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Transportation

'Solar Paint' Being Developed By Mercedes-Benz Could Revolutionize EV Charging (mbusa.com) 222

"Mercedes-Benz is researching a new type of solar modules that could be seamlessly applied to the bodywork of electric vehicles," according to a recent Mercedes-Benz press release.

They describe the 5-micrometer coating as "similar to a wafer-thin layer of paste... significantly thinner than a human hair" — but creating an active photovoltaic surface with an efficiency of 20%. An area of 118.4 square feet (equivalent to the surface of a mid-size SUV) could produce energy for up to 7,456 miles per year under ideal conditions [based on daylight conditions from their testing in Stuttgart]. The energy generated by the solar cells is used for driving or fed directly into the high-voltage battery...

Solar paint has a high level of efficiency and contains no rare earths or silicon — only non-toxic, readily available raw materials. It is easy to recycle and considerably cheaper to produce than conventional solar modules. The Mercedes-Benz research department is currently working to enable use of the new solar paint on all exterior vehicle surfaces — regardless of shape or angle.

Solar paint could power 62% of the travel for a typical Stuttgart driver, their announcement notes. But in a sunnier city like Los Angeles, "It could be used for 100% of their driving, on average." (And "the surplus of energy could be fed directly into the home network via bidirectional charging.")

Mercedes-Benz researchers "initially thought the tech had limited scope for mass production," reports EV Central, "until experiments were carried out with prototypes coated with the paint in real-world scenarios. Instead of just coating the roof and bonnet to form a 1.8-square-metre surface area, one scientist suggested covering an entire car with the new solar paint, ramping up the surface area to more than 11m2. Another difference to the [Mercedes-Benz 2022 Vision EQXX concept] is instead of wiring the body panels to the 12-volt system, scientists hardwired the body panels to the Benz's high-voltage battery and the performance of the paint was well beyond expectations... Available in all colours, engineers admit the solar paint work best in darker shades. When it's launched, the tech should be as durable as regular paint. The photovoltaic surface is protected by at least two protective lacquer finishes to ensure it isn't damaged in daily use.
Mercedes-Benz says the solar paint could mean "increased electric range and fewer charging stops." And this is significant, because "Electric vehicle charging and infrastructure are two major obstacles to EV adoption on a mass scale," writes Autoblog — arguing that Mercedes-Benz "may have a solution... " Alternative methods of energy harnessing could help alleviate range anxiety, increase an EV's driving distance, and reduce charging costs across the board. Not only that but considering the cost of producing Mercedes' solar coating and the lack of rare earth metals, it could be the leading solution to charging concerns... While the German automaker says the solar paint isn't ready for production on a mass scale, research, and development are progressing at a steady rate. If all goes well, we'll hopefully see solar coating as an accessory EV charging solution within the next decade.
Thanks to long-time Slashdot reader schwit1 for sharing the news.

'Solar Paint' Being Developed By Mercedes-Benz Could Revolutionize EV Charging

Comments Filter:
  • "It's like getting 2 extra horsepower for free when the sun is shining."
  • by WilCompute ( 1155437 ) on Sunday December 08, 2024 @11:59PM (#65000291) Homepage

    Covering all of the car is nice, and 1K+ miles a year is also nice. Is it going to stop you from charging it? No. There isn't enough sun per sq. in. to cover usage for drivers between trips, in cities with large buildings and skyscrapers, you limit the amount of sunlight it can get during the day, in winter it is even worse up north.

    Depending on the area, there will be no ROI for using it vs regular paint.

    Still cool tech, and I would be much more interested in using it on housing, siding and metal roofs, carports and sheds. This would be a nice addition to solar for the home, or a standard feature for new builds.

    • by quintessencesluglord ( 652360 ) on Monday December 09, 2024 @12:32AM (#65000327)

      This is all or nothing thinking.

      Putting some extra distance between charges is extremely useful, as well as maybe getting away with a smaller battery, which has numerous benefits.

      It could be the difference between a 1 hour charge time and a 30 minute charge time to top off capacity.

      Just hope it is cheap/durable enough.

      • Just hope it is cheap/durable enough.

        It'll be fine until the first stone chip

        • by Freischutz ( 4776131 ) on Monday December 09, 2024 @03:41AM (#65000463)

          Just hope it is cheap/durable enough.

          It'll be fine until the first stone chip

          Sure, because one stone chip disables an entire solar panel ... wait a minute ... Donald? Is that you?

          • Solar paint coatings depend on multiple coatings with differing properties, when the paint gets chipped the environment gets in and starts to compromise not just the layers themselves but also their separation from one another. Repairs would be either impossible or at mininum exotically expensive as you have to sand through only specific layers of paint so as to expose sufficient area for the new paint to bond to.

            • Solar paint coatings depend on multiple coatings with differing properties, when the paint gets chipped the environment gets in and starts to compromise not just the layers themselves but also their separation from one another. Repairs would be either impossible or at mininum exotically expensive as you have to sand through only specific layers of paint so as to expose sufficient area for the new paint to bond to.

              If nobody's thought of this before, which unfortunately I guess they have, consider this a publication for patent purposes and prior art to anyone attempting to patent similar things in future.

              In the preferred implementation: Sand at a very shallow angle, all the way down to the metal or some specific layer like the undercoat. Now you have separated access to each of the layers. Measure the area of each and paint a new layer of each kind ensuring that you stay within the area covered by the layer underneath

              • In the preferred implementation: Sand at a very shallow angle, all the way down to the metal or some specific layer like the undercoat. Now you have separated access to each of the layers.

                Have you ever done automotive paint spot repair?

                • by Ol Olsoc ( 1175323 ) on Monday December 09, 2024 @09:36AM (#65000891)

                  In the preferred implementation: Sand at a very shallow angle, all the way down to the metal or some specific layer like the undercoat. Now you have separated access to each of the layers.

                  Have you ever done automotive paint spot repair?

                  I have - I helped a friend at his body shop right after High School.

                  The question is, or perhaps the assumption is - that one defect shuts the entire system down. I have a couple different solar panel setups at home. One is the crystalline, the other is amorphous. Crystalline is more efficient, but more fragile Amorphous is less efficient, but works better if the light is partially blocked or there are dings. Also flexible if needed.

                  So Mercedes is using an amorphous system for certain. The question is whether the paint system can be applied in a body shop environment. I'm doubting it. But we don't throw the baby out with the bathwater.

                  Another possibility is if it can be utilized as a "wrap", a vinyl appliqué as seen on mass transport buses. At that point, a whole new vista opens up. You might be able to change the color of your car, or design your own motif.

                  Then if in an accident, you replace or repair the damaged parts, then lay on a new appliqué wrap on the same, and there we are.

      • Putting some extra distance between charges is extremely useful, as well as maybe getting away with a smaller battery, which has numerous benefits.

        You're talking about a difference of approximately 5 kWh. A quick search of Amazon reveals you can buy a 5 kWh lifepo4 battery retail for about $1,000. Considering all the extra wiring and everything else needed to make a car covered in solar "paint" work, I'm gonna go out on a limb and say it's probably cheaper to just put in the extra 5 kWh worth of cells in the battery pack.

        For everyone who keeps saying it's somehow gonna make be make or break over whether you're gonna get stranded somewhere, just buy

        • Consider the problem that you take your car out into the back country, park it somewhere and go for a three week hiking trip. Right now, you end up with a low charged car which then gets worse the longer you stay out and probably fails terribly at the point that you get delayed for a week carrying your buddy with a broken ankle back to base.

          With this, not only can you trust that the battery stays charged, the longer you stay out the more chance there is that you will be able to get straight home. That sound

          • by necro81 ( 917438 )

            Consider the problem that you take your car out into the back country, park it somewhere and go for a three week hiking trip....With this, not only can you trust that the battery stays charged, the longer you stay out the more chance there is that you will be able to get straight home. That sounds amazing to me.

            Yes, it'd be pretty cool. But the use case you are suggesting is even more niche than the "I need to tow my 10,000-lb trailer 1000 miles every weekend, so EVs will never work for me!" The case fo

            • Yes, it'd be pretty cool. But the use case you are suggesting is even more niche than the "I need to tow my 10,000-lb trailer 1000 miles every weekend, so EVs will never work for me!" The case for EVs will not be made or broken by either scenario, because they're both so laughably at the extremes of typical usage.

              Sure. I absolutely expect this to be a quite rare high end feature at least to begin with. I'm sure most of the people that buy it will be paying mostly for the cool factor.

              Rather than adding hundreds or thousands more to an already expensive vehicle, I'd much rather see great ubiquity of charging infrastructure.

              In my particular case, when I decide I can sensibly switch to electric it would be something I'd be happy to add hundreds of pounds (dollars) , though certainly not tens of thousands of pounds (dollars) for. I already use my car so rarely that the problem of charging the battery (in a normal petrol car) is an important issue for me and

            • by swillden ( 191260 ) <shawn-ds@willden.org> on Monday December 09, 2024 @09:54AM (#65000925) Journal

              Yes, it'd be pretty cool. But the use case you are suggesting is even more niche than the "I need to tow my 10,000-lb trailer 1000 miles every weekend, so EVs will never work for me!"

              I think you're underestimating the use cases. Here's another: When I park my Tesla at the airport I have to make sure I remember to turn off Sentry mode, because if I don't it will slowly drain the battery. It will stop when the battery reaches 20%, but that's not quite enough to get home without stopping to charge.

              I would put a lot of value on the knowledge that while my car is parked the battery level is going up, not down, even if slowly. I have previously dismissed this idea, but the numbers from the article make me reconsider; covering the entire vehicle seems to be a significant improvement over just covering the roof and hood. This actually makes sense to me in retrospect; I have personally experienced the benefit of adding solar panels in locations that seem less than ideal, yet ultimately provide significant output.

              Related to your other example... one of the reasons I haven't bought an electric truck is because I do need to tow my 7,000 lb trailer to the mountains on a regular basis (I spend most of each summer there). Knowing that the battery would slowly charge while I'm camping wouldn't fundamentally change the calculations, but it would be reassuring. If it actually generated significant excess power, I might be able to stop burning propane for refrigeration and heating (the ~1kW of panels on the trailer cover other energy needs). Even without a solar powered truck, I'm looking forward to needing a lot less battery capacity in the trailer (currently about 5 kWh) because I should mostly be able to rely on the truck's battery; even better if the truck can supply not just nearly all of the energy storage, but a good chunk of the generation, too.

        • 5 kWh? I don't think so. Solar is roughly 1kW/m^2, assuming 100% efficiency and facing the sun. At best, you have something like 2 m^2 of usable surface area on your typical vehicle.
          • by habig ( 12787 )

            That's kW. Times Take a hit for efficiency in the 10's of percent. Then multiply by hours of sunlight in a day to get you kWh.

            5kWh in a day strikes me as optimistic but not ridiculous.

            Nice, but not a game-changer. And it all depends on how much more this costs you than regular paint. Although I suppose if you're buying M-B you've got more money than you know what to do with in the first place.

      • This is all or nothing thinking.

        Exactly! Also known as making perfection the mortal enemy of good. Or "Of what use is a newborn baby"

        Paintable solar cells! Beyond the automobile aspect, imagine entire houses or buildings painted this way.

        Anyhow, the metric used by some is odd. How much extra milage does it add while sitting in the parking lot, charging the car batteries? That does not compute. If it tops off the charge state, it has topped it off, not how much it adds to the RTE while moving.

    • by CaptQuark ( 2706165 ) on Monday December 09, 2024 @01:43AM (#65000373)

      Let's see, 7,456 miles per year is about 20 miles per day, on average. More in the summer and a bit less on cloudy days and winter daylight hours. I drive less than 140 miles per week since I don't drive to the office on weekends so that takes care of my normal driving needs. If I start the week with a full charge and park in the sun, I don't need to charge from the grid.

      If I drive more than 140 miles during a single week, then I still have just dipped into the 300+ miles my battery can supply. I can either wait a week for the excess charging in the sun to bring me back to 100% or I can charge from the grid or at work until I'm back to a level where I feel comfortable. I don't have to be at 100% every night just like gas cars don't fill their tanks as soon as they reach 7/8 on the fuel gauge.

      I can even see high-density housing units begin to offer parking on the roof to allow for additional charging options for those that can't get to grid charging. If the shadows from the building and surrounding trees limit sunlight, the roof might become the preferred parking location.

    • My only question is, once you've peeled the bodywork off and flattened it out and oriented it directly towards the sun to get the figures they're quoting, how do you go anywhere in what's left of the car?
    • Re: (Score:2, Insightful)

      by Luckyo ( 1726890 )

      There have been quite a few experiments on putting (significantly higher efficiency) solar panels on useful surfaces of an EV (that actually face the sun at a reasonable angle most of the time sun is up and car is not in a shade), and seeing how much it will generate. For example latest plug in hybrid Toyota Prius offers a solar roof as a functional option in a production vehicle from the factory. Smaller surface, but it's close to half of useful (sun facing most of the time at a good angle) surface of the

    • by e3m4n ( 947977 )

      Id be curious of the charge rate. Would eliminate ’running out of gas’ so to speak. Worst case scenario you are stuck somewhere for a few hours until you can drive 5mi to a nearby recharge station.

      • Id be curious of the charge rate.

        Slower than L1 charging. In fact, this takes an entire day of sunlight for what L1 charging can accomplish in 3 hours and 20 minutes. For the uninitiated, L1 charging means plugging an EV into the standard 120v outlets that are literally everywhere in the USA.

        • by e3m4n ( 947977 )

          its been 30yr since I was anywhere near LA, but I assume traffic jam commutes are still a thing there. So lets say your stuck in one of those for 1.5hrs every evening and possibly the morning commute as well. I assume there is still a battery drain since LA can be hot as shit and it takes power to run the AC. Would this at least cover the power required to run the AC so that your battery can focus on just driving? I would assume that could effectively extend the range back to its theoretical distances. I ca

      • 7000/365 = 19 miles a day.

        probably most of that is between 10am and 3pm, so maybe 2 miles charging per hour. The best case is you wait three hours and the worst case (somewhere around 4pm, depending on time of year and lattitude) is that you have to wait about 20 hours.

        In Europe, though, that's the difference between having to go around begging in a strange neighbourhood or calling a breakdown service and just parking the car, getting a bus home and coming back the next day.

        • by e3m4n ( 947977 )

          im always weary of quotes in miles since it makes a ton of assumptions. That assumes the vehicle is parked in clear view of the sun for an extended period of time. If you work somewhere that utilizes a parking garage, thats going to limit your exposure to just the amount of time you are actually on the road using it. But that does still have some potential. If one knew the theoretical charge rate in actual units of power, it would be possible to extrapolate the percentage of power demand it could supplement

  • by Powercntrl ( 458442 ) on Monday December 09, 2024 @12:06AM (#65000297) Homepage

    Great, let's add more crap to EVs to make them even more expensive to repair when they get into an accident. Or we could, you know, just put the solar panels on something that isn't likely to end up in a traffic jam, and hell, then they can even generates power for people who don't want to own an EV. Imagine that!

    Let's do some math here. 7,456 miles per year at the usual average of 4 miles per kWh comes out to 5.11 kWh per day. That's roughly 1/10th what these $120 solar panels [harborfreight.com] produce in a day. So, for $1,200 you can have the same amount of solar generating capacity and use it for whatever the heck you want. Things such as: running your heat pump, watching a whole bunch of Netflix on an extremely inefficient TV, mining cryptocurrency (I won't judge, much), or you could even use it to... charge your existing EV which has the old fashioned non-solar kind of paint job.

    I'm not sure why some "inventors" have this obsession with trying to cram solar in ill-suited places when there's no shortage of roofs that are currently sans solar. *sigh* At any rate, 5 kWh per day really isn't very much. That's less than an hour worth of charging at a free L2 charger, so if you already own an EV and happen to live somewhat near a free charger (both Target and Whole Foods have 'em in my neck of the woods), there you go.

    • by AmiMoJo ( 196126 )

      It's Mercedes. They don't make cheap cars.

      • by Viol8 ( 599362 )

        Unfortunately they don't make particularly good cars either at the moment. Cheap nasty interiors, lousy ergonomics and poor reliability.

      • by msauve ( 701917 )
        ITYM they don't make inexpensive cars. Cheap is another matter.
        • by AmiMoJo ( 196126 )

          Could be one of those Europe/US differences, but here Mercedes Benz are still reckoned to make good quality cars for the most part. Some of their EVs are interesting, some are stupid.

          The Japanese are lagging badly on EV tech, only Nissan really has a decent one but they aren't exactly competing with Mercedes. The Chinese are very competitive but availability is a big problem.

    • by Samantha Wright ( 1324923 ) on Monday December 09, 2024 @03:12AM (#65000437) Homepage Journal

      Or—and stay with me here—we could put solar panels on everything, including the cars, and drive the cost of the technology so far down that it's practically negligible, instead of relying on corporations to subsidize charging for the niche subpopulation that can already afford EVs.

      • by shilly ( 142940 )

        Fingers crossed! Thin film solar for building windows is another area where we could see this happen

      • by vlad30 ( 44644 )
        Actually this could be interesting if you could paint a house, Building etc the real question what is the price per square metre and what does the subsurface need to be
      • by smillie ( 30605 )
        I would like to see my metal roof barn painted with this stuff. The south side of the roof is 16 by 44. That would probably power a lot of my house, at least the coffee maker.
      • Or—and stay with me here—we could put solar panels on everything, including the cars

        This was the same argument tried with solar fricken' roadways. The problem is that currently there's still oodles of far superior places to put solar panels where the electricity they generate will always be put to use (unlike an EV which will just be sitting there generating nothing when the battery is full), and there is far less likelihood of the panels being damaged. After we've used up every good spot for solar panels, only then does it make sense to start putting them in less ideal locations.

        • You're arguing a false dichotomy. Is there a reason that solar paint application prevents solar panels from being installed somewhere else? Or, does installing panels on a roof mean someone cannot put solar paint on a completely different structure or object?

          Do you know if this paint uses a constrained resource that is also critical to solar panel manufacture? If not, there is no contention between the two, and they can be deployed in parallel without dependency other than budgetary concerns (which, if w

    • by Samare ( 2779329 )

      I think two big selling points are that:
      - it reduces the need to plug the car to charge it especially if you don't use it much like when you use it to get to a city then walk, use a bike or public transport and
      - it reduces the anxiety of being stuck in the middle of nowhere when the battery gets empty.

      You mean "*10 times* what these $120 solar panels produce in a day" by the way.

      • - it reduces the need to plug the car to charge it

        The article claims 20 miles of range per day. For all but the absolute shortest commutes, the car is still going to need to be plugged in. To be completely honest, if someone has a 20 mile round trip commute, they could probably do that on an electric scooter and save a ton of money.

        You mean "*10 times* what these $120 solar panels produce in a day" by the way.

        I meant to say that the panels produce 1/10th of that and kind of dyslexia'd it up. Slashdot doesn't allow post editing, so typos and brainfarts are just part of the experience here.

    • by shilly ( 142940 )

      1. The value of being able to passively charge while not at home is significant. The entire point of cars is that they're mobile, after all
      2. Panels are cheap, scaffolding and installation for domestic roof mounting is not that cheap.

    • by msauve ( 701917 )
      >Let's do some math here... 5.11 kWh per day. That's roughly 1/10th what these $120 solar panels [harborfreight.com] produce in a day.

      You fail at math.

      You're claiming a 100 W panel can product 50 kWh per day. Even if the sun shone 24 hours a day directly onto that panel, it would only produce 24 h x 0.10 kW = 2.4 kWh per day. But of course the sun isn't directly overhead 24 hours/day. Even if it's sunny every day, you only get ~5 hours of effective sunlight, depending on your location. So, 0.5 kWh/d
      • You fail at math.

        Nah, I fail at posting on this throwback of a site where you can't fix typos and brain farts after the fact. It's obvious from the $1,200 total that I meant to write that the panels produce 1/10th the required amount of electricity. But if you want me to say "my bad", I just did.

        But perhaps that's what you meant, and didn't proofread yourself. But the cost of a solar system is much more than just the panels, so you're still way off.

        Even if you add the costs of wiring hardware and various grid-tie paraphernalia, the bottom line price is still going to be significantly cheaper than buying a Mercedes-Benz EV. But my intent was wasn't to point out that it's a c

  • If the roof is 1.8m2, that's great.
    Covering the entire 11m2 area of the car isn't going to make it 6x better.
    At 11m2 I wouldn't be surprised if they counted the under-side of the car too.

    • by shilly ( 142940 )

      Jesus. It's Mercedes-Benz. They have proper engineers who actually build things and everything. They're not dumb as rocks, they know that the roof is the best bit of the car. But would you believe it, they actually did the work and found out that coating the less optimally exposed parts of the car was very much worthwhile, because the tradeoff of optimal positioning vs catchment area worked out well. It doesn't need to be 6x better, the point is that it can now supply a material fraction of many people's dr

  • Lol (Score:3, Insightful)

    by Valgrus Thunderaxe ( 8769977 ) on Monday December 09, 2024 @12:17AM (#65000307)
    You could cover the whole car with the most efficient solar panels and it's not going to make any meaningful impact on charging the vehicle.
    • Yup, and it isnâ(TM)t 1 April yet.
    • by Viol8 ( 599362 ) on Monday December 09, 2024 @03:42AM (#65000467) Homepage

      For commuting I use public transport and so my car is usually only used at the w/e meaning - if it were an EV, its not - it could spend the whole week (assuming sunshine) charging each day and offsetting quite a lot of charging. Atm I only do about 10K miles a year so a theoretical 7K for free would be a huge win.

      • a theoretical 7K for free would be a huge win.

        And that's primarily because EVs are astoundingly efficient. Even if you have to pay for the electricity, if you have a short commute the costs to "fuel" an EV are negligible.

  • Aptera (https://aptera.us/) is nearly in production with an efficient EV. The vehicle includes solar panel options, but they don't completely cover it. I wonder if this paint technology could further increase the daily range added from the sun beyond the 40 miles they're currently quoting?

    Info and videos: https://aptera.us/ [aptera.us]

  • Until the price tag is published, I'm sticking to my thin film solar cells.

  • by bradley13 ( 1118935 ) on Monday December 09, 2024 @01:12AM (#65000341) Homepage
    Those are some very optimistic numbers that assume your car is out in the sun a lot of hours every day. But OK, fine, as long as the "paint" is relatively cheap, why not?
  • I mean yes sure, you can make "solar paint" and harvest some energy. This can make a lot of sense on a roof or perhaps even on the back of a laptop, where you either have a large area or only need a small amount of power.

    However we are talking about cars, one of the least efficient pays of transport, particularly when Mercedes-Benz is doing it. They waste dozens to hundreds of kilowatts just to move a person. Gaining a kilowatt or two makes virtually no dent in that.

  • Weird how with almost every other type of technology, /. is like "sounds interesting, can't wait to see this implemented", but anything against fossil fuels and it's a tirade of "this will never work", "load of crap", "I'm keeping my old tech thanks".

    Kinda sus /.
  • Paint?! Where we're going we don't need paint!!! Everyone knows the solar panels should be placed in the freakin' roads!

  • Sure this tech is not perfect. But think about the inner satisfaction when you come back to the car, midday in a hot summer, with the sun hitting like a hammer, knowing that the car will be burning inside, but now knowing that at least it will have charged a whole lot in that couple of hours.

    • Better yet, some of that solar power could be used to run a ventilation fan making the car less of a solar oven. The Nissan Leaf already has this, powered by a small dedicated panel.

  • by bleedingobvious ( 6265230 ) on Monday December 09, 2024 @03:00AM (#65000435)

    Prediction bot: Next environmental disaster - highly toxic EV paint infesting every square inch of the planet.

  • Forget about cars (Score:4, Interesting)

    by Askmum ( 1038780 ) on Monday December 09, 2024 @04:20AM (#65000499)
    Can I apply this "paint" to the roof of my house and how much kWh would that generate?
    And not only the roof, also the outside walls. How easy is the application of this material?
  • Perovskite never ever, so I assume this is about pure colloidal quantum dot PV. (I say pure because they are more often used to sensitize other solar cells to more wavelengths.)

    If a German lab has managed to make a 20% efficiency CQD PV paint that's revolutionary not just for cars, it could make large scale flexible PV far cheaper. In the future PV will come on rolls.

  • solar f**king cars on solar f**king roads.. and they wont work for a lot of the same reasons. Solar needs to be at correct angle to the sun. So unless the paint magically deforms itself to orientate to point at the sun.. Then there is the rest of the car that is not in sun at all (ball park figure probably 60% - 70% of the car) Then there is heat, most cars get rather hot on the surface which always causes lower solar performance, and heaven forbid if you should drive in a city with lots of high rises bl
  • by msauve ( 701917 ) on Monday December 09, 2024 @05:36AM (#65000535)

    An area of 118.4 square feet (equivalent to the surface of a mid-size SUV) could produce energy for up to 7,456 miles per year under ideal conditions

    Reality check: 118.4 square feet is 11 m^2. Figure 1500 kWh/yr/m^2 direct normal irradiation [wikipedia.org]. Current solar panel efficiency currently tops out in the low 20%s (and they claim the same efficiency for this "solar paint").

    So, a flat solar panel of that size, steered to be perfectly pointed toward the sun at all times, would produce about 1500 x 11 x 0.20 = 3300 kWh/yr. A search pulls up that an average EV uses 0.346kWh per mile. 3300 / 0.346 = 9537 miles/year.

    The summary claims "energy for up to 7,456 miles per year under ideal conditions". I find that hard to believe.

    Instead of just coating the roof and bonnet to form a 1.8-square-metre surface area, one scientist suggested covering an entire car with the new solar paint, ramping up the surface area to more than 11m2.

    The shape of a vehicle is such that the vast majority will see solar irradiance at an oblique angle, and much of it will be in shade. You now have to also subtract miles for use of lighting, air conditioning (after leaving your car to charge in the sun!), heat, entertainment systems, etc. I call BS. Guessing "covering the entire car" includes the windows and underbody, and "ideal conditions" includes mirrors reflecting the sun from all angles.

    The Mercedes-Benz US PR blurb also converted units with no regard to significant digits. 118.4 square feet was obviously originally 11 m^2. 7456 miles, 12,000 km.

  • I suppose it's better than nothing, but few Mercedes owners would not also own a garage to park their car in. I would expect that owners in the northern part of the country wouldn't see much charging going on parked in a garage in the winter months.
  • 20% efficiency for a paint-on is ridiculous. We're 50 years out from that. They literally state if the sun could hit every surface at once, which it cannot. We only have one sun and it tends to point its light in one direction. And you don't even want to know what will happen if you continuously charge the battery packs for years at a time. Also, the Prius already tried solar panel trim and found out it works about as well as a battery float charger, which already exists, by the way.
  • Unless it's super expensive, you probably could think on painting the cheapest surface you can think of with it instead of cars.

    • For cars it's bullshit. I don't care what they're claiming, the available sun-facing surface area in optimal conditions with high quality solar cells is insufficient to maintain stored power on a car if you have even a modest commute.

      But tell me I can spray this on my home's siding and suddenly I'm intrigued.

  • But in a sunnier city like Los Angeles, "It could be used for 100% of their driving, on average."

    Just noting that an average of 100% means that every single instance achieved precisely 100%... so the words "on average" don't actually convey any information that wasn't already there.

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