Honestly it seems like a no-brainer to me to put a solar panel on the roof of electric cars to increase their action radius, so I figured there’s probably one or more good reasons why they don’t.
Also, I acknowledge that a quick google could answer the question, but with the current state of google I don’t want to read AI bullshit. I want an actual answer, and I bet there will be some engineers eager to explain the issues.
A few of them have. The core issue is it doesn’t add much range, while at the same time adding more cost, weight, and complexity. On a sunny summer day you can expect to get single digit kilometers added to the range, while on a cloudy winter day you won’t get even a full kilometer added.
They do make some sense on hybrids, as they are lighter so the range increase is a bit more and people are less likely to charge a hybrid. But, they still suffer from not adding much range, while adding cost, weight, and complexity.
Edit: Auto Focus did a re-review of the Fisker Ocean, which has solar panels. Linked to the timestamp where he is talking about them.
Bear in mind also that the extra weight and possibly aerodynamic compromises actually reduce range. In some cases, particularly at night, in poor weather, and at high speed, the panels would be a net negative.
They would only be useful if your car sat around in the sun for long periods without access to a charger.
such as parked at work or in a summer traffic jam?
Parked at work it will probably have a building nearby that creates a shadow. In a traffic jam, assuming perfect sun conditions and no shade, a 100W panel will generate around about 500m (or yards) of range per hour. Meanwhile the AC will use about 700W to 1kW of power to prevent your face from melting.
Some tests on YouTube report a realistic addition of 1 mile per day using the car in a typical commute.
Depending on the car and the temperature, AC Is simply not an option (same for heat) in a traffic jam. I drove a 2019 Nissan Leaf (with 12/12 battery bars and normally 80-140 miles in range, depending on the season)for my 19 mile commute for a while, and had an awful time during subzero temperatures (~-20 Celsius) once. I went from fully charged on the work chargers to considering breaking out my reflective emergency blanket in three hour stop-and-go traffic so as not to kill my battery before home. I stopped to charge and it took much longer than usual, to the point that I just gave up and used my hand warmers and hoped on the way home.
I don’t blame the car for that, I was unprepared for the predictable consequences of cold temperatures on electric cars, but it was still super unpleasant.
Leafs have battery packs with no active heating or cooling, which significantly impacts their performance in bad weather and when fast charging. Coupled with very small packs in the early models, and you have a recipe for a bad experience.
You’re better off putting the panel somewhere where it always gets sun, and isn’t extra weight you have to haul around.
Solar cells on a car have no real use. You would have to leave the car out in the sun for weeks to months to charge it up just once.
Seems worth offering as an option. If you can get 10-20 kms out of the solar panel in decent time it might be enough of an emergency precaution to give people who live outside of cities less reason to poopoo EVs
More like 5-10km, and then only on a sunny day in the sun, which would make the car uninhabitable due to the heat.
Better put a few square meters on the roof and use those instead of the 2-3m² you can place on a car at suboptimal angles and with the requirement to park in the baking sun.
There’s two problems with this:
Panels are not free. They cost money to install, weight to move around, and prevent you from a mega-sunroof that most EVs have.
Second, if you think one inconvenient charge per month will make people outside of cities and disparage (for whom EV already offer the most advantages) change their opinion, I think you will be disappointed. Most of them formed their opinion by “but I don’t wanna!”, not by any logical thinking.
This is the exact type of gimmick/bullshit they can utilize to convince people to get over irrational fears. Because people are often irrational when making decisions.
But its also tied directly into the fear of running out of juice in the middle of no where. It not only offers but actually gives people comfort and security. Even its really not meant to actually be used regularily or ever really.
I know one mechanic who has both a Model S and Leaf. He HATES that his model S slowly drains the battery when not used and his leaf does not. And he can explain the difference both why and how. If a company just used that fact to sell their car over any car that also loses charge sitting unused they will absolutely have an advantage for people. Imagine parking your car for weeks and it always being as charged as you left it or more instead of sometimes having to worry if you have a dead car waiting for you because you realized after the fact that you left it with a low charge
I absolutely do think it will change enough minds. I work in the industry from the repair side. But also with people who use their vehicle to pay their wage. I know this can work towards removing that part of the equation because there is a TON of people who dont want EVs to replace ICE and they stoke every dumb fear people have. Having the option, however poorly it performs has always been a net postive as long as it does perform the way its supposed to
Good sales people try to understand what is preventing people from making good choices. Bad ones just lie to you.
Additional costs are exactly what people expect to pay extra for ask in think that’s really a moot point beyond getting the amount in the right ballpark.
I appreciate the long form reasoning, but I disagree. People I’ve met that don’t like EVs, they don’t like EVs first, look for a reason later. There is of course a tiny, minuscule minority that do more than 300 miles of driving a day and cannot spare 15 minutes to charge, but that is well under 0.1% of drivers.
Never said it was people who drive high kms a day that has these concerns.
Seems to me we arent disagreeing on reasoning but about different situations. Such is the way of not speaking face to face though.
If it helps im not just making shit up, i deliver (ive moved up and am low level.operations now) autoparts to repair shops and have heard these complaints for over 10 years.
Its actually quite fascinating how often people drop the concern im trying to discuss once they start using an ev, or personally know someone who has one and they get encouraged by their persons lack of concern about losing a charge.
I think i wouldnt pay extra for the solar panel version if it was a significant extra cost but Maybr if it wasnt too much. (15k for full.self driving which doesnt even transfer to a new owner put the brakes on the failing enthudsiasm i had with tesla when model s was new)
While that might not be economically feasible, I’ve always wondered why plug-in electrics couldn’t send power back into the grid. No solar? Send energy onto the grid during the day from the car and recharge during the off-hours at night. Solar? Recharge during the day and send energy onto the grid at night. Just make sure to set a minimum charge that will get you to a charging station.
IIRC some car batteries can be used that way, but it wears out the battery.
For LFP batteries it’s irrelevant. They have a 3000 cycles to 80% cap, some of the new ones have 6000. That’s 10 or 20 years assuming full discharges an recharges everyday.
Or in terms of lifespan, assuming a realistic 400km range (250 miles), it’s between 1.2M and 2.4M km before the range reduces to 80% (750k and 1.5M miles). The car will be completely Theseus-ed at the point.
Some do, but to do this, the point of entry to the grid needs to be set up in such a way as to support this, with an automatic transfer switch for when the grid disconnects, and a meter that reads energy use as both incoming and outgoing, rather than the default of all incoming.
Source: am electrician who has installed batteries on peoples houses
What I have seen previously is that the amount of energy you get from the solar cells that you could fit on the top of the car is really small compared to what it takes to charge the battery.
Since there is minimal benefit, and it’s costly to include them and wire them to the battery, it hasn’t been viewed as worthwhile.
Spot on.
Rough summary of when it is energy and effort efficient: https://xkcd.com/1924/
For comparison, my rooftop solar array, with around 16 full-sized panels (~6kwp) produces just under 2 miles per hour in my electric car (around 3.3kwh/mi). Or in real life, takes about 2 fully sunny days to produce the power to charge the car.
What kind of ev are you driving? That’s insanely high energy usage.
My EV gets about 6km per kwh (around 4 miles)
You get 4 miles per kwh and they get 3.3 and you call that insanely high? The 2.5-4 mile to kwh is really standard for EVs. I don’t think the 3.3 is outside of the norm at all.
Fish reversed the numbers. It should have been miles per kWh
I don’t know anything about EV efficiency, but the rates are inverse, so they are drastically different.
Fish gets 3.3kwh/mile
Peacock gets 4 miles/kwh or 0.25kwh/mile
Oh I see that error now. I guess I just assumed from context his 6kwh panels generated 2 miles per hour. I get the confusion though
I’m still a little confused, wouldn’t 6kwh provide roughly 12 to 24 miles of driving range?
They mentioned their car uses 3.3 kwh per mile. With their solar setup they can generate around 6hwh per hour. Meaning they can generate roughly 2 miles every hour of sunlight.
Yeah this is what I’ve heard as well. Aging Wheels goes into it a bit in this review of a concept car, kinda neat - it has pedals like a bicycle but the energy they add is a tiny fraction of what the thing needs to move.
Edit: oops, I’m combining two of his vids in my head, this one is just solar not pedals.
it has pedals like a bicycle
Are you taking about the Aptera from the video you linked?
If so, the Aptera doesn’t have pedals like a bicycle. It’s a fully electric vehicle (or it will be if it reaches production).
Ah crap, you’re right - that’s another video of his, apologies
The amount of power you could pull from a single square metre of solar on the roof wouldn’t increase your range meaningfully.
What it would do, is that you could possibly keep your starter-battery from going dead-flat if you left your car alone for a 1/2 month, in the summer ( snow would cover it, obviously ), & since bringing a lead-acid battery to dead-flat permanently-damages it, this would prevent costly problems for the car-owners.
( this happened to a friend with a Prius: had to replace the battery, and the damned thing was inside the rear wheel-well??? in a little compartment.
Origami-engineering’s … simultaneously incredible & stupidly-frustrating )
I’ve held for years that they should be doing it to keep the starter-battery trickle-charging, but … why make the customers have fewer costly/frustrating problems?
Aptera is doing this with custom solar cells and they claim it’ll provide up to 40 miles of range per day. https://aptera.us/
I was about to say that. The main reason why they can do it is that Aptera went great lengths to make their vehicle as light and efficient as possible so what little charge they get out of the panels will make a noticeable difference.
This is a stark contrast with the other EVs on the market that are just huge heavy bricks on wheels that compensate for their inefficiency with bigger and heavier batteries.
To put this in perspective… The Aptera claims it with charge at 13mph on level 1 charging. This means if you plug it in the a regular wall socket, you’ll get 13 miles of range per hour.
The full solar package(~2000 dollar add on) get 40 miles of range, per day, under ideal sunlight exposure. That’s roughly a little under 4mph of charging. With a purpose built solar setup, which covers the rear window and even puts solar panels on the dashboard.
The Tesla model 3 gets something like 4-5mph charging on level 1. The full solar package from Aptera might be able to add about 8-10 miles per day in ideal conditions.
I’ve been following them for a while now and hope they can make it into production. Their focus on efficiency and repairability is quite exciting!
Because the aptera is ridiculously efficient and they cover way more than just the roof with the panels. I love the car, but it ain’t something I would consider mass market.
Plus, this again assumes you park it in ideal sun conditions, sun directly overhead (for the panel inclination), no shade anywhere around etc. Famous “up to” values.
The new Prius Prime has an optional rooftop solar panel.
According to an article in Slash Gear you can get about 4 miles of range after 9 hours in the sun.
So it has the potential to marginally increase your range on the scale of a short commute under ideal circumstances, but it’s not much apparently.
Thanks for posting the question! Whole point of the community.
I think we’ll see more of this in the future as they continue to make progress on inexpensive “solar paints” and the like. It’s not a bad idea, it’s just that the tech level doesn’t show much bang for the buck…yet.
Look at the Fisker Ocean, it adds almost no range or energy, and leaves horrible and distracting shadows on the passengers. Youat as well ask why you can’t charge a car with a D battery.
The first generation Hyundai Ioniq 5 had solar roof (at least some models).
The first gen ioniq 5 also had a very low payload capacity, with stories of families who couldn’t legally be in the car at the same time without being over the capacity.
The reason, I’m told, is that supporting the solar roof reduced the payload capacity a lot.
Also, solar cells on a car doesn’t make much sense like others have already said.
Because it barely matters. Like putting an extra AA battery in the glove box.
Well now the question is why they don’t put an extra AA battery in the glove box.
Then you can use your glovebox battery to jump your main battery when you leave the light on!
The materials are more expensive and heavy than what car roofs are normally made of, and the charge they would generate is miniscule. It may not even offset the added energy needed to move the car because of the added weight. Particularly if you live far from the equator, or somewhere cloudy, it’s probably not worth it.
When I was a kid (in the early 00’s) there were solar cars on TV and they were always these absurdly shaped pancakes made of ultralight materials and couldn’t even reach road speeds. I’m sure the tech has improved since then, but the real innovation that made electric cars possible was batteries. It’s hard to generate enough energy on the same platform you need to move without it being too heavy.
You’re absolutely right - still absurdly shaped pancakes and they can’t reach highway speeds when powered on solar power alone. They do reach road speeds nowadays but they’re allowed to charge during and after race time (regulations are pretty confusing). I was on a solar car team a few years back.
There are some, but as mentioned several times, the traditional car is too heavy for solar panels to be effective. There are some vehicles that are essentially enclosed motorcycles like the Aptera where it can be effectively used, though. Aptera can use solar panels effectively because even at their largest battery capacity, it’s still significantly lighter than an EV sedan.
The Dutch have been working on this for ages : https://lightyear.one/
The same could be asked with smartphones.
Why don’t smartphones include solar panels on the back side of the phone?
We buy solar phone chargers for use in the backyard. They work ok. It would take a long time to fully charge, but it will keep you from going empty.
Do you usually use your phone in the sun or leave it exposed to direct sunlight?
Well, it lays on tables a lot, with the backside facing up.
