# Solar Roofs on EVs



## User.45

Been looking at Ioniq 5 videos and turns out the Norwegian version (or French?!) version has a Solar roof that is thought to generate up to 1300 miles per year. That covers most of our innercity needs. 









						Hyundai's new electric car has a solar panel roof and can charge other EVs
					

Meet the new Hyundai Ioniq 5




					www.techradar.com


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## Hrafn

P_X said:


> Been looking at Ioniq 5 videos and turns out the Norwegian version (or French?!) version has a Solar roof that is thought to generate up to 1300 miles per year. That covers most of our innercity needs.
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> Hyundai's new electric car has a solar panel roof and can charge other EVs
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> Meet the new Hyundai Ioniq 5
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> www.techradar.com



I've wondered about a lot of this type applications.  I still drive all ICEs, despite interest in hybrids and EVs.


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## AG_PhamD

For the cost of what such an option will add to the car is it probably worth it? Probably not? From an environmental standpoint, assuming at least some of your energy comes from renewables, it’s probably not worth it either. For some people though it might be worth it. This is assuming the cost of the option is priced far higher than the actual value of similar solar panels. 

I know some sailboat manufacturers are working on flexible solar panels built into shaped structures of the boat, such as the mast and coachroof to maximize surface area. Or maybe flexible panels to unfurl over the windshield and/or rear window, or in the case of pickups, tonneau covers. If you could double the 1300mi/yr figure, you’re getting close to half the average American’s commute distance.


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## Ulenspiegel

The ultimate solution would be a mobile utility trailer with extra batteries.


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## User.45

Hrafn said:


> I've wondered about a lot of this type applications.  I still drive all ICEs, despite interest in hybrids and EVs.



There are concept cars for the concept. This looks like a glorified bike, but probably scratches the max you can get. They claim that at climates like the continental USA, you could get a 20mi a day range without ever charging.









						Vehicle | Aptera
					

Vehicle |




					aptera.us


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## User.45

A Fugly contender from Germany with only a 190 mile range and probably painfully slow, but with 70mi per day solar charging. If I never had to think about charging/refueling, I'd happily take it for 30,000 Euros. 
















						The Sion - the car that charges itself | Sono Motors
					

The Sion is the first series-ready solar electric vehicle that is able to charge the battery via the power of the sun. All this for just €29,900



					sonomotors.com


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## User.45

Ulenspiegel said:


> The ultimate solution would be a mobile utility trailer with extra batteries.
> 
> View attachment 11559








			https://sonomotors.com/site/assets/files/6479/sono-motors-trucks-and-trailer-solar-fact-sheets-en.pdf
		


@Ulenspiegel, they have your solution done already Covers refrigeration or extends range.


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## User.45

AG_PhamD said:


> For the cost of what such an option will add to the car is it probably worth it? Probably not? From an environmental standpoint, assuming at least some of your energy comes from renewables, it’s probably not worth it either. For some people though it might be worth it. This is assuming the cost of the option is priced far higher than the actual value of similar solar panels.
> 
> I know some sailboat manufacturers are working on flexible solar panels built into shaped structures of the boat, such as the mast and coachroof to maximize surface area. Or maybe flexible panels to unfurl over the windshield and/or rear window, or in the case of pickups, tonneau covers. If you could double the 1300mi/yr figure, you’re getting close to half the average American’s commute distance.








For the IO5 it would cost 1500 Euros. Bear in mind that most of Northern Europe has light exposure most comparable to Alaska, whereas Continental US has at least as much exposure as Southern Europe. Based on the above estimates, it would take 3-4 hours to charge 1 mile of range. Not too impressive, but It could easily extend my summer charging needs to nearly zero.


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## Zoidberg

It's a bad idea (in most cases).


Cost of roof solar panels vs effectiveness (terrible ROI)
Very limited surface area, which makes the improvement negligible in most cases.
Poor orientation and position (unless you're lucky and you can park in such a way that it's facing the sun directly).
A quick calculation for that Hyundai brings up the following numbers:
For the average price in the US (10.42c/kWh according to google), that $1500 will save you a little over $22 dollars a year. The cost of the roof will then be justified after about 70 years.
Because it will never be the main ways to charge, you'll still need to connect the car to a proper charger so that free mile charged every three hours can be obtained in a matter of seconds from a regular charger.

In addition, for those designs that include panels all around the car, it becomes an absolutely terrible idea, because you also get the following disadvantages:

At most 50% will be used at any one time (unless you happen to live in a system with two stars like Tatooine and they line up just right).
Terrible orientation (this can -I assume- be somewhat mitigated with microlenses, but the price/effectiveness would have to be determined).
Any small bump on the car will break the PV panels and make the repair very costly.
For the cost of on-board solar panels, you can have some proper solar panels that will generate WAY more power than the on-board panels, or more batteries in the car, or pay *a lot* of miles of charge when away (eg more than 80 full charges in a Tesla). All these options make much more sense.

It's the kind of thing I see as just a way to swindle money from investors who don't know any better, or the kind of desperate selling point auto manufacturers are trying to push to the equally non-educated public to try to differentiate their offering from better competition. The only real life application I see is in some long range overlanding 4WD for camping where solar panels are the norm and every electron counts.

I'd go as far as saying that any car manufacturer that has gone as far as including that feature in their cars should be disregarded because clearly they don't have the good engineering sense to stop and reconsider bad ideas. (Again, this doesn't apply to 4wd cars).


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## User.168

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## User.168

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## DT

Solar on larger electric boats makes some sense, [potentially] larger surface area, more fixed orientation, [longer] periods of no battery use.


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## Zoidberg

theSeb said:


> But it would be the ultimate post apocalypse vehicle.



I haven't put too much thought into that eventuality, but I'm going to go on a limb and say that in case of a real apocalypse, you do not want an electric car.


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## DT

Zoidberg said:


> I haven't put too much thought into that eventuality, but I'm going to go on a limb and say that in case of a real apocalypse, you do not want an electric car.




I feel like this may be the best post-apocalypse option ...


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## User.45

Zoidberg said:


> It's a bad idea (in most cases).
> 
> 
> Cost of roof solar panels vs effectiveness (terrible ROI)
> Very limited surface area, which makes the improvement negligible in most cases.
> Poor orientation and position (unless you're lucky and you can park in such a way that it's facing the sun directly).
> A quick calculation for that Hyundai brings up the following numbers:
> For the average price in the US (10.42c/kWh according to google), that $1500 will save you a little over $22 dollars a year. The cost of the roof will then be justified after about 70 years.
> Because it will never be the main ways to charge, you'll still need to connect the car to a proper charger so that free mile charged every three hours can be obtained in a matter of seconds from a regular charger.
> 
> In addition, for those designs that include panels all around the car, it becomes an absolutely terrible idea, because you also get the following disadvantages:
> 
> At most 50% will be used at any one time (unless you happen to live in a system with two stars like Tatooine and they line up just right).
> Terrible orientation (this can -I assume- be somewhat mitigated with microlenses, but the price/effectiveness would have to be determined).
> Any small bump on the car will break the PV panels and make the repair very costly.
> For the cost of on-board solar panels, you can have some proper solar panels that will generate WAY more power than the on-board panels, or more batteries in the car, or pay *a lot* of miles of charge when away (eg more than 80 full charges in a Tesla). All these options make much more sense.
> 
> It's the kind of thing I see as just a way to swindle money from investors who don't know any better, or the kind of desperate selling point auto manufacturers are trying to push to the equally non-educated public. The only real life application I see is in some long range overlanding 4WD for camping where solar panels are the norm and every electron counts.
> 
> I'd go as far as saying that any car manufacturer that has gone as far as including that feature in their cars should be disregarded because clearly they don't have the good engineering sense to stop and reconsider bad ideas. (Again, this doesn't apply to 4wd cars).



I don’t disagree with most you’ve written there, but If you approach this from an investment perspective, Electric cars are never good investments. A solar roof that can produce 3 to 5 miles a day is not a cost saving feature, it’s a convenience feature that can eliminate  the need to charge at all for some, like me. If you park in a garage, it’s 100% pointless. If you street park and can’t plug in daily it saves a ton of hassle.


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## DT

"Pedal faster, the flesh eating mutants are catching up!"


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## Zoidberg

P_X said:


> I don’t disagree with most you’ve written there, but If you approach this from an investment perspective, Electric cars are never good investments. A solar roof that can produce 3 to 5 miles a day is not a cost saving feature, it’s a convenience feature that can eliminate  the need to charge at all for some, like me. If you park in a garage, it’s 100% pointless. If you street park and can’t plug in daily it saves a ton of hassle.



Solar panels are extremely dependent on orientation. Unless you can park your car on an ideal slope for your latitude, you won't see the advertised outputs. In reality, you'll lose between 1 and 5 miles of range per day from normal battery drain (aka "vampire drain"), just from having your car sitting idle (assuming the temperature is just right, if it's too cold the apparent loss will be much worse). So at best, the integrated roof keeps it at the same level, and you'll still have to recharge it, thus rendering the roof PV useless (a quick 5 miles top up is done in mere minutes).

That money is -much- better spent elsewhere.

EVs can be good investments (as far as a car can be considered an investment, that is). In London, for instance, the daily charge for old-ish cars is £15, and while most recent ICE cars are exempt, it's just a matter of time before they apply it to all non-EV cars. Even if we just consider the cost of gas, at £70 for a tank, it adds up quickly if you're going to drive a lot. (I know in the US the economics are different)


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## User.45

Zoidberg said:


> Solar panels are extremely dependent on orientation. Unless you can park your car on an ideal slope for your latitude, you won't see the advertised outputs. In reality, you'll lose between 1 and 5 miles of range per day from normal battery drain (aka "vampire drain"), just from having your car sitting idle (assuming the temperature is just right, if it's too cold the apparent loss will be much worse). So at best, the integrated roof keeps it at the same level, and you'll still have to recharge it, thus rendering the roof PV useless (a quick 5 miles top up is done in mere minutes).
> 
> That money is -much- better spent elsewhere.



People spend similar money on software upgrades to speed up their Teslas, so where money best spent is a relative thing. I’ll add, that I definitely don’t get that much vampire drain. Left my I3 in a parking lot for 5 weeks this summer. I lost only a few miles, so this really depends on the car.


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## Zoidberg

P_X said:


> People spend similar money on software upgrades to speed up their Teslas, so where money best spent is a relative thing. I’ll add, that I definitely don’t get that much vampire drain. Left my I3 in a parking lot for 5 weeks this summer. I lost only a few miles, so this really depends on the car.



There's different ways to measure drain: by measuring the actual voltage and by doing a sort of "dead reckoning", and measuring how much is used and subtracting it from the last known top-up. Both can be slightly inaccurate, and probably won't show a small loss over small periods of time. In other words, I wouldn't count on the car (any car, whether it's a Tesla or a BMW) to accurately display small losses of under 5 miles. Indeed, the only way to actually measure the effect of on-board PV panels would be go in there with tester and measure their actual output.

Back to the roof thing: it would be nice, but it's pointless (in almost all cases). That said, people indeed spend more than that to upgrade the colour of the paint, and they often drive with suboptimal tyres and tyre pressures, which have a much larger impact on the range, and at suboptimal speeds so I guess there are worse ideas. My issue with them is that they are sold as the self-charging car, which is a lie. Even specialised solar cars that look like this and weigh like a motorcycle are dependent on external charging at night:
	

	
	
		
		

		
		
	


	




Only top of the range concept cars claim charging rates that could be considered self-charging for daily use, and as of today, they are still concept cars. The Lightyear might do it, but it's going to cost at least 150K and even then will only charge what can be obtained in 20 minutes, so there's really not much point to it.


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## User.45

Zoidberg said:


> There's different ways to measure drain: by measuring the actual voltage and by doing a sort of "dead reckoning", and measuring how much is used and subtracting it from the last known top-up. Both can be slightly inaccurate, and probably won't show a small loss over small periods of time. In other words, I wouldn't count on the car (any car, whether it's a Tesla or a BMW) to accurately display small losses of under 5 miles. Indeed, the only way to actually measure the effect of on-board PV panels would be go in there with tester and measure their actual output.



You brought up the hypothesis of losing miles quicker than charging. I can tell you that if your minimum estimate of vampire drain was correct, over 35 days, my battery would have been drained completely. Since that drain is likely proportionate to the capacity of the system, but using solar panels isn't necessarily, it could have a greater impact on the car's usability that has a shorter range.



Zoidberg said:


> Back to the roof thing: it would be nice, but it's pointless (in almost all cases). That said, people indeed spend more than that to upgrade the colour of the paint, and they often drive with suboptimal tyres and tyre pressures, which have a much larger impact on the range, and at suboptimal speeds so I guess there are worse ideas. My issue with them is that they are sold as the self-charging car, which is a lie. Even specialised solar cars that look like this and weigh like a motorcycle are dependent on external charging at night:
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> Only top of the range concept cars give charging rates that could be considered self-charging for daily use, and as of today, they are still concept cars.



You're making the assumption that daily use means the same thing across the board. I defined mine already and clearly differs from yours.


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## DT

P_X said:


> I’ll add, that I definitely don’t get that much vampire drain.




I leave garlic in mine, it really reduces it ...


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## User.45

Ioniq 5 appears to have the same solar roof as the Sonata, which can roughly generate between 0.6 and 2 KWh per day. So that's 2-6 miles a day with an Ioniq 5. 







DT said:


> I leave garlic in mine, it really reduces it ...



That may also explain the hanging crosses in some of these cars


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## User.45

LightYear One promises up to 45mi charge using 5m2 of solar panel surface. 
For $160,000 it's definitely not cost efficient, but an interesting concept. 





__





						Long Range Solar Electric Vehicle — Lightyear 0
					

Discover Lightyear 0. Charge less and drive 725 km with energy-efficient technology (only 83 wh/km). Find interior and exterior photos and learn about the specifications and details of Lightyear 0.



					lightyear.one


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## SuperMatt

P_X said:


> LightYear One promises up to 45mi charge using 5m2 of solar panel surface.
> For $160,000 it's definitely not cost efficient, but an interesting concept.
> 
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> __
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> Long Range Solar Electric Vehicle — Lightyear 0
> 
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> Discover Lightyear 0. Charge less and drive 725 km with energy-efficient technology (only 83 wh/km). Find interior and exterior photos and learn about the specifications and details of Lightyear 0.
> 
> 
> 
> lightyear.one



If I move to Arizona…


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## User.45

SuperMatt said:


> If I move to Arizona…



They are planning a 40K version, LOL. I don't believe any of these "cheap versions". But since the car is reported to do 100mi using 5 kWh, (it's about 25 for efficient TM3s in real world and 30 for Ioniq in WLTP). So it isn't really the solar panels that do the heavy lifting. This range extension estimate would translate to about 16 mi to the Ioniq 5 (3m2 vs 5m2 panels and 50% of efficiency).


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## User.168

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## User.45

theSeb said:


> If my car could generate around 16 miles per day by itself via whatever means, then I would hardly ever need to plug it in to charge.



On one of the Ioniq5 forums, someone stated his car generated 2-2.5 miles a day in the Finland in November. That system could generate close to 10 miles where I live in the summer.


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