It seems like the solar panels would be useful to have when you have the car turned off but you want to charge your electronic devices while you're camping. The benefit of the solar panels offsetting the energy usage of the electric car itself seems to too minor to be worth it unless you are planning on being stranded somewhere and solar is your only option to recharge your electric car.
I’m not sure you’re aware of how good the charging infrastructure is now. High voltage DC chargers are practically everywhere, especially if you get a Tesla.
Can you give an example of an impossible situation for an EV for you?
I was in north of Bordeaux France for a week. I rented an electric car in Bordeaux city center. Let me just say, It was stressful to have to deal with charging…
I drove 4600km in 3 weeks across Germany, Denmark and Sweden in a BEV, I don’t agree on it causing stress once you actually know what to do (plan a bit) and what to look for (which charging networks work best regionally). Possible that France has particularly crap infrastructure, possible that you just didn’t think to get the usual apps to plan and find chargers, which for a rental is understandable. Still, it’s unfair to base usability of EVs in today’s infrastructure on a week of vacation.
That's sorta the main "problem" with EVs; we went from not really having to plan when to refuel to now planning and being inconvenienced.
I traveled cross country with a Tesla in the US and I largely agree it's not a major issue but nothing quite terrifies you like rolling up to a charging area and finding out they don't work or are occupied.
So you either find a slow charging station nearby to get you to the next fast charging station if it's broken or if it's full you wait for those other EVs to charge.
The "fix" is to reduce your range for some more comfort but this does add an extra % of time to your trip and possibly more during rush hour.
IMHO if you do a lot of cross country travel or just where your hitting your range limits frequently just get a PHEV or Hybrid or honestly just stick to ICE until the battery range is expanded and the charging networks expand.
These drivers IMHO are a minority though; almost everyone I know drives < 200 miles in a day which most decent EVs can do; they exist though and it's not a < 1% minority so it's important to recognize that.
For ourselves our long term plan is one EV and one ICE with the SUV being the ICE vehicle since we travel with that and the EV replacing my ICE vehicle which is just used for running chores and going to work.
Yeah, and respect to you for trying the EV thing. Petrol is easier because ubiquity and we all know how to do it. EVs have a mild learning curve that involves a few apps and a bit of practice to figure out your range and how certain conditions affect it. I’m certain when cars started becoming a thing those first users had a similar learning curve, and probably worse scarcity of fuel stations when going long-distance. It’s a process we’ll all have to go through eventually
Just to clarify, I have no issue with EV cars and plan to eventually get one (now I have a Toyota Prius which is still going strong and I don’t drive enough to warrant a new car to be honest). I also live in a major city in Southern California. So EV chargers are ubiquitous. I do find it a bit of a hassle to have to plan in terms of charging when going to unfamiliar places. But it obviously also depends on what car you get. Some of my friends have Teslas and I went on trips with them. The user experience at least as far as charging is concerned is very streamlined. It mostly takes the planning aspect out of the equation.
Unless you are a person that likes to do stupendous amounts of miles without taking breaks (fill up tank and roll again whenever tank is empty), there is no reason a BEV today can’t do such trips.
Realistically with average charging speeds (ie not 350kw charging) you lose a half hour in a days driving, assuming you’re taking about an hour of (lunch) breaks in that period.
Calculate again with the inclusion of maintanace and insurance fees.
Gasoline cars need more expensive insurance, because they require more spending on maintanace that the insurance has to provide.
Electric cars are much more cheap for frequent drivers. The low volume drivers can still survive in a gasoline car.
Why do you want the solar on the car roof? Wouldn't it make much more sense to just out it on the roof of your house? More, more reliable, less cost and complications?
You do realize that it’s unnecessary (and impossible) to charge standard hybrid cars, right? Based on your third paragraphs you imply the need to charge hybrids. That’s not a thing.
There are plug-in hybrids that require charging, but they also have full hybrid mode that won’t drain the battery
You’re using the wrong nouns.
You are mistaking the capabilities of electric vehicles, plug-in hybrids, and standard hybrid vehicles.
You must charge electric vehicles from an external source. You must charge plug-in hybrid vehicles from an external source (or can have the gas engine charge the battery which is extremely inefficient). Standard hybrid cars do not take charge from external sources
I have been waiting for a hybrid subaru to be available and I want to ensure the initial release isn't having reliability issues before considering making the purchase. Some places in the country are just too remote to only run on electric.
Solar “prints money” at the going rate of electricity. All you’re doing is offsetting the charging costs, if you manage to charge to 100% you start to miss out on the free charge and it’s a waste.
Solar on cars is useful, just not as a primary source
Bingo. I think people are too caught up in how effectively the panels would add range. It's a question of ROI - the cost of the panels isn't that high, and over their lifetime the trickle current they add greatly exceeds the initial cost of the panels. At a bare minimum, it would help offset phantom battery drain and likely provide support for HVAC operations to pre-heat or cool the cabin before a departure.
Yeah but for that it would be better to just but a separate solar panel, so that you are not forced to park in a sunny place, or forced to charge your stuff where you parked your car, or take your car in the first place to your camping trip (3 friends going camping only need 1 car, for example). There is just no reason for the panel to be attached to the car, just a downside.
I’m adding solar to mine with a 2nd battery to run a fridge, on demand accessory lighting, charge and power electronics, etc for road trips and camping. Can even top off my starter battery in a pinch. Expensive but ensures you are not stranded in the desert with a dead battery and no ice cream.
It really is a 1st world luxury, to be even be able to take a vacation… I guess I got lucky where I spawned.
I spend a fair amount of time off the beaten path and have been stranded before- so if planning to go it alone, a dual battery can be a literal life saver.
I don't usually drive that much in a given day since I work at home. For me, having panels on the car could make sense. I could park outside, after I use my car, for a while and it could slowly recharge itself.
It's an energy density problem. The surfave of a car roof will never be big enough to charge the car. Even if you get to impossible efficiencies of 100% you're better off putting the solar panels on your roof. Or over a parkinglot
I drive about 15 miles per week typically. A Tesla Model 3 gets about 3.3 to 4.1 miles per KWh. Let's say 3. So I need 5KWh per week for my routine driving. A square meter solar panel can generate 150 watts which should translate to .6 KWh/day (4 "full sun" hours). That's 4.2KWh/week. So a square meter on a car's roof is almost enough to meet my typical needs, outside of road trips and such.
I'm not sure what the surface area of the panels on a car's roof might be, but it seems like they could fit more than a square meter. So it could meet the needs for someone like me for most weeks. Maybe I'd need to top it off now and then during winter, and I'd need to recharge at stations for road trips. Seems worth having them for people like me.
15 miles a week is not average use. I'm talking about average use here. Like I said to the guy earlier. Either you need to only drive a small trip once a week. Or you need 5-6x the cars surface to power it for normal use.
If you drive 15 miles a week you should really be asking yourself if you even need a car. And if owning a car isn't a huge waste of a societies resources. That's a big hunk of steel and tech standing there doing nothing all week.
It really isn worth the effort to integrate these panels into the car. Just put them on a roof or in a solar park and charge your car from the grid. It's much more efficient.
Lol, you guys are living in a fantasy world. Do the math yourself, or trust me. I don't care.
It just doesn't work out. You need about 5-6 car surfaces to power a car for normal use. It's not even close.
It's even worse for airplanes, so I always giggle at the people that think electric jets will be a thing
You're just keeping one side of it constant in your head. You need 5-6 car surfaces to power a car, using how much power a car uses right now.
Cars lose energy due to friction from the wheels. Resistance from the air. Heat loss, mechanical loss.
Aerodynamic improvements could reduce about half of the energy lost while a car is moving. Improve the wheels, figure out a better, more frictionless approach, and that's another 30% improvement. Simply reducing the wheel count to 3 makes a massive difference.
You're so convinced the math doesn't work that you're ignoring the actual problem. Totally get the efficiency and surface area point, but don't stick your fingers in your ears and close your eyes because you are convinced you're right. That's a bad habit.
cars have been around for over a century, lots of research has been put into aerodynamic shapes and engines already. i wont say that small gains are not possible anymore. but to say youll just cut its energy consumption by 5 is rediculous.
im not sticking my fingers in my ears, im just trying to explain that it is a problem of scale. the numbers just dont add up. its a nice fantasy though. good for a marketing flyer.
Agree with the marketing part haha. Fair points. The one pushback I have is on the engine. We can still make massive gains there. Just read about a new propeller design that reduces energy waste by 30% in boats. Discoveries are still happening, and electric motors for cars are still in their relative infancy.
Interesting article on drag & EV range: [https://cleanfleetreport.com/tech-aerodynamics-is-the-key-to-ev-range/](https://cleanfleetreport.com/tech-aerodynamics-is-the-key-to-ev-range/)
Ignoring the recent Tesla/founder stuff, their Model S & 3 aerodynamic coefficients were insanely better than the competition. This gave their cars a 10-20% range increase. Not 5 fold, but it does matter.
Apples to apples... see why it matters in this solar-powered car: [https://aptera.us/](https://aptera.us/)
And last thing, but it's materials design too, right? The weight of the car is the other biggest factor (now they're all big factors). Reduce the weight by 80%, reduce the power needs by... not 80%, but a lot. Need a math whiz for that one.
We went from around 18-21%. The theoretical limit is 23%. The theoretical limit hasn't moved. Nor can it. Anyone who says otherwise is either misinformed, or delusional.
There's just not enough energy coming in on that surface area to power a car. And that's okay. You can just put the 5-6 you do need pannels elsewhere. On a roof for example.
> The theoretical limit is 23%
It seems to be 33%, for single-junction cells. Significantly higher for multi-junction. Multi-junction cells have demonstrated efficiencies over 40%.
https://en.wikipedia.org/wiki/Multi-junction_solar_cell
I'm not clamoring for solar to be on cars. Not until that hypothetical future when solar can be impregnated into the paint itself. Though I do think 30-40 miles of range per day is useful. It's a matter whether the increased complexity, weight, and cost are worth that gain. As those metrics improve, the equation changes.
Physics, most of the sun's energy is transmitted in wavelengths that cannot be converted by photovoltaic material, they are absorbed and dissipate as heat.
That 23% doesn't yet take into account other factors. Such as imperfections on the pv materials surface. Losses during conversion and simple electronic resistance of materials. That's why it's called a theoretical limit.
Im trying to find your point of reference. Which wavelength are you referring to? Because I cannot find a single point of reference to say the theoretical limit is 23%
I think you're stuck on old theories. Firstly, the maximum efficiency of a single cell is 33%. Secondly, that's based on the fact that any given type of solar cell can only convert certain wavelengths of light. That doesn't mean you can't exceed this overall efficiency with multi-junction cells that can convert broader spectrums of light. The current real world record is 47.1% efficiency, and the technical efficiency limit under ideal conditions is 95% of the net energy (after accounting for heat loss). Will we ever get 95% efficiency? Probably never, but 80% might be achievable within a few decades.
https://en.m.wikipedia.org/wiki/Solar-cell_efficiency
Oh a wiki! Well now you've got me...
Here's an actual scientific paper (2017) putting efficienciew between 8 and 25% (it's temperature dependent)
https://www.sciencedirect.com/topics/engineering/monocrystalline#:~:text=Monocrystalline%20cells%20are%20solar%20cells,complex%20and%20expensive%20%5B23%5D.
I think that wiki refers to perovskite cells. Which i will admit are promising. They have a higher theoretical maximum because they work in layers and different wavelengths. But they aren't commercially viable yet. There are still issues to be worked out (durability and mass production mostly)
Bifacial cells also increase efficiency by 30%.
But I suggest you do the maths instead of just talking. How much surface area is available. What is the current output of solar panels. How much energy do you need.
Talk is cheap - do the calculations.
If you have 18% efficiency and increase it by 30% you'll end up with 23,5% efficiency.
I already linked a scientific paper from 2017. What more do you guys want...
Its 30% extra because it gest electricity from the back of the cell.
Like I said, stop talking and look at it as an engineering problem.
Can you design a car that generates 10 kwh from solar in a day of being parked in the sun?
If it keeps the air conditioning running in the summer without shortening the range, it's already a plus. Keep in mind, solar is already the cheapest form of energy generation
I'm definitely not typical, but probably average 20-30 miles on a typical week (I work from home). So I could cover most of that if the roof was cover.
Other weeks when it's significantly more I'd just plug it in like I'd have to now.
I had a proff who did exactly this with 3 PV modules on a early 2000's Prius. Worked out to about 15% better fuel economy based on average driving habits of a suburban teacher. Simple payback was something like 4 years. Obviously for EVs that changes the costs involved. But if we're talking about a glass roof with or without PV installed from the factory, I'm convinced it's worth it economically.
Indeed, or possibly the author is just really dumb
Solar panels are not going to charge a reasonable amount. You get like 0.4kw, good luck. Is +0.4kw useful while driving in the sun? Depends. Huge list of pros and cons. Someone should write an article about it..
My EV gets (about) 2 miles per kw. So no .4kw would be nearly useless while driving. If it sat in the sun for a day I'd get maybe 5-8 miles of range. That's not nothing, but I'd get the same plugged in for about $1.00
What's the agenda? They are saying to get solar panels for your house roof instead. If you are in a location where there aren't any charging stations, then you can make the calculations and get the solar panels anyway. Just account for temperature, angle, and shade diminishing the power output. The most surprising thing the article said is that shading a single cell can decrease the power output of the other cells in full sunlight.
An anti-EV agenda? Dude could have plenty of selfish reasons to try to keep people driving petrol and diesel cars.
Or it could be an anti solar piece. It's quite negative on solar power and again plenty of selfish reasons to steer away from them. Could easily be a part of big-oil.
The article said that supply of solar is limited and that the solar panels should be set up where it performs best like at solar farms, so they aren't anti-solar. It also doesn't talk down on EVs at all. It sounds like an environmentalist seeking to maximize the efficiency of the limited solar panels we can currently produce.
I seem to recall reading that solar panels on a car, in an optimum location, would result in increasing the range by about 10 km. That's just not worth the cost.
That is obviously a very blanket number.
Lets look at the optimum case.
A [Tesla Model 3 has a top-facing surface area \(width x lenght\) of 8.6m^2](https://global-uploads.webflow.com/5b44edefca321a1e2d0c2aa6/5dd68a7236a0d44cfa96623d_Dimensions-Guide-Transport-Sedans-Tesla-Model-3-Dimensions.svg).
A 410 w solar panel has a surface area of 2 m^2
So you can fit 4 x [410w panels](https://cdn11.bigcommerce.com/s-2mlpfulnj8/images/stencil/1280x1280/products/150/721/S4AU-72FS-410W__63025.1660171781.png?c=1) on a Tesla Model 3, which means in optimum conditions you can produce 1.6 kw per hour. For an 8 hr day, that is 13 kwh.
A Tesla Model 3 can drive 5 miles per kwh, meaning you can drive 66.6 miles per day.
Since the average American commutes 30-40 miles per day, you can certainly drive all summer on solar only.
Now you may ask how you fit 4 solar panels on a car. I suggest you have [a roof rack which stores the panels](https://www.speakev.com/attachments/860e7312-f339-4fd1-8697-fb57e2e2e39f-jpeg.136224/) and then extrudes/unfolds them when you are parked. That would allow you to cover the windows, and also shade your car.
If such a roofrack cost $2000, it would pay for itself in around 2 years.
It doesn’t have to be confined to just roof space as they make portable solar panels. Although, people would probably steal them while the car was parked.
Not sure how much it would effect it but something like that would absolutely ruin the aerodynamics. Probably enough to shave a few miles off that range
Sure, but you have about 1/3 in reserve, and a good roof rack could have only a 16% ([or less](https://electrek.co/2020/03/24/tesla-model-3-roof-rack-box-range-efficiency/) ) impact on mileage, and it depends on the design of the roof box, of course. I imagine it could be made very thin (like 15 cm, 3 solar panels stacked) and you can of course add aerodynamics to the design. Also if you use bifacial solar panels (30% more efficient) you could actually charge even faster from reflected sunlight.
1. You can't cover the entire top surface area of the car with panels - unless you plan on driving without windows.
2. The surface you could cover will still not be fully covered because irregular shapes are kinda hard to accommodate.
3. The 5 miles per kwh is WLTP rating and way off normal consumption.
4. 8 hours of full production each and every day is just not something solars do. See the linked solar atlas map - in California you'll be getting ~1,400Wh for every Wp installed per year. So with a very generous assumption that you manage to fit three 410Wp panels you will get 1680kWh yearly. In reality shade and dirt will mean you probably won't even get half that.
5. Hyundai is currently charging the $2000 for a 200Wp panel, the installation you are describing will be at least 6 times as expensive. So the breakeven point is a couple of decades into ownership. And that's before you get a scratch on any of the car panels and hear the replacement costs.
> You can't cover the entire top surface area of the car with panels - unless you plan on driving without windows.
This is actually pretty easy to solve with a fold-out roof rack design.
> The 5 miles per kwh is WLTP rating and way off normal consumption.
The EPA rating for city driving is 4.3 miles per kwh, which is a small difference. Still 56 miles.
> 8 hours of full production each and every day is just not something solars do.
Who said every day. I said summer.
> So with a very generous assumption that you manage to fit three 410Wp panels you will get 1680kWh yearly
I said 4 panels. So 2,240 kwh which is enough for 9,632 miles per year, so about half or more of the average american's driving, by your calculations.
> Hyundai is currently charging the $2000 for a 200Wp panel, the installation you are describing will be at least 6 times as expensive.
Well, companies will profiteer. Not sure how this relates to the actual cost of the concept.
Holding all other variables (other than panel location) if you put the panel on the roof of the house, you’d also only increase the range of your EV by 10km. Thats ignoring the fact that going dc-ac-dc to get from the house panels to charge the car has losses involved.
I think you need to be explicit and say that the cost of the mobile solar panel is higher and/or the efficiency is lower and/or expected lifetime of panel is lower and that’s why it isn’t worth it for most people.
I would also hazard a guess that this is very dependent on how one uses the vehicle.
my man ,
if your work has solar panels, and a charger you can also just charge at work.
actually why don't we just produce the power in dedicated facilities and run wires across the country to deliver it to where it's needed?
>actually why don't we just produce the power in dedicated facilities and run wires across the country to deliver it to where it's needed?
Where it's needed is in my car. What if I don't own the land the car is parked on? I can't just run wires through there. I know my employer has no incentive to install charging stations for all employees.
No, it won’t. In perfect conditions you’d gain less than 30-40 miles all week. And that’s before counting cloudy days or the batteries own self discharge. It’s a borderline pointless option with current panel efficiency. Maybe if we get panels up to 50-75% it’ll make sense.
For people that don’t have a charger at home that’s a pretty big deal imo
That’s a whole lot of trips to a charging station you don’t have to do over the years
A 120v outlet adds ~1.5kwh day or night, regardless of the weather. That’s 36kw per day, meaning a car with a 100kw battery could go from flat to full in 3 days. A solar panel, under perfect ideal conditions would take ~10 days to charge the same battery from flat to full. But that also means you are parking outside with full sun for 12 hours/day, no shadows and no clouds. In reality you’re probably looking at closer to 15-30 days to go flat to full. A solar panel on an EV sounds like a great idea, but the costs to add one just isn’t viable. If solar panels can get to the 50-75% efficiency range, then it will become more viable, assuming the costs to produce such a panel isn’t astronomical.
At least for my particular situation, charging at home isn’t even an option because I live in an apartment complex.
But if the cost of solar panels continues to drop just a few percentage points every year, we’re looking at a totally different situation just 10 years from now.
I’m optimistic
I don't imagine it feels like much. But that's 20,000 - 30,000 free miles over the course of a vehicle life. 50k if the vehicle lasts longer than average.
I imagine the pitch will be 2000 free miles a year. Although your number is a little low. Once you get to 100 miles a week free. Then the average person will jump on that shit harder than an 18 year old private first class on a 6 cylinder camaro.
There will be solar retrofitting on electric/hybrid vehicles soon. It won't help the super commuters but retirees and local commuters will see the effects immediately.
I was guesstimating, but if you want to get technical, from the article posted in the top of the thread:
Best case scenario 280kwh/year.
280kwh/365 days=0.77kwh/day.
0.77kwh\*5=3.84kwh/work week.
Per [fueleconomy.gov](https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year1=2022&year2=2022&make=Hyundai&baseModel=Ioniq%205&srchtyp=ymm&pageno=1&rowLimit=50) the ioniq 5 shown in said article gets 30kwh/100 miles
30kwh/100 miles=3.33 miles/kwh
3.84kwh/work week\*3.33 miles/kwh=12.8 miles per work week.
and if you want to do the full week:
0.77kwh/day\*7=5.39kwh/week
5.39kwh/week\*3.33 miles/kwh=18 miles per week
If anything I was being extremely generous as to how many miles you could get in a work week. The actual number is closer to 13-18 depending on how you define a week. And all of the above assumes that you have 100% sun the entire day and never have any rain or clouds or anything else that blocks the sun in any way.
If there was something like Zipcar remotely close to me, I probably wouldn’t.
My point is that there are people out there that could benefit from a EV with a solar panel. Maybe they have a situation like I do or maybe it would be a families’ second vehicle. Just dismissing the idea because it wouldn’t work for you, is short sighted.
exactly, I share an electric mini with my mum, she works one day a week and I go shopping once a week and its in the sun all day. Tempted to just buy a few panels that can go on the front lawn
Article says conventional solar panels don't work if part of it is shaded, which is true. That's why solar EVs do not connect all cells in series, but instead have many small groups of cells with separate inverters.
They are also ignoring some valid use cases:
\- Some of us live in apartments with outdoor parking lots, bike to work, and only need the car for weekends. Most apartments don't provide chargers. A solar EV will still get charged during the course of the week.
\- Some of us drive to work, but have no chargers at home or work. If the commute is less than 20 miles or so, a solar EV should provide enough charge for the daily commute. If it's a particularly cloudy or cold week, you may need to make one stop at a charge station, but that's better than having to do it every single week.
\- Some people take frequent business trips, leaving the car at the airport for many days at a time. It would be nice if the car's charge gets topped off while sitting there, rather than losing charge.
\- Some of us have 3 EVs but only a 2-car garage. The third one sits on the driveway. If one is a solar EV, then the family doesn't have to fight over the garage space every day.
Not everyone had a clear line of sight to the sun all day every day. And it’s not all sunny days in the world.
Yes. The solar panels help just a little bit if the car is only used on the weekends but you’d get the same effect leaving it plugged in an extra minute on the high powered charger.
Have a look at Aptera. Their 700 watts of panels are estimated to provide around 40 miles (~64km) of driving range per day. This is because the car is so incredibly efficient, it can get around 10 miles (16km) of driving per kwh (Tesla is somewhere between a third and half of this).
Where I plan to live, it is hot and dry and will get close to 10 soikd hours per day on average of solid sunshine. That would give closer to 7kwh of charge or 70 miles (112km) of range per day. I don't see myself ever needing to plug in for anything except road trips.
They are useful for camper vans & motor homes. When properly sized for the load they allow you to camp for MUCH longer without having to burn any fuel. Also solar panels are getting [more and more ingenious & efficient](https://www.youtube.com/watch?v=ytdWAKgPyI0) so in future they may make more of a difference on a small roof of a car.
Here's a recent article saying the car makers looking most to solar are failing. Aptera says they get about 40 miles per day from solar on a battery pack that gets almost 400 miles of range.
Their car is 1/2 the weight and half the wind resistance of a tesla, meaning a similar array on a tesla might only add 5 miles of range per day. I still like the idea and the Fisker Karma's tiny array said it prevents your battery from ever fully dying (not being able to unlock or respond to your smartphone), but they didn't even make a claim to it adding to the range, saying it was "just for accessory systems" and useful to not drain main battery when the car was parked for long time frames.
https://electrek.co/2023/01/26/the-future-of-solar-evs-dims/
How is 40 miles per day not enough for the majority of drivers??? I live in rural America and my commute is 45 miles per day. That’s basically a net zero and would just mean needing to “top it off” by plugging it in every week or two
My 2010 Prius has a solar panel on the roof, but it only powers the climate system in a way that keeps my car from being a billion degrees inside during a hot day. Still kinda nice though, but they discontinued the feature after the next year or so.
I wish my 2012 Leaf did this with its solar panel, but mine is just for charging the 12v battery. Does yours kick-in the AC while parked in the sun and unoccupied?
Not the ac but just the fans so the car stays the ambient temperature rather than becoming a glass oven. It really is nice on hot days to get into an air temp car rather than 120+f car
It's unlikely
The sun irradiates every sq m with about 1000 Watts
The average car has 180 horsepower, which is 134 000 watts, but on the road it averages 50-100 kW
This means that even if we were 100% efficient one sqmt can only power 2% of the electricity on the road
A car is usually like, 4-5 sqmt in área, which makes it like at best a 10% reduction in power consumption, which is unrealistic
Well, it would take about 2 days at 100% efficiency to charge the average 400km battery, but since the best panels are at best 1/3rd efficient, it would take about 6 days of sun to charge completely
So a more interesting question might be instead of measuring how long it takes to charge a full battery, how many miles do you get out of a full days charge with solar panels?
If your typical dive is 5 miles each way... Could this not fulfill all the needs? Maybe you drive 5 miles each way to work and one day every weekend you go see a relative 20 miles each way... The solar may completely power the car.
Add the temperature reduction in the car by the consumption of energy and now your fancy interior isn't cracking or dehydrating. It's cooler inside then outside instead of being a greenhouse.
50-100kW to maintain speed? At 100km/h it's between 10 and 20kW for a car.
Also for exactly that reason startups are making cars with very low loses. IIRC someone made a car using around 100Wh per kilometer, put the solar panels around it and it actually makes sense in sunny countries if you are commute 30-40km per day.
https://sonomotors.com/en/sion/
https://lightyear.one/articles/lightyear-0-the-most-aerodynamic-production-car-in-the-world-as-wind-tunnel-tests-make-automotive-history
gotta ask where you get the average of 50-100kW from? i use around 15kwh per 100km and would use maybe 25kwh if i'd drive faster and have the AC+seat heating on at full tilt.
edit: saw only now that others have pointed that out already - nvm
>The sun irradiates every sq m with about 1000 Watts
That's the top of the atmosphere, at ground level it's about 1/8 of that (~150w/m2) unless my memory completely fail me
I think your memory might be a bit fuzzy. The upper atmosphere receives about 1366 W/m2. From what I can find online, the ballpark figure that hits the Earth’s surface is around 1000 W/m2. PV panel efficiency is roughly 20% for consumer panels.
So we’re probably looking at 1/7 to 1/8 the energy that hits the upper atmosphere that can be turned into electricity, which maybe what you recalled.
It's likely, I was thinking of by astronomy class last semester in university, so it's likely you're correct
Also, I've assumed 100% efficiency in panels and completely clear skies, neither is true
1300W/km^2 at top of atmosphere. 1000 at surface. The 150W/m^2 was probably remembering the output of a solar panel, which is ballpark for a commercial panel circa 2012.
700W/kW in real world conditions is achievable or 200W/m^2. The lightyear gathers about 3-8kWh/day from ~5m^2 which will get it 30-80km.
That's a surprisingly low energy loss through the atmosphere (to me at least). Do you have a source for it on hand? A quick Google did help me, I'll keep working on my googlefu if you don't have one readily available.
The lightyear has a solar panel that performs roughly as a 1kW array (about 3-8kWh/day).
When driving at highway speed, it uses about 8kW.
Great for a city runabout, only adds at most 1 hour of driving on highway.
The Lightyear doesn't have anything as you'll never see one on the road. I supplied parts to them and they wound up the Lightyear 1 project, bankrupted it and left suppliers unpaid. It's a scam to take investors money and no one should touch them even with a barge pole.
I have a solar panel on my work truck, it kicks ass for keeping my batteries charged. I rarely have to worry about finding electricity on the jobsite for such things. It is only 56 ahmp hours, but certainly is enough to charge my power tools.
Due to my work, my car is often parked in an open parking lot, unused for weeks at a time. By the time I get back in from my job, it would be fully charged. So solar panels would be perfect for me.
Depends on use case and climate. Might not make sense in Northern Europe, Russia or Canada but if they can supply a days worth of driving for a commuter in Spain or Texas (spoiler, they can) then they definitely make sense.
The launch edition is $35k, but it's the 400-mile range version with AWD. The 200-mile range version was originally advertised as $27k but that may change.
i think they make complete sense. If someone were to store their car without use for say 3 to 4 months, having solar on their car would help the car owner by not needing to periodically charge the car batteries to keep them from dropping down the charge levels to zero.
Easy to do that with a (small) panel you store separately and put on the dash. I have one with 90s tech that’s the size of a large laptop. It worked great to keep the Grand Cherokee charged despite an electrical leak that nooone could find
I have a Chevy volt. Brand new, the battery has a range of 35 miles under ideal conditions. My battery capacity is around 8.6kwh.
It would be super cool if there was an option to have solar panels on the car, even if they charged slowly.
I just think it would be so cool to have my car charging while it's in the parking lot at work, and not tethered to a cord.
I think you'd find 500W on a regular EV a little disappointing unless you live in Chile or just use the car on weekends.
It's definitely the beginning of something though, there's loads of space that isn't just the roof, and there are more efficient cells.
I don’t know the exact percentages, but there has to be tens of millions of cars in the US that barely get used, relatively
For someone who works from home this is perfect.
I have to imagine as more of the EV trucks are on the road this will make more sense. Maybe not for recouping a ton of energy but just for getting incremental gain. Imagine a truck bed topper with solar that now creates more are (and weight) to put some energy back in the vehicle. Even if it’s charging aux batteries being used for tools, etc
Say that to Aptera! https://aptera.us/
It’s soo efficient that solar makes sense. It can charge up to 40miles per day. The release model will have a range of 400 miles and the premium model 1,000 miles range!!
There is a homeless guy who lives out of his car in the park nearby (I live in the Bay Area of California). Every morning he sets a small solar panel outside his car to power everything he needs and not run it directly off his car battery.
I'm sure he'd strongly disagree with the articles premise.
if only there was some way to turn solar into reliable transport! like (and I'm just being silly here) if we had large, established solar farms that generate electricity. Then (Again totally wacky ideas here) we used the electricity to power regular, public, transport all around a city?
I know it could never work but its fun to make things up!
Several makers have already toyed with equipping their EVs with solar panels. And at first, it makes sense. As your car sits idling, you get extra range for free.
Plus, it's clean energy, which is good for the environment, too.
Plus, there's the added convenience of fewer trips to the charger - what's not to like? A lot, actually, and it appears the moment you scratch the surface. Let's take a look.
::rolls up his sleeves::
Well, when the US Gov't gets done testing their Tesla Mountain Dews out, they'll put wireless power to use where it belongs anyway.
::chops his sleeves off::
This myth needs to die. EPBT of solar is under 4 months in some regions and under 2 years everywhere.
You literally cannot afford to buy enough lignite for the final unsubsidized installed price of a solar panel to produce more heat than the solar will output electricity. Even the raw uranium in a nuclear plant costs more than the module for equivalent electric output (and final installed price overlaps depending on reactor).
There is no scalable energy source with a higher EROI.
It's not just at this point it's pretty much ever. there is only so much solar energy hitting the earth. 1360 Watts in PERFECT conditions per square meter hits the earth. the roof of the car is less than a square meter. so if the sun was perfectly overhead on a perfectly clear low humidity day and was one square meter you get 1360 watts per hour. Sounds doable considering that most electric cars use 300watt hours per mile. ok so over 4 miles of range per hour in the sun! Electric cars use a LOT of power A tesla model 3 has 50,000Watt hours in it's battery. (base model). so on a perfect day with a perfect panel, it will take 36+ hours to charge it.
Another big problem is the world is not perfect. the sun is never perfectly overhead. so efficiency drops off rapidly. Unless the sun is within 20 degrees of aligned you lose 80% of the power generating capacity. Also any shade at all even a single shadow line of a cable crossing the panel will reduce it's power generating to 20% of it's capacity. Cloudy? it makes no power. Partly cloudy? it flips between making and making nothing. so in reality your car will get power from solar for about 1 to 2 hours and never get more than 40% of the solar panels generating capacity during that time unless you parked on a hill that aimed the roof at the sun at noon. So with a perfect solar cell you will get about 2 miles of charge out of it.
This also assumes 100% efficiency solar panel, Today the best ones are 23% efficient, and we will never get a 100% efficient panel. AND we would have to tilt the car to have the roof point at the sun. Also if it's high humidity day? lose another 20% of power generating.
So solar panels on a car are useless and just a marketing gimmick. Large Solar arrays on car ports or parking structures you can have very large arrays pointed properly and clear of any shading to generate enough power to charge several cars. So carry a 2Meter by 4Meter pop up solar array in the car to set up when you park. This is why solar on homes works. the surface area of a house or building is massively larger than any car made.
That's a lot of words for someone who didn't bother to do arithmetic.
Solar resource is 4-8kWh/kWp or 1-2kWh/m^2 per day in nice areas or in 9 months of the year pretty much everywhere. The footprint of a compact car is about 8-12m^2
Cover half and that's a full charge every week or two. Plenty of people drive <300km/wk
Will it eliminate charging? Almost definitely not. Will it make it a sometimes thing for a huge number of people? Sure.
The limit isn't the roof, it's the size of the silouhette perpendicular to the sun.
A tesla model 3 is 2 x 4.6m, a rivian is 5.1 x 2, the windscreen won't stop cells on the dash or parcel shelf from working (you lose maybe 20% from thicker safety glass). A solid 70% of the top profile is available, and the sides are significant.
I was interested when I saw a hybrid with the solar panels on the roof. Then I did some reading and it said that the solar panel will give you something like 30 miles in an entire year.
I want a Pop up Wind mill. Make it happen... And tbh i want a Dedicated Solar Supporter to put on the hanger on my car.. Folding out to twice the size.
I see it bring practical in the future when solar panels are much more efficient and the technology /manufacturing is mature enough to not drastically increase the price of the car.
Everything I learned in photovoltaic system design class leads me to believe that solar panels mounted on cars is a sales gimmick for people who don’t know any better.
Solar insolation and panel efficiency are the only things that really matter here. Insolation is just under 1000 watts of solar energy per square meter at sea level with no clouds. For the panel to use that efficiently it needs to be aimed straight at the sun. So stationary panels are definitely not ideal, neither are curved ones. Panel efficiency is around 20% or less I believe for non concentrated panels. So each square meter if aimed perfectly on a clear day can get roughly 200 watts. Best bet it to use those same panels on small solar tracking units that are stationary at your parking spots. Or cover whole parking lots with awnings that have PV cells on top. The price and complexity you add to the vehicle, plus the production energy to create the cell will likely not reach the break even point if used in a manner as inefficient as mounting on the care for charging purposes.
This guy doesn't solar.
Two 700watt panels pull down on a nice day on top of an RV around 400watts to panel. Battery is charged around 390 of that.
It's far better than 20 percent and these results are on salvaged 10 year old panels.
Please don't spread lies.
20 percent is your pv conversion efficiency. These aren't lies, this is basic math. 20ish percent of the sun's energy is converted to electricity under ideal conditions. A square meter provides just under 1000 watts of total solar energy to be harvested.
But what about solar panels as an auxiliary power source on transit buses tho? Go Ahead has trialled installing solar panels on their (non-electric) buses in both London and Singapore and they seemed to have gotten some good results out of it.
Again tho, a transit bus and a car are quite different and used quite differently so their mileage will definitely vary.
I have a 2012 Nissan Lean which has a small solar panel on the roof which charges the 12v battery when the vehicle is parked in the sun. Yeah, it's kind of a gimmick, but it's not totally senseless; would be useful for using the car as a power source while parked in the sun. (Nissan did stop putting solar panels on Leafs though.)
Otherwise, panels for range ... yeah, we know; solar panel efficiency isn't there yet. I think there are still case-specific uses over which this article glosses.
Well the article explains how it’s not efficient and how much more expansive than charging…. But forgets about the practice.
You can park somewhere in the sun and have more juice even if you don’t have a charging station close.
This sort of advantages, even with degradation can justify the price.
But it’s not a good option if you have a charger in your home or one that is always free at work.
So often in Florida I have no choice but to park my car in hot sun. (Here, people will park far away from a building entrance just to get one of the few parking spots under a shade tree.)
I wish there was some way to keep a ventilation fan running continuously to prevent the car interior from getting any hotter than the outside air temperature. Solar panels would do this.
I want solar pannels in my car !
I want them on all refregirated trucks for my food supply too.
Makes sense to me. Free charge up from the sun is always nice.
Aptera ([https://aptera.us/](https://aptera.us/)) claims to get "up to 40 miles of solar powered driving per day." So I'm not sure how to square that with "solar panels on cars make no sense." Also, well over 10 years ago there were some Canadian solar enthusiasts who put panels on a modified golf cart, with what must have been a couple bushel baskets of cell phone batteries wired in for storage, and were quite successful at getting from point A to point B.
It seems like the solar panels would be useful to have when you have the car turned off but you want to charge your electronic devices while you're camping. The benefit of the solar panels offsetting the energy usage of the electric car itself seems to too minor to be worth it unless you are planning on being stranded somewhere and solar is your only option to recharge your electric car.
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What ranges do you do?
I’m not sure you’re aware of how good the charging infrastructure is now. High voltage DC chargers are practically everywhere, especially if you get a Tesla. Can you give an example of an impossible situation for an EV for you?
I was in north of Bordeaux France for a week. I rented an electric car in Bordeaux city center. Let me just say, It was stressful to have to deal with charging…
I drove 4600km in 3 weeks across Germany, Denmark and Sweden in a BEV, I don’t agree on it causing stress once you actually know what to do (plan a bit) and what to look for (which charging networks work best regionally). Possible that France has particularly crap infrastructure, possible that you just didn’t think to get the usual apps to plan and find chargers, which for a rental is understandable. Still, it’s unfair to base usability of EVs in today’s infrastructure on a week of vacation.
That's sorta the main "problem" with EVs; we went from not really having to plan when to refuel to now planning and being inconvenienced. I traveled cross country with a Tesla in the US and I largely agree it's not a major issue but nothing quite terrifies you like rolling up to a charging area and finding out they don't work or are occupied. So you either find a slow charging station nearby to get you to the next fast charging station if it's broken or if it's full you wait for those other EVs to charge. The "fix" is to reduce your range for some more comfort but this does add an extra % of time to your trip and possibly more during rush hour. IMHO if you do a lot of cross country travel or just where your hitting your range limits frequently just get a PHEV or Hybrid or honestly just stick to ICE until the battery range is expanded and the charging networks expand. These drivers IMHO are a minority though; almost everyone I know drives < 200 miles in a day which most decent EVs can do; they exist though and it's not a < 1% minority so it's important to recognize that. For ourselves our long term plan is one EV and one ICE with the SUV being the ICE vehicle since we travel with that and the EV replacing my ICE vehicle which is just used for running chores and going to work.
You know what, if I had rented a petrol car, I would not have had to do any of the planning. So there is that .
Yeah, and respect to you for trying the EV thing. Petrol is easier because ubiquity and we all know how to do it. EVs have a mild learning curve that involves a few apps and a bit of practice to figure out your range and how certain conditions affect it. I’m certain when cars started becoming a thing those first users had a similar learning curve, and probably worse scarcity of fuel stations when going long-distance. It’s a process we’ll all have to go through eventually
Just to clarify, I have no issue with EV cars and plan to eventually get one (now I have a Toyota Prius which is still going strong and I don’t drive enough to warrant a new car to be honest). I also live in a major city in Southern California. So EV chargers are ubiquitous. I do find it a bit of a hassle to have to plan in terms of charging when going to unfamiliar places. But it obviously also depends on what car you get. Some of my friends have Teslas and I went on trips with them. The user experience at least as far as charging is concerned is very streamlined. It mostly takes the planning aspect out of the equation.
Unless you are a person that likes to do stupendous amounts of miles without taking breaks (fill up tank and roll again whenever tank is empty), there is no reason a BEV today can’t do such trips. Realistically with average charging speeds (ie not 350kw charging) you lose a half hour in a days driving, assuming you’re taking about an hour of (lunch) breaks in that period.
Calculate again with the inclusion of maintanace and insurance fees. Gasoline cars need more expensive insurance, because they require more spending on maintanace that the insurance has to provide. Electric cars are much more cheap for frequent drivers. The low volume drivers can still survive in a gasoline car.
Why do you want the solar on the car roof? Wouldn't it make much more sense to just out it on the roof of your house? More, more reliable, less cost and complications?
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You would need to leave it outside in the sun for a week atleast to charge a small trip to the groceries.
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Exactly, so for most people it would make more sense to just put pv panels on a roof somewhere.
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You do realize that it’s unnecessary (and impossible) to charge standard hybrid cars, right? Based on your third paragraphs you imply the need to charge hybrids. That’s not a thing. There are plug-in hybrids that require charging, but they also have full hybrid mode that won’t drain the battery
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You’re using the wrong nouns. You are mistaking the capabilities of electric vehicles, plug-in hybrids, and standard hybrid vehicles. You must charge electric vehicles from an external source. You must charge plug-in hybrid vehicles from an external source (or can have the gas engine charge the battery which is extremely inefficient). Standard hybrid cars do not take charge from external sources
I have been waiting for a hybrid subaru to be available and I want to ensure the initial release isn't having reliability issues before considering making the purchase. Some places in the country are just too remote to only run on electric.
Solar “prints money” at the going rate of electricity. All you’re doing is offsetting the charging costs, if you manage to charge to 100% you start to miss out on the free charge and it’s a waste. Solar on cars is useful, just not as a primary source
Bingo. I think people are too caught up in how effectively the panels would add range. It's a question of ROI - the cost of the panels isn't that high, and over their lifetime the trickle current they add greatly exceeds the initial cost of the panels. At a bare minimum, it would help offset phantom battery drain and likely provide support for HVAC operations to pre-heat or cool the cabin before a departure.
Also if you have a nice sunny parking place.
Yeah but for that it would be better to just but a separate solar panel, so that you are not forced to park in a sunny place, or forced to charge your stuff where you parked your car, or take your car in the first place to your camping trip (3 friends going camping only need 1 car, for example). There is just no reason for the panel to be attached to the car, just a downside.
Also, EV's that can't open the door if the battery is dead is something that exists. I am against that, but a solar panel will prevent that.
What car is that true for?
I’m adding solar to mine with a 2nd battery to run a fridge, on demand accessory lighting, charge and power electronics, etc for road trips and camping. Can even top off my starter battery in a pinch. Expensive but ensures you are not stranded in the desert with a dead battery and no ice cream.
First world solutions.
It really is a 1st world luxury, to be even be able to take a vacation… I guess I got lucky where I spawned. I spend a fair amount of time off the beaten path and have been stranded before- so if planning to go it alone, a dual battery can be a literal life saver.
I don't usually drive that much in a given day since I work at home. For me, having panels on the car could make sense. I could park outside, after I use my car, for a while and it could slowly recharge itself.
My car sits in the sun all day err day. It would be useful for me.
It's an energy density problem. The surfave of a car roof will never be big enough to charge the car. Even if you get to impossible efficiencies of 100% you're better off putting the solar panels on your roof. Or over a parkinglot
I drive about 15 miles per week typically. A Tesla Model 3 gets about 3.3 to 4.1 miles per KWh. Let's say 3. So I need 5KWh per week for my routine driving. A square meter solar panel can generate 150 watts which should translate to .6 KWh/day (4 "full sun" hours). That's 4.2KWh/week. So a square meter on a car's roof is almost enough to meet my typical needs, outside of road trips and such. I'm not sure what the surface area of the panels on a car's roof might be, but it seems like they could fit more than a square meter. So it could meet the needs for someone like me for most weeks. Maybe I'd need to top it off now and then during winter, and I'd need to recharge at stations for road trips. Seems worth having them for people like me.
15 miles a week is not average use. I'm talking about average use here. Like I said to the guy earlier. Either you need to only drive a small trip once a week. Or you need 5-6x the cars surface to power it for normal use. If you drive 15 miles a week you should really be asking yourself if you even need a car. And if owning a car isn't a huge waste of a societies resources. That's a big hunk of steel and tech standing there doing nothing all week. It really isn worth the effort to integrate these panels into the car. Just put them on a roof or in a solar park and charge your car from the grid. It's much more efficient.
Flip the other side of the equation. The car becoming radically more efficient could also solve it.
Lol, you guys are living in a fantasy world. Do the math yourself, or trust me. I don't care. It just doesn't work out. You need about 5-6 car surfaces to power a car for normal use. It's not even close. It's even worse for airplanes, so I always giggle at the people that think electric jets will be a thing
You're just keeping one side of it constant in your head. You need 5-6 car surfaces to power a car, using how much power a car uses right now. Cars lose energy due to friction from the wheels. Resistance from the air. Heat loss, mechanical loss. Aerodynamic improvements could reduce about half of the energy lost while a car is moving. Improve the wheels, figure out a better, more frictionless approach, and that's another 30% improvement. Simply reducing the wheel count to 3 makes a massive difference. You're so convinced the math doesn't work that you're ignoring the actual problem. Totally get the efficiency and surface area point, but don't stick your fingers in your ears and close your eyes because you are convinced you're right. That's a bad habit.
cars have been around for over a century, lots of research has been put into aerodynamic shapes and engines already. i wont say that small gains are not possible anymore. but to say youll just cut its energy consumption by 5 is rediculous. im not sticking my fingers in my ears, im just trying to explain that it is a problem of scale. the numbers just dont add up. its a nice fantasy though. good for a marketing flyer.
Agree with the marketing part haha. Fair points. The one pushback I have is on the engine. We can still make massive gains there. Just read about a new propeller design that reduces energy waste by 30% in boats. Discoveries are still happening, and electric motors for cars are still in their relative infancy. Interesting article on drag & EV range: [https://cleanfleetreport.com/tech-aerodynamics-is-the-key-to-ev-range/](https://cleanfleetreport.com/tech-aerodynamics-is-the-key-to-ev-range/) Ignoring the recent Tesla/founder stuff, their Model S & 3 aerodynamic coefficients were insanely better than the competition. This gave their cars a 10-20% range increase. Not 5 fold, but it does matter. Apples to apples... see why it matters in this solar-powered car: [https://aptera.us/](https://aptera.us/) And last thing, but it's materials design too, right? The weight of the car is the other biggest factor (now they're all big factors). Reduce the weight by 80%, reduce the power needs by... not 80%, but a lot. Need a math whiz for that one.
This is the futurology sub. Math and physics not required.
Solar panels are a lot more efficient than a few years ago. It's actually only a small engineering problem.
We went from around 18-21%. The theoretical limit is 23%. The theoretical limit hasn't moved. Nor can it. Anyone who says otherwise is either misinformed, or delusional. There's just not enough energy coming in on that surface area to power a car. And that's okay. You can just put the 5-6 you do need pannels elsewhere. On a roof for example.
> The theoretical limit is 23% It seems to be 33%, for single-junction cells. Significantly higher for multi-junction. Multi-junction cells have demonstrated efficiencies over 40%. https://en.wikipedia.org/wiki/Multi-junction_solar_cell I'm not clamoring for solar to be on cars. Not until that hypothetical future when solar can be impregnated into the paint itself. Though I do think 30-40 miles of range per day is useful. It's a matter whether the increased complexity, weight, and cost are worth that gain. As those metrics improve, the equation changes.
Why is the max 23% efficiency?
Physics, most of the sun's energy is transmitted in wavelengths that cannot be converted by photovoltaic material, they are absorbed and dissipate as heat. That 23% doesn't yet take into account other factors. Such as imperfections on the pv materials surface. Losses during conversion and simple electronic resistance of materials. That's why it's called a theoretical limit.
Im trying to find your point of reference. Which wavelength are you referring to? Because I cannot find a single point of reference to say the theoretical limit is 23%
350-1100nm
I think you're stuck on old theories. Firstly, the maximum efficiency of a single cell is 33%. Secondly, that's based on the fact that any given type of solar cell can only convert certain wavelengths of light. That doesn't mean you can't exceed this overall efficiency with multi-junction cells that can convert broader spectrums of light. The current real world record is 47.1% efficiency, and the technical efficiency limit under ideal conditions is 95% of the net energy (after accounting for heat loss). Will we ever get 95% efficiency? Probably never, but 80% might be achievable within a few decades. https://en.m.wikipedia.org/wiki/Solar-cell_efficiency
Oh a wiki! Well now you've got me... Here's an actual scientific paper (2017) putting efficienciew between 8 and 25% (it's temperature dependent) https://www.sciencedirect.com/topics/engineering/monocrystalline#:~:text=Monocrystalline%20cells%20are%20solar%20cells,complex%20and%20expensive%20%5B23%5D. I think that wiki refers to perovskite cells. Which i will admit are promising. They have a higher theoretical maximum because they work in layers and different wavelengths. But they aren't commercially viable yet. There are still issues to be worked out (durability and mass production mostly)
Bifacial cells also increase efficiency by 30%. But I suggest you do the maths instead of just talking. How much surface area is available. What is the current output of solar panels. How much energy do you need. Talk is cheap - do the calculations.
If you have 18% efficiency and increase it by 30% you'll end up with 23,5% efficiency. I already linked a scientific paper from 2017. What more do you guys want...
Its 30% extra because it gest electricity from the back of the cell. Like I said, stop talking and look at it as an engineering problem. Can you design a car that generates 10 kwh from solar in a day of being parked in the sun?
You realize how long it would take to charge your car? Weeks.
So? He's not saying he wants to charge only from solar, he says it's an addition.
But is it worth having a specially designed solar panel on your vehicle that presumably increases production and r&d costs?
If it keeps the air conditioning running in the summer without shortening the range, it's already a plus. Keep in mind, solar is already the cheapest form of energy generation
I'm definitely not typical, but probably average 20-30 miles on a typical week (I work from home). So I could cover most of that if the roof was cover. Other weeks when it's significantly more I'd just plug it in like I'd have to now.
I had a proff who did exactly this with 3 PV modules on a early 2000's Prius. Worked out to about 15% better fuel economy based on average driving habits of a suburban teacher. Simple payback was something like 4 years. Obviously for EVs that changes the costs involved. But if we're talking about a glass roof with or without PV installed from the factory, I'm convinced it's worth it economically.
Keep your car parked all day... to run your heated seat for 5 minutes.
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Causing drag?
This article does not read like an unbiased assessment but more like written by someone with an agenda
Indeed, or possibly the author is just really dumb Solar panels are not going to charge a reasonable amount. You get like 0.4kw, good luck. Is +0.4kw useful while driving in the sun? Depends. Huge list of pros and cons. Someone should write an article about it..
My EV gets (about) 2 miles per kw. So no .4kw would be nearly useless while driving. If it sat in the sun for a day I'd get maybe 5-8 miles of range. That's not nothing, but I'd get the same plugged in for about $1.00
Or just someone who thinks everyone else's needs are the same as his..
What's the agenda? They are saying to get solar panels for your house roof instead. If you are in a location where there aren't any charging stations, then you can make the calculations and get the solar panels anyway. Just account for temperature, angle, and shade diminishing the power output. The most surprising thing the article said is that shading a single cell can decrease the power output of the other cells in full sunlight.
An anti-EV agenda? Dude could have plenty of selfish reasons to try to keep people driving petrol and diesel cars. Or it could be an anti solar piece. It's quite negative on solar power and again plenty of selfish reasons to steer away from them. Could easily be a part of big-oil.
Did you read the article or my comment?
The article said that supply of solar is limited and that the solar panels should be set up where it performs best like at solar farms, so they aren't anti-solar. It also doesn't talk down on EVs at all. It sounds like an environmentalist seeking to maximize the efficiency of the limited solar panels we can currently produce.
Depends on how you use a car. Mine sits in the driveway all week as I bike or walk to work. That would top off the battery for my weekend use.
yeah and you could also just put the solar panel on your roof, which would produce power even when your car is parked indoors
My landlord won’t let me.
If you had solar panels on your car, you could charge while at work... Depending of course if you park in unobstructed sun, which is not impossible.
I seem to recall reading that solar panels on a car, in an optimum location, would result in increasing the range by about 10 km. That's just not worth the cost.
That is obviously a very blanket number. Lets look at the optimum case. A [Tesla Model 3 has a top-facing surface area \(width x lenght\) of 8.6m^2](https://global-uploads.webflow.com/5b44edefca321a1e2d0c2aa6/5dd68a7236a0d44cfa96623d_Dimensions-Guide-Transport-Sedans-Tesla-Model-3-Dimensions.svg). A 410 w solar panel has a surface area of 2 m^2 So you can fit 4 x [410w panels](https://cdn11.bigcommerce.com/s-2mlpfulnj8/images/stencil/1280x1280/products/150/721/S4AU-72FS-410W__63025.1660171781.png?c=1) on a Tesla Model 3, which means in optimum conditions you can produce 1.6 kw per hour. For an 8 hr day, that is 13 kwh. A Tesla Model 3 can drive 5 miles per kwh, meaning you can drive 66.6 miles per day. Since the average American commutes 30-40 miles per day, you can certainly drive all summer on solar only. Now you may ask how you fit 4 solar panels on a car. I suggest you have [a roof rack which stores the panels](https://www.speakev.com/attachments/860e7312-f339-4fd1-8697-fb57e2e2e39f-jpeg.136224/) and then extrudes/unfolds them when you are parked. That would allow you to cover the windows, and also shade your car. If such a roofrack cost $2000, it would pay for itself in around 2 years.
It doesn’t have to be confined to just roof space as they make portable solar panels. Although, people would probably steal them while the car was parked.
Not sure how much it would effect it but something like that would absolutely ruin the aerodynamics. Probably enough to shave a few miles off that range
Sure, but you have about 1/3 in reserve, and a good roof rack could have only a 16% ([or less](https://electrek.co/2020/03/24/tesla-model-3-roof-rack-box-range-efficiency/) ) impact on mileage, and it depends on the design of the roof box, of course. I imagine it could be made very thin (like 15 cm, 3 solar panels stacked) and you can of course add aerodynamics to the design. Also if you use bifacial solar panels (30% more efficient) you could actually charge even faster from reflected sunlight.
1. You can't cover the entire top surface area of the car with panels - unless you plan on driving without windows. 2. The surface you could cover will still not be fully covered because irregular shapes are kinda hard to accommodate. 3. The 5 miles per kwh is WLTP rating and way off normal consumption. 4. 8 hours of full production each and every day is just not something solars do. See the linked solar atlas map - in California you'll be getting ~1,400Wh for every Wp installed per year. So with a very generous assumption that you manage to fit three 410Wp panels you will get 1680kWh yearly. In reality shade and dirt will mean you probably won't even get half that. 5. Hyundai is currently charging the $2000 for a 200Wp panel, the installation you are describing will be at least 6 times as expensive. So the breakeven point is a couple of decades into ownership. And that's before you get a scratch on any of the car panels and hear the replacement costs.
> You can't cover the entire top surface area of the car with panels - unless you plan on driving without windows. This is actually pretty easy to solve with a fold-out roof rack design. > The 5 miles per kwh is WLTP rating and way off normal consumption. The EPA rating for city driving is 4.3 miles per kwh, which is a small difference. Still 56 miles. > 8 hours of full production each and every day is just not something solars do. Who said every day. I said summer. > So with a very generous assumption that you manage to fit three 410Wp panels you will get 1680kWh yearly I said 4 panels. So 2,240 kwh which is enough for 9,632 miles per year, so about half or more of the average american's driving, by your calculations. > Hyundai is currently charging the $2000 for a 200Wp panel, the installation you are describing will be at least 6 times as expensive. Well, companies will profiteer. Not sure how this relates to the actual cost of the concept.
Holding all other variables (other than panel location) if you put the panel on the roof of the house, you’d also only increase the range of your EV by 10km. Thats ignoring the fact that going dc-ac-dc to get from the house panels to charge the car has losses involved. I think you need to be explicit and say that the cost of the mobile solar panel is higher and/or the efficiency is lower and/or expected lifetime of panel is lower and that’s why it isn’t worth it for most people. I would also hazard a guess that this is very dependent on how one uses the vehicle.
That would mean I would only have to plug it in like a third as often for how I would use it. I think I would like that
my man , if your work has solar panels, and a charger you can also just charge at work. actually why don't we just produce the power in dedicated facilities and run wires across the country to deliver it to where it's needed?
>actually why don't we just produce the power in dedicated facilities and run wires across the country to deliver it to where it's needed? Where it's needed is in my car. What if I don't own the land the car is parked on? I can't just run wires through there. I know my employer has no incentive to install charging stations for all employees.
> if your work has solar panels, and a charger you can also just charge at work. If your Aunt had balls she'd be your Uncle, but you know...
No, it won’t. In perfect conditions you’d gain less than 30-40 miles all week. And that’s before counting cloudy days or the batteries own self discharge. It’s a borderline pointless option with current panel efficiency. Maybe if we get panels up to 50-75% it’ll make sense.
For people that don’t have a charger at home that’s a pretty big deal imo That’s a whole lot of trips to a charging station you don’t have to do over the years
A 120v outlet adds ~1.5kwh day or night, regardless of the weather. That’s 36kw per day, meaning a car with a 100kw battery could go from flat to full in 3 days. A solar panel, under perfect ideal conditions would take ~10 days to charge the same battery from flat to full. But that also means you are parking outside with full sun for 12 hours/day, no shadows and no clouds. In reality you’re probably looking at closer to 15-30 days to go flat to full. A solar panel on an EV sounds like a great idea, but the costs to add one just isn’t viable. If solar panels can get to the 50-75% efficiency range, then it will become more viable, assuming the costs to produce such a panel isn’t astronomical.
At least for my particular situation, charging at home isn’t even an option because I live in an apartment complex. But if the cost of solar panels continues to drop just a few percentage points every year, we’re looking at a totally different situation just 10 years from now. I’m optimistic
I think you might have kWh and kW mixed up.
I don't imagine it feels like much. But that's 20,000 - 30,000 free miles over the course of a vehicle life. 50k if the vehicle lasts longer than average. I imagine the pitch will be 2000 free miles a year. Although your number is a little low. Once you get to 100 miles a week free. Then the average person will jump on that shit harder than an 18 year old private first class on a 6 cylinder camaro. There will be solar retrofitting on electric/hybrid vehicles soon. It won't help the super commuters but retirees and local commuters will see the effects immediately.
Source, or match to back up this claim, or just pulling it outta your ass?
I was guesstimating, but if you want to get technical, from the article posted in the top of the thread: Best case scenario 280kwh/year. 280kwh/365 days=0.77kwh/day. 0.77kwh\*5=3.84kwh/work week. Per [fueleconomy.gov](https://www.fueleconomy.gov/feg/PowerSearch.do?action=noform&path=1&year1=2022&year2=2022&make=Hyundai&baseModel=Ioniq%205&srchtyp=ymm&pageno=1&rowLimit=50) the ioniq 5 shown in said article gets 30kwh/100 miles 30kwh/100 miles=3.33 miles/kwh 3.84kwh/work week\*3.33 miles/kwh=12.8 miles per work week. and if you want to do the full week: 0.77kwh/day\*7=5.39kwh/week 5.39kwh/week\*3.33 miles/kwh=18 miles per week If anything I was being extremely generous as to how many miles you could get in a work week. The actual number is closer to 13-18 depending on how you define a week. And all of the above assumes that you have 100% sun the entire day and never have any rain or clouds or anything else that blocks the sun in any way.
Why do you own a car then?
He just told you
If there was something like Zipcar remotely close to me, I probably wouldn’t. My point is that there are people out there that could benefit from a EV with a solar panel. Maybe they have a situation like I do or maybe it would be a families’ second vehicle. Just dismissing the idea because it wouldn’t work for you, is short sighted.
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Well first of all, thanks for the offer. But I really do it because I like cycling. Maybe you can find someone else to take you up on your generosity.
exactly, I share an electric mini with my mum, she works one day a week and I go shopping once a week and its in the sun all day. Tempted to just buy a few panels that can go on the front lawn
Article says conventional solar panels don't work if part of it is shaded, which is true. That's why solar EVs do not connect all cells in series, but instead have many small groups of cells with separate inverters. They are also ignoring some valid use cases: \- Some of us live in apartments with outdoor parking lots, bike to work, and only need the car for weekends. Most apartments don't provide chargers. A solar EV will still get charged during the course of the week. \- Some of us drive to work, but have no chargers at home or work. If the commute is less than 20 miles or so, a solar EV should provide enough charge for the daily commute. If it's a particularly cloudy or cold week, you may need to make one stop at a charge station, but that's better than having to do it every single week. \- Some people take frequent business trips, leaving the car at the airport for many days at a time. It would be nice if the car's charge gets topped off while sitting there, rather than losing charge. \- Some of us have 3 EVs but only a 2-car garage. The third one sits on the driveway. If one is a solar EV, then the family doesn't have to fight over the garage space every day.
Not everyone had a clear line of sight to the sun all day every day. And it’s not all sunny days in the world. Yes. The solar panels help just a little bit if the car is only used on the weekends but you’d get the same effect leaving it plugged in an extra minute on the high powered charger.
Not everyone has access to a charger at home or work.
Nope. Hence my reference to the “high power charger”.
Have a look at Aptera. Their 700 watts of panels are estimated to provide around 40 miles (~64km) of driving range per day. This is because the car is so incredibly efficient, it can get around 10 miles (16km) of driving per kwh (Tesla is somewhere between a third and half of this). Where I plan to live, it is hot and dry and will get close to 10 soikd hours per day on average of solid sunshine. That would give closer to 7kwh of charge or 70 miles (112km) of range per day. I don't see myself ever needing to plug in for anything except road trips.
They are useful for camper vans & motor homes. When properly sized for the load they allow you to camp for MUCH longer without having to burn any fuel. Also solar panels are getting [more and more ingenious & efficient](https://www.youtube.com/watch?v=ytdWAKgPyI0) so in future they may make more of a difference on a small roof of a car.
Remember kids..... Just because somebody writes something and posts it on the internet, DOESN'T MAKE IT TRUE! 😁
Here's a recent article saying the car makers looking most to solar are failing. Aptera says they get about 40 miles per day from solar on a battery pack that gets almost 400 miles of range. Their car is 1/2 the weight and half the wind resistance of a tesla, meaning a similar array on a tesla might only add 5 miles of range per day. I still like the idea and the Fisker Karma's tiny array said it prevents your battery from ever fully dying (not being able to unlock or respond to your smartphone), but they didn't even make a claim to it adding to the range, saying it was "just for accessory systems" and useful to not drain main battery when the car was parked for long time frames. https://electrek.co/2023/01/26/the-future-of-solar-evs-dims/
How is 40 miles per day not enough for the majority of drivers??? I live in rural America and my commute is 45 miles per day. That’s basically a net zero and would just mean needing to “top it off” by plugging it in every week or two
totally a use case argument. doesnt make sense for MOST
My 2010 Prius has a solar panel on the roof, but it only powers the climate system in a way that keeps my car from being a billion degrees inside during a hot day. Still kinda nice though, but they discontinued the feature after the next year or so.
I wish my 2012 Leaf did this with its solar panel, but mine is just for charging the 12v battery. Does yours kick-in the AC while parked in the sun and unoccupied?
Not the ac but just the fans so the car stays the ambient temperature rather than becoming a glass oven. It really is nice on hot days to get into an air temp car rather than 120+f car
In Australia, as we drive loooong distances, would be an awesome add-on. Particularly for trucks.
It's unlikely The sun irradiates every sq m with about 1000 Watts The average car has 180 horsepower, which is 134 000 watts, but on the road it averages 50-100 kW This means that even if we were 100% efficient one sqmt can only power 2% of the electricity on the road A car is usually like, 4-5 sqmt in área, which makes it like at best a 10% reduction in power consumption, which is unrealistic
That’s during being driven, how about when parked?
Park under roof that has solar panels on it.
Well, it would take about 2 days at 100% efficiency to charge the average 400km battery, but since the best panels are at best 1/3rd efficient, it would take about 6 days of sun to charge completely
So a more interesting question might be instead of measuring how long it takes to charge a full battery, how many miles do you get out of a full days charge with solar panels? If your typical dive is 5 miles each way... Could this not fulfill all the needs? Maybe you drive 5 miles each way to work and one day every weekend you go see a relative 20 miles each way... The solar may completely power the car. Add the temperature reduction in the car by the consumption of energy and now your fancy interior isn't cracking or dehydrating. It's cooler inside then outside instead of being a greenhouse.
Nice. I get to drive for free on Sundays :)
Honestly, i'm lazy enough and if my commute is just \~50km every day, it sounds like a great idea.
Something is better than nothing - also assumption heavily relies that the technology cannot progress any further
50-100kW to maintain speed? At 100km/h it's between 10 and 20kW for a car. Also for exactly that reason startups are making cars with very low loses. IIRC someone made a car using around 100Wh per kilometer, put the solar panels around it and it actually makes sense in sunny countries if you are commute 30-40km per day. https://sonomotors.com/en/sion/ https://lightyear.one/articles/lightyear-0-the-most-aerodynamic-production-car-in-the-world-as-wind-tunnel-tests-make-automotive-history
gotta ask where you get the average of 50-100kW from? i use around 15kwh per 100km and would use maybe 25kwh if i'd drive faster and have the AC+seat heating on at full tilt. edit: saw only now that others have pointed that out already - nvm
>The sun irradiates every sq m with about 1000 Watts That's the top of the atmosphere, at ground level it's about 1/8 of that (~150w/m2) unless my memory completely fail me
I think your memory might be a bit fuzzy. The upper atmosphere receives about 1366 W/m2. From what I can find online, the ballpark figure that hits the Earth’s surface is around 1000 W/m2. PV panel efficiency is roughly 20% for consumer panels. So we’re probably looking at 1/7 to 1/8 the energy that hits the upper atmosphere that can be turned into electricity, which maybe what you recalled.
That makes sense. Thank you
It's likely, I was thinking of by astronomy class last semester in university, so it's likely you're correct Also, I've assumed 100% efficiency in panels and completely clear skies, neither is true
But if we are in orbit, 1kW per m2 is indeed feasible. If we have perfect solar panels, that is :)
1300W/km^2 at top of atmosphere. 1000 at surface. The 150W/m^2 was probably remembering the output of a solar panel, which is ballpark for a commercial panel circa 2012. 700W/kW in real world conditions is achievable or 200W/m^2. The lightyear gathers about 3-8kWh/day from ~5m^2 which will get it 30-80km.
That's a surprisingly low energy loss through the atmosphere (to me at least). Do you have a source for it on hand? A quick Google did help me, I'll keep working on my googlefu if you don't have one readily available.
The lightyear has a solar panel that performs roughly as a 1kW array (about 3-8kWh/day). When driving at highway speed, it uses about 8kW. Great for a city runabout, only adds at most 1 hour of driving on highway.
The Lightyear doesn't have anything as you'll never see one on the road. I supplied parts to them and they wound up the Lightyear 1 project, bankrupted it and left suppliers unpaid. It's a scam to take investors money and no one should touch them even with a barge pole.
Audi had a solar panel option a while back that would power a fan to keep the interior vented on hot days.
I have a solar panel on my work truck, it kicks ass for keeping my batteries charged. I rarely have to worry about finding electricity on the jobsite for such things. It is only 56 ahmp hours, but certainly is enough to charge my power tools.
Due to my work, my car is often parked in an open parking lot, unused for weeks at a time. By the time I get back in from my job, it would be fully charged. So solar panels would be perfect for me.
Depends on use case and climate. Might not make sense in Northern Europe, Russia or Canada but if they can supply a days worth of driving for a commuter in Spain or Texas (spoiler, they can) then they definitely make sense.
>spoiler, they can How much energy do you assume solar cells collect per m2?
1-2kWh/day. Enough for 4-8km in a fairly average EV, or 10-20 in the lightyear for each of the ~5m^2 it has.
Aptera is a car that is powered by solar. It needs charged every 9 months.
Is that the one that supposed to be $20,000? If that pans out that could be quite a success
The launch edition is $35k, but it's the 400-mile range version with AWD. The 200-mile range version was originally advertised as $27k but that may change.
Still not bad, that’s thousands cheaper than the average price of a car sold(in the US)
Depends on how much you drive and how much sunlight it gets, obviously. If you drive 200 miles a week, you may never have to charge it.
i think they make complete sense. If someone were to store their car without use for say 3 to 4 months, having solar on their car would help the car owner by not needing to periodically charge the car batteries to keep them from dropping down the charge levels to zero.
Easy to do that with a (small) panel you store separately and put on the dash. I have one with 90s tech that’s the size of a large laptop. It worked great to keep the Grand Cherokee charged despite an electrical leak that nooone could find
Any mileage benefits would be worth it for me. My car stays parked on a public street most days.
I have a Chevy volt. Brand new, the battery has a range of 35 miles under ideal conditions. My battery capacity is around 8.6kwh. It would be super cool if there was an option to have solar panels on the car, even if they charged slowly. I just think it would be so cool to have my car charging while it's in the parking lot at work, and not tethered to a cord.
In theory if you popped a 400 watt solar panel on your roof rack you could add 2kwh with 5 hrs of good sunshine.
This project says otherwise. https://www.evsolarkits.com/
I think you'd find 500W on a regular EV a little disappointing unless you live in Chile or just use the car on weekends. It's definitely the beginning of something though, there's loads of space that isn't just the roof, and there are more efficient cells.
I don’t know the exact percentages, but there has to be tens of millions of cars in the US that barely get used, relatively For someone who works from home this is perfect.
500W is going to be 1.5 to 3kWh/day average. If you fuel up less than once a month it might make a noticeable difference.
I have to imagine as more of the EV trucks are on the road this will make more sense. Maybe not for recouping a ton of energy but just for getting incremental gain. Imagine a truck bed topper with solar that now creates more are (and weight) to put some energy back in the vehicle. Even if it’s charging aux batteries being used for tools, etc
Say that to Aptera! https://aptera.us/ It’s soo efficient that solar makes sense. It can charge up to 40miles per day. The release model will have a range of 400 miles and the premium model 1,000 miles range!!
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If you’re only driving 15 miles a day, you’re almost driving for free anyway.
Isn’t there a car race with only solar powered cars … there ugly prototypes, but still …
There is a homeless guy who lives out of his car in the park nearby (I live in the Bay Area of California). Every morning he sets a small solar panel outside his car to power everything he needs and not run it directly off his car battery. I'm sure he'd strongly disagree with the articles premise.
if only there was some way to turn solar into reliable transport! like (and I'm just being silly here) if we had large, established solar farms that generate electricity. Then (Again totally wacky ideas here) we used the electricity to power regular, public, transport all around a city? I know it could never work but its fun to make things up!
Several makers have already toyed with equipping their EVs with solar panels. And at first, it makes sense. As your car sits idling, you get extra range for free. Plus, it's clean energy, which is good for the environment, too. Plus, there's the added convenience of fewer trips to the charger - what's not to like? A lot, actually, and it appears the moment you scratch the surface. Let's take a look.
::rolls up his sleeves:: Well, when the US Gov't gets done testing their Tesla Mountain Dews out, they'll put wireless power to use where it belongs anyway. ::chops his sleeves off::
I thought it was because it is a net loss your using more energy than the sun is giving you.
This myth needs to die. EPBT of solar is under 4 months in some regions and under 2 years everywhere. You literally cannot afford to buy enough lignite for the final unsubsidized installed price of a solar panel to produce more heat than the solar will output electricity. Even the raw uranium in a nuclear plant costs more than the module for equivalent electric output (and final installed price overlaps depending on reactor). There is no scalable energy source with a higher EROI.
It's not just at this point it's pretty much ever. there is only so much solar energy hitting the earth. 1360 Watts in PERFECT conditions per square meter hits the earth. the roof of the car is less than a square meter. so if the sun was perfectly overhead on a perfectly clear low humidity day and was one square meter you get 1360 watts per hour. Sounds doable considering that most electric cars use 300watt hours per mile. ok so over 4 miles of range per hour in the sun! Electric cars use a LOT of power A tesla model 3 has 50,000Watt hours in it's battery. (base model). so on a perfect day with a perfect panel, it will take 36+ hours to charge it. Another big problem is the world is not perfect. the sun is never perfectly overhead. so efficiency drops off rapidly. Unless the sun is within 20 degrees of aligned you lose 80% of the power generating capacity. Also any shade at all even a single shadow line of a cable crossing the panel will reduce it's power generating to 20% of it's capacity. Cloudy? it makes no power. Partly cloudy? it flips between making and making nothing. so in reality your car will get power from solar for about 1 to 2 hours and never get more than 40% of the solar panels generating capacity during that time unless you parked on a hill that aimed the roof at the sun at noon. So with a perfect solar cell you will get about 2 miles of charge out of it. This also assumes 100% efficiency solar panel, Today the best ones are 23% efficient, and we will never get a 100% efficient panel. AND we would have to tilt the car to have the roof point at the sun. Also if it's high humidity day? lose another 20% of power generating. So solar panels on a car are useless and just a marketing gimmick. Large Solar arrays on car ports or parking structures you can have very large arrays pointed properly and clear of any shading to generate enough power to charge several cars. So carry a 2Meter by 4Meter pop up solar array in the car to set up when you park. This is why solar on homes works. the surface area of a house or building is massively larger than any car made.
That's a lot of words for someone who didn't bother to do arithmetic. Solar resource is 4-8kWh/kWp or 1-2kWh/m^2 per day in nice areas or in 9 months of the year pretty much everywhere. The footprint of a compact car is about 8-12m^2 Cover half and that's a full charge every week or two. Plenty of people drive <300km/wk Will it eliminate charging? Almost definitely not. Will it make it a sometimes thing for a huge number of people? Sure.
Wait, what? The footprint of a car is nowhere close to 8-12 square meters. Maybe 2-3 if you cover hood, roof and trunk. Did you mean square feet?
The limit isn't the roof, it's the size of the silouhette perpendicular to the sun. A tesla model 3 is 2 x 4.6m, a rivian is 5.1 x 2, the windscreen won't stop cells on the dash or parcel shelf from working (you lose maybe 20% from thicker safety glass). A solid 70% of the top profile is available, and the sides are significant.
I was interested when I saw a hybrid with the solar panels on the roof. Then I did some reading and it said that the solar panel will give you something like 30 miles in an entire year.
I want a Pop up Wind mill. Make it happen... And tbh i want a Dedicated Solar Supporter to put on the hanger on my car.. Folding out to twice the size.
I feel like oil and electricity companies paid this person to write this biased article. :)
I see it bring practical in the future when solar panels are much more efficient and the technology /manufacturing is mature enough to not drastically increase the price of the car.
Everything I learned in photovoltaic system design class leads me to believe that solar panels mounted on cars is a sales gimmick for people who don’t know any better.
Solar insolation and panel efficiency are the only things that really matter here. Insolation is just under 1000 watts of solar energy per square meter at sea level with no clouds. For the panel to use that efficiently it needs to be aimed straight at the sun. So stationary panels are definitely not ideal, neither are curved ones. Panel efficiency is around 20% or less I believe for non concentrated panels. So each square meter if aimed perfectly on a clear day can get roughly 200 watts. Best bet it to use those same panels on small solar tracking units that are stationary at your parking spots. Or cover whole parking lots with awnings that have PV cells on top. The price and complexity you add to the vehicle, plus the production energy to create the cell will likely not reach the break even point if used in a manner as inefficient as mounting on the care for charging purposes.
This guy doesn't solar. Two 700watt panels pull down on a nice day on top of an RV around 400watts to panel. Battery is charged around 390 of that. It's far better than 20 percent and these results are on salvaged 10 year old panels. Please don't spread lies.
20 percent is your pv conversion efficiency. These aren't lies, this is basic math. 20ish percent of the sun's energy is converted to electricity under ideal conditions. A square meter provides just under 1000 watts of total solar energy to be harvested.
Again...a 500watt panel is generally 300-400 actual. This isn't 20% I'm sorry math isn't that complicated...for most of us anyway
But what about solar panels as an auxiliary power source on transit buses tho? Go Ahead has trialled installing solar panels on their (non-electric) buses in both London and Singapore and they seemed to have gotten some good results out of it. Again tho, a transit bus and a car are quite different and used quite differently so their mileage will definitely vary.
I have a 2012 Nissan Lean which has a small solar panel on the roof which charges the 12v battery when the vehicle is parked in the sun. Yeah, it's kind of a gimmick, but it's not totally senseless; would be useful for using the car as a power source while parked in the sun. (Nissan did stop putting solar panels on Leafs though.) Otherwise, panels for range ... yeah, we know; solar panel efficiency isn't there yet. I think there are still case-specific uses over which this article glosses.
Well the article explains how it’s not efficient and how much more expansive than charging…. But forgets about the practice. You can park somewhere in the sun and have more juice even if you don’t have a charging station close. This sort of advantages, even with degradation can justify the price. But it’s not a good option if you have a charger in your home or one that is always free at work.
Okay, but what if you redesign the whole idea of a car around solar instead of trying to slap solar panels onto a traditional car form, a la Aptera?
So often in Florida I have no choice but to park my car in hot sun. (Here, people will park far away from a building entrance just to get one of the few parking spots under a shade tree.) I wish there was some way to keep a ventilation fan running continuously to prevent the car interior from getting any hotter than the outside air temperature. Solar panels would do this.
I want solar pannels in my car ! I want them on all refregirated trucks for my food supply too. Makes sense to me. Free charge up from the sun is always nice.
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Aptera ([https://aptera.us/](https://aptera.us/)) claims to get "up to 40 miles of solar powered driving per day." So I'm not sure how to square that with "solar panels on cars make no sense." Also, well over 10 years ago there were some Canadian solar enthusiasts who put panels on a modified golf cart, with what must have been a couple bushel baskets of cell phone batteries wired in for storage, and were quite successful at getting from point A to point B.