y ago
      Don't give GM any ideas. The Tri-Volt coming soon.
      - moffkalast 4y ago
        Well they already made gas turbine engines back in the day, wouldn't be much of a stretch jumping to a steam turbine haha. There's also woodgas.
    - egberts1 4y ago
coredog64 4y ago
Toyota offered a solar roof option on the Prius for a short time. The intent was to provide power to run the AC for a car that wasn’t parked in the shade. I’ve worked at several offices where there was zero/limited covered parking and I would have grabbed this option for my Prius if it had been available.
- steveBK123 4y ago
  Toyota yanking the feature tells us something about the consumer uptake, cost-benefit, and ROI.
  - brookst 4y ago
    So what does Toyota re-introducing the feature this year[0] tell us? 0. https://www.roadandtrack.com/news/a41978716/2023-toyota-prius/ https://www.roadandtrack.com/news/a41978716/2023-toyota-priu...
    - danuker 4y ago
      Perhaps, the continuous price decrease of solar panels?
    - parker_mountain 4y ago
      It tells us that in the last 10 years or so, a component has had its price decrease and its efficiency increase. It also tells us that solar panels on a vehicle, even if they don't lead to huge benefit, make for great marketing.
- panick21_ 4y ago
  With a modern electric car you just use your phone to turn on the AC before you get there.
  - mcv 4y ago
    I don't waste the AC on something like that but just open all the doors for a minutes or so.
Retric 4y ago
You can get a lot more than 1kWh per day from solar charging. It’s really popular on motor homes and narrow boats etc because you can actually get significant amounts of power. Parking in full sun in an area with significant solar power isn’t something Everyone does, but for those who do a solar car could average 5kWh per day at 20+c/kWh for electricity and more for fast charging that’s ~1$/ day of electricity and 3600$ over 10 years. However EV’s can have significant discharge when parked, being able to trickle charge enough to offset this is worth vastly more than the value of the electricity you are supplying. A solar powered EV isn’t a great investment, but with cars lasting 25 years the economics can work out. Especially if the car can directly use solar power and thus reduce the number of charge/discharge cycles. PS: National average is currently 16c/kWh some states are much higher than this. Again people who have cheap electricity aren’t the target audience.
- SideQuark 4y ago
  >5kWh per day at 20c/kWh A standard perfectly installed 400W solar panel gets around 1.8 kWh a day [1]. Avg US electricity costs are 16c/kWh [2]. I think you vastly overstated the above. So some may get better, but ~half of people will get worse. So I'd guess this is actually under $0.30/day. >1$/ day of electricity and 3600$ over 10 years. ... i.e., if you park in perfect sun all day, every day, and there's no weather or seasonal changes, i.e., this is not possible. Picking a daily perfect value and assuming that value scales to all days is not a good estimate. Maybe, if someone is quite diligent and lucky, they will get 1/2 of the perfect value over time. So I'm at $0.30 per day at best, avg maybe $0.15 per day over 10 years, i.e., under $550 for 10 years. And of course now your solar panels are slightly degreaded, slightly less power generated, and, if you're lucky, you might get another 10 years out of them (they're on a car after all). So for a price of $2000, up front, for 20 years, you get $1k return. Of course, if you invested that $2K at 5% over 20 years you have $5300. So, not even close to being a good value. [1] https://www.solar.com/learn/how-much-energy-does-a-solar-panel-produce/ https://www.solar.com/learn/how-much-energy-does-a-solar-pan... [2] https://www.bls.gov/regions/midwest/data/averageenergyprices_selectedareas_table.htm https://www.bls.gov/regions/midwest/data/averageenergyprices...
  - 4y ago
thomastjeffery 4y ago
> Remember while you are parking your car in said parking spots you are also baking the insides so in weather above say 55F, it will get quite hot and probably need to turn on the HVAC systems to cool the cabin and/or battery periodically.. wiping out some of your solar charging gains. Only if you are choosing to park in the sun instead of parking in covered parking. That's almost never a choice your can actually make. The real utility of solar panels would be for driving in areas that don't have utilities (places to charge) near enough to charge from. Though, in that case, it still makes more sense to carry separate panels folded in storage than to integrate them into the roof.
- munchler 4y ago
  > it still makes more sense to carry separate panels folded in storage I wonder if the added weight of detachable panels would cancel out any benefit, though.
  - bluGill 4y ago
    Weight is an insignificant factor for cars. Wind resistance dominates the energy costs. Though the space used may change wind resistance.
- narag 4y ago
  Only if you are choosing to park in the sun instead of parking in covered parking. Biz idea: parking spot with panels as roof. You can recharge for some coins and keep the car cool.
dzhiurgis 4y ago
“California now requires all BEV’s to have solar roof and hood with at least 27% cell efficiency” and suddenly manufacturers marginal cost is $100.

JKCalhoun 4y ago

A solar carport sounds ideal. Guessing many HOA's would lose their shit over that though.

matthewdgreen 4y ago
This is the one I want to build (though in a smaller size.) It’s attractive and uses panels directly as the roof. I am debating whether to get into a war with my HOA over it. https://timberhomesllc.com/our-work/outdoor-structures/vermont-solar-carport/ https://timberhomesllc.com/our-work/outdoor-structures/vermo...
- chipsa 4y ago
  If your state has rules about HOAs not being able to block solar panels, it's probably worth it.
Rebelgecko 4y ago
Those are becoming somewhat common for big parking lots in Southern California, like at schools

threeseed 4y ago

Short version: * EVs are already ridiculous heavy. * $2000 is a blip in the price of a car and will be recouped. * You often don't have a choice whether to park in sun or shade. At least a solar roof gives you some benefits. * Large percentage of the world don't get to decide to have chargers at home/work.

Teever 4y ago
If the extra cost is $2000 and a solar equipped car will recoup at best $50/year as OP stated then $2000/$50/year is 40 years to best case time recoup the cost of the panels. Also you don't seem to be aware of this but $2000 is a lot of money to some people -- It's more than they spend on personal transportation.
powera 4y ago
Nope. * The attitude "$2000 is a blip" is why electric cars are expensive. * People without home electricity (or who live in dense urban areas without parking) are not the market for the car at this time. There is no reason to make everyone else suffer out of theoretical concern for people who don't even own cars now.
- threeseed 4y ago
  * You will recoup the $2000 in reduced electricity costs. * People without home electricity are exactly the market for this car. * Who is suffering exactly by offering this as an option ?
  - steveBK123 4y ago
    $2000 of electricity would take these cars 40 years to generate. Their warranty will be up in 4 years, and they will be in the scrap yard by 15 years, at best.
  - causality0 4y ago
    Two grand in electricity from a couple square meters of panel will take an incredibly long time. Like an idiotically long time. This is a scam marketing ploy and nothing more.

moffkalast 4y ago

It would make more sense to sell an optional add-on that's just a foldable set of panels that fits perfectly in the boot or frunk, one that you can then extend to way beyond the car's surface area, align to the right angle and plug in. They even make those light flexible ones now. The main use case for this would be something like driving an EV across a desert or some backcountry well outside civilization I guess, otherwise it's probably easier to just find an electric socket somewhere.

mikestew 4y ago
It’s such an impractical option, starting with incredibly long charge times, that even for backcountry there would be better and more reliable options. For one, it won’t work in the woods because no sun. So the market consists of those crossing a remote desert. Those six people won’t even cover the cost of tooling. I mean, the math isn’t hard. 200W out of a panel (at best), multiple by 5 hours to get a kilowatt hour. How many of those do you need to get back to civilization? Our Leaf gets 4 miles per kWh. The hypothetical desert overland vehicle probably gets half that. You’re better off bring extra water and walking back for help if it comes to it.
- moffkalast 4y ago
  Fair enough, might as well chop some wood and burn it in a generator lol.
  - rhino369 4y ago
    Don't give GM any ideas. The Tri-Volt coming soon.
    - moffkalast 4y ago
      Well they already made gas turbine engines back in the day, wouldn't be much of a stretch jumping to a steam turbine haha. There's also woodgas.
  - egberts1 4y ago

coredog64 4y ago

Toyota offered a solar roof option on the Prius for a short time. The intent was to provide power to run the AC for a car that wasn’t parked in the shade. I’ve worked at several offices where there was zero/limited covered parking and I would have grabbed this option for my Prius if it had been available.

steveBK123 4y ago
Toyota yanking the feature tells us something about the consumer uptake, cost-benefit, and ROI.
- brookst 4y ago
  So what does Toyota re-introducing the feature this year[0] tell us? 0. https://www.roadandtrack.com/news/a41978716/2023-toyota-prius/ https://www.roadandtrack.com/news/a41978716/2023-toyota-priu...
  - danuker 4y ago
    Perhaps, the continuous price decrease of solar panels?
  - parker_mountain 4y ago
    It tells us that in the last 10 years or so, a component has had its price decrease and its efficiency increase. It also tells us that solar panels on a vehicle, even if they don't lead to huge benefit, make for great marketing.
panick21_ 4y ago
With a modern electric car you just use your phone to turn on the AC before you get there.
- mcv 4y ago
  I don't waste the AC on something like that but just open all the doors for a minutes or so.

Retric 4y ago

You can get a lot more than 1kWh per day from solar charging. It’s really popular on motor homes and narrow boats etc because you can actually get significant amounts of power. Parking in full sun in an area with significant solar power isn’t something Everyone does, but for those who do a solar car could average 5kWh per day at 20+c/kWh for electricity and more for fast charging that’s ~1$/ day of electricity and 3600$ over 10 years. However EV’s can have significant discharge when parked, being able to trickle charge enough to offset this is worth vastly more than the value of the electricity you are supplying. A solar powered EV isn’t a great investment, but with cars lasting 25 years the economics can work out. Especially if the car can directly use solar power and thus reduce the number of charge/discharge cycles. PS: National average is currently 16c/kWh some states are much higher than this. Again people who have cheap electricity aren’t the target audience.

SideQuark 4y ago
>5kWh per day at 20c/kWh A standard perfectly installed 400W solar panel gets around 1.8 kWh a day [1]. Avg US electricity costs are 16c/kWh [2]. I think you vastly overstated the above. So some may get better, but ~half of people will get worse. So I'd guess this is actually under $0.30/day. >1$/ day of electricity and 3600$ over 10 years. ... i.e., if you park in perfect sun all day, every day, and there's no weather or seasonal changes, i.e., this is not possible. Picking a daily perfect value and assuming that value scales to all days is not a good estimate. Maybe, if someone is quite diligent and lucky, they will get 1/2 of the perfect value over time. So I'm at $0.30 per day at best, avg maybe $0.15 per day over 10 years, i.e., under $550 for 10 years. And of course now your solar panels are slightly degreaded, slightly less power generated, and, if you're lucky, you might get another 10 years out of them (they're on a car after all). So for a price of $2000, up front, for 20 years, you get $1k return. Of course, if you invested that $2K at 5% over 20 years you have $5300. So, not even close to being a good value. [1] https://www.solar.com/learn/how-much-energy-does-a-solar-panel-produce/ https://www.solar.com/learn/how-much-energy-does-a-solar-pan... [2] https://www.bls.gov/regions/midwest/data/averageenergyprices_selectedareas_table.htm https://www.bls.gov/regions/midwest/data/averageenergyprices...
- 4y ago

thomastjeffery 4y ago

> Remember while you are parking your car in said parking spots you are also baking the insides so in weather above say 55F, it will get quite hot and probably need to turn on the HVAC systems to cool the cabin and/or battery periodically.. wiping out some of your solar charging gains. Only if you are choosing to park in the sun instead of parking in covered parking. That's almost never a choice your can actually make. The real utility of solar panels would be for driving in areas that don't have utilities (places to charge) near enough to charge from. Though, in that case, it still makes more sense to carry separate panels folded in storage than to integrate them into the roof.

munchler 4y ago
> it still makes more sense to carry separate panels folded in storage I wonder if the added weight of detachable panels would cancel out any benefit, though.
- bluGill 4y ago
  Weight is an insignificant factor for cars. Wind resistance dominates the energy costs. Though the space used may change wind resistance.
narag 4y ago
Only if you are choosing to park in the sun instead of parking in covered parking. Biz idea: parking spot with panels as roof. You can recharge for some coins and keep the car cool.

dzhiurgis 4y ago

“California now requires all BEV’s to have solar roof and hood with at least 27% cell efficiency” and suddenly manufacturers marginal cost is $100.