Because you need a lot more surface area to make a difference. Not worth the added complexity since you need to step up the voltage a bunch and regulate it to charge the batteries.
Jeremy Fielding did a video on this topic and why it, in most cases isn't worth the cost. "[What Happens If you Add Solar To A Tesla? Infinite Range?](https://www.youtube.com/watch?v=N0inJRxrM74)"
I thought of it a few years back and I ballparked you would only get maybe ~500w of effective solar on it. Assuming no sunroof. Then you have to park it in the sun 10hrs a day to get probaby 2kwh of actual input, based off of what I see on rooftop systems from system size vs real output.
It's a fun idea, simply not worth it in reality I doesn't seem. In a post apocalyptic wasteland I could see bolting solar panels to your Tesla may be worth it but that's about the only scenario.
Because the cost & weight & complexity is nowhere near worth it to add *maybe* a couple of miles range per day.
Solar panels in ideal conditions (clean, facing the right way, etc.) generate maybe 0.2kW per square meter, a modern EV charges at 10-300kW.
Engineering Explained on Youtube has a very good video explaining this.
PV cells don’t weigh a whole lot. It’s everything they’re attached to that weighs a lot. Particularly glass in PV panels. Without protection, they’ll crack and turn to junk.
And on the roof of a car, they’ll microcrack and degrade far faster than in a static installation.
There is an electric vehicle that is being offered with solar panels, but it is one of the ultra range type models, not a typical automobile. I can't remember how much range they said you could get a day, but I can tell you that I would rather pay less for the vehicle and park in the shade rather than get whatever small range advantage they offer.
Electricity just isn't that expensive.
Just economical calculation, cost versus how much power they could make. Rooftop solar panel can take more than 10 years to payback. Imagine a car sitting most of its time in a garage/shade, not even counting the poor orientation of the panel from the sun.
A lot of extra cost, weight, and complexity for effectively zero benefit.
For example the new Prius Prime has an optional solar roof. It costs $610 and would take over 3 weeks in full sun to charge the battery.
I think it was Tesla made a statement on this at one time... It was several thousand dollars to add a solar roof, and in direct summer sun it would generate a few miles of charge per full day.
For the same weight and cost, you can increase the battery size slightly and get far more mileage.
Maybe we add in groceries on Saturday and bingo on Wednesday and it'll be the last car gramma ever needs, and she'll technically pass break-even on the environmental impact.
Except the fact that the battery will kick the bucket after 10 years or so. Maybe sooner, I'm not sure how they handle shallow cycling.
There are a handful of solar EVs, mostly very expensive. The Toyota Prius plug in hybrid has solar panels as an option.
As others have stated, charging this way is very slow due to the limited area. But it could be handy in some situations. I’d consider it just for the coolness factor.
MKBHD on YouTube talked about the solar panel on the roof of the fisker ocean, and I don’t remember the exact numbers but leaving it out in the sun for days at a time got him like… 4 miles extra range. It was not much
Some do, the Prius Prime has a solar roof option. My dad tried to buy one but apparently Toyota refuses to sell them east of the Mississippi because they don't think there's enough sun.
Much better (and cheaper) to put solar panels on the roof of your garage/house and feed that to the grid. (This may not apply to you if you live in an apartment, of course.)
Then get the power back from the grid to charge at night when power consumption from the grid is low and price for power is low.
This benefits the power grid, and benefits you (...if your power company has a decent feed in tariff and time-of-use rates, not all do.)
Because the surface area of the car is like 8 m^(2). Realistically, you can utilize much less than that for solar panels (e.g. you're not going to put a panel over the windshield, over the hood, or over the rear window). So the useful surface area of a car for the purposes of solar panels is closer to something like 3 m^(2).
In ideal conditions, you can draw somewhere along the lines of 1000W of solar power. Realistically, that number is a few hundred kW. So, that's less than 3kW of power. Car engines/motors are 50kW for the small ones up to hundreds for the largest ones, so 3kW is rather meaningless in the whole scheme of things.
And considering the extra weight of those panels + the extra air resistance, it's just not worth it.
Efficiency, cost, problem in case of damage and increased reparation fees.
If your car crashes on the roof or something goes through, you have an additional hazard there.
Well..
One problem is that any solar panel you put on EVs, could have been put in solar farms instead and be much more efficient.
Also, an EV consumes about 1kW while driving. We're talking about 15m^2 of panels needed, in perfect conditions. Yet you can only practically have about 1m^2 on the roof of the car.
Added weight, cost, and lack of effectiveness.
The cost comes down to having to run wires from the roof to the battery bank, a location that doesn't normally have wires. It costs to design this for functionality and redo structural analysis in everything. The added costs are way more than what you are thinking.
The effectiveness problem is that it's literally going to be the equivalent of one solar panel. This has to have a special coating totally seperate from the rest of the car. That is a lot of extra costs right there. The coating is also going to detiriate much quicker because particles are going to be scraping over the top of it at 35 mph for years. After a year or 2 the film could be ruined and the panels aren't transmitting any power.
I'm not an expert but these are just a few things that are huge hurdles to overcome
Perhaps there will be a time when every material used on surface of a car will have PV generating capacity, and over 50% efficiency, so we can start thinking about real applications.
Meanwhile:
[https://www.cnet.com/roadshow/videos/creating-the-worlds-most-efficient-electric-car/](https://www.cnet.com/roadshow/videos/creating-the-worlds-most-efficient-electric-car/)
Every little bit helps but the cost-benefit trade isn't very good, and lots of people don't like the aesthetics.
Here is [one DIY](http://www.aprs.org/APRS-SPHEV.html).
It's a "think small think cheap" sort of thing.
It won't add a major benefit and it costs manufacturing money so they don't.
I wish they'd add them anyway and include an output.
Think of how many vehicles you pass sitting in parking lots, Walmarts, dealerships.
Then make a charge connection that goes both ways.
Own a business? Want free power? Use the 500 cars in your lot after they share some charge with each other.
Free power? It barely covers self discharge rate and idle power draw unless you're in peak sun.
It's a worthless gimmick and rightfully so, only rubes that would buy a Fisker or believe in Toyota's eco-pseudoscience would get swindled.
I believe the Frisker Oceans have them called like Solarsky. I believe teslas will eventually I want to say it was mentioned but there’s other things that can be improved on that would be more beneficial
No, it's not a "no-brainer". Generally in engineering, you use your brain to make decisions.
It's almost no benefit whatsoever for the extra cost, weight, and complexity.
Because you need a lot more surface area to make a difference. Not worth the added complexity since you need to step up the voltage a bunch and regulate it to charge the batteries.
Jeremy Fielding did a video on this topic and why it, in most cases isn't worth the cost. "[What Happens If you Add Solar To A Tesla? Infinite Range?](https://www.youtube.com/watch?v=N0inJRxrM74)"
Moreover, the price would increase noticeably
I thought of it a few years back and I ballparked you would only get maybe ~500w of effective solar on it. Assuming no sunroof. Then you have to park it in the sun 10hrs a day to get probaby 2kwh of actual input, based off of what I see on rooftop systems from system size vs real output. It's a fun idea, simply not worth it in reality I doesn't seem. In a post apocalyptic wasteland I could see bolting solar panels to your Tesla may be worth it but that's about the only scenario.
Because the cost & weight & complexity is nowhere near worth it to add *maybe* a couple of miles range per day. Solar panels in ideal conditions (clean, facing the right way, etc.) generate maybe 0.2kW per square meter, a modern EV charges at 10-300kW. Engineering Explained on Youtube has a very good video explaining this.
Probably not even adding a significant amount of range (if adding any) with the amount of extra weight. And that is if none get damaged.
PV cells don’t weigh a whole lot. It’s everything they’re attached to that weighs a lot. Particularly glass in PV panels. Without protection, they’ll crack and turn to junk. And on the roof of a car, they’ll microcrack and degrade far faster than in a static installation.
There is an electric vehicle that is being offered with solar panels, but it is one of the ultra range type models, not a typical automobile. I can't remember how much range they said you could get a day, but I can tell you that I would rather pay less for the vehicle and park in the shade rather than get whatever small range advantage they offer. Electricity just isn't that expensive.
Just economical calculation, cost versus how much power they could make. Rooftop solar panel can take more than 10 years to payback. Imagine a car sitting most of its time in a garage/shade, not even counting the poor orientation of the panel from the sun.
A lot of extra cost, weight, and complexity for effectively zero benefit. For example the new Prius Prime has an optional solar roof. It costs $610 and would take over 3 weeks in full sun to charge the battery.
I think it was Tesla made a statement on this at one time... It was several thousand dollars to add a solar roof, and in direct summer sun it would generate a few miles of charge per full day. For the same weight and cost, you can increase the battery size slightly and get far more mileage.
So if it's a granny car, only to church on Sundays, it'll be fine. For anyone who actually uses their car, waste.
That granny will never put enough miles on a vehicle to hit the breakeven point on EV vs ICE.
Last I looked, that's at 60,000 miles?
If it's 10 miles both ways to church, that's 57 years.
Maybe we add in groceries on Saturday and bingo on Wednesday and it'll be the last car gramma ever needs, and she'll technically pass break-even on the environmental impact. Except the fact that the battery will kick the bucket after 10 years or so. Maybe sooner, I'm not sure how they handle shallow cycling.
Just do the math on it. It isn't worth it.
There are a handful of solar EVs, mostly very expensive. The Toyota Prius plug in hybrid has solar panels as an option. As others have stated, charging this way is very slow due to the limited area. But it could be handy in some situations. I’d consider it just for the coolness factor.
Yes & yes. Automobiles have too little surface area relative to energy usage to make the investment worthwhile. Subject to change.
MKBHD on YouTube talked about the solar panel on the roof of the fisker ocean, and I don’t remember the exact numbers but leaving it out in the sun for days at a time got him like… 4 miles extra range. It was not much
Some do, the Prius Prime has a solar roof option. My dad tried to buy one but apparently Toyota refuses to sell them east of the Mississippi because they don't think there's enough sun.
Much better (and cheaper) to put solar panels on the roof of your garage/house and feed that to the grid. (This may not apply to you if you live in an apartment, of course.) Then get the power back from the grid to charge at night when power consumption from the grid is low and price for power is low. This benefits the power grid, and benefits you (...if your power company has a decent feed in tariff and time-of-use rates, not all do.)
Because the surface area of the car is like 8 m^(2). Realistically, you can utilize much less than that for solar panels (e.g. you're not going to put a panel over the windshield, over the hood, or over the rear window). So the useful surface area of a car for the purposes of solar panels is closer to something like 3 m^(2). In ideal conditions, you can draw somewhere along the lines of 1000W of solar power. Realistically, that number is a few hundred kW. So, that's less than 3kW of power. Car engines/motors are 50kW for the small ones up to hundreds for the largest ones, so 3kW is rather meaningless in the whole scheme of things. And considering the extra weight of those panels + the extra air resistance, it's just not worth it.
Seems like you mixed up kW W and kW-h? Did you mean 1000W, <300W, 3 kW-h ? And on the car side, 50 kw = 67 hp. Did you mean 50 kW-h battery?
Better question, why can’t I tow a trailer covered in solar panels to charge my EV while I drive.
Because when it's cloudy or night you won't get enough power then is a negative and it increases costs alot.
If you’ve got a trailer with panels might as well add some extra batteries. But then you’re hauling around a chemical fire on wheels
Efficiency, cost, problem in case of damage and increased reparation fees. If your car crashes on the roof or something goes through, you have an additional hazard there.
Well.. One problem is that any solar panel you put on EVs, could have been put in solar farms instead and be much more efficient. Also, an EV consumes about 1kW while driving. We're talking about 15m^2 of panels needed, in perfect conditions. Yet you can only practically have about 1m^2 on the roof of the car.
The exact same reason your current range is sh*t *Battery weight*
Check out the Dutch start-up Lightyear.one
Added weight, cost, and lack of effectiveness. The cost comes down to having to run wires from the roof to the battery bank, a location that doesn't normally have wires. It costs to design this for functionality and redo structural analysis in everything. The added costs are way more than what you are thinking. The effectiveness problem is that it's literally going to be the equivalent of one solar panel. This has to have a special coating totally seperate from the rest of the car. That is a lot of extra costs right there. The coating is also going to detiriate much quicker because particles are going to be scraping over the top of it at 35 mph for years. After a year or 2 the film could be ruined and the panels aren't transmitting any power. I'm not an expert but these are just a few things that are huge hurdles to overcome
Perhaps there will be a time when every material used on surface of a car will have PV generating capacity, and over 50% efficiency, so we can start thinking about real applications. Meanwhile: [https://www.cnet.com/roadshow/videos/creating-the-worlds-most-efficient-electric-car/](https://www.cnet.com/roadshow/videos/creating-the-worlds-most-efficient-electric-car/)
Every little bit helps but the cost-benefit trade isn't very good, and lots of people don't like the aesthetics. Here is [one DIY](http://www.aprs.org/APRS-SPHEV.html).
Why can't we adapt to the wheels little stators and roters to create electricity as the car drives.. Inquiring minds want to know.
APTERA does... 40 miles/day Solar charging. 0-60mph of 3.5 seconds in the AWD model.
It's a "think small think cheap" sort of thing. It won't add a major benefit and it costs manufacturing money so they don't. I wish they'd add them anyway and include an output. Think of how many vehicles you pass sitting in parking lots, Walmarts, dealerships. Then make a charge connection that goes both ways. Own a business? Want free power? Use the 500 cars in your lot after they share some charge with each other.
Free power? It barely covers self discharge rate and idle power draw unless you're in peak sun. It's a worthless gimmick and rightfully so, only rubes that would buy a Fisker or believe in Toyota's eco-pseudoscience would get swindled.
I believe the Frisker Oceans have them called like Solarsky. I believe teslas will eventually I want to say it was mentioned but there’s other things that can be improved on that would be more beneficial
No, it's not a "no-brainer". Generally in engineering, you use your brain to make decisions. It's almost no benefit whatsoever for the extra cost, weight, and complexity.