• Kbobabob@lemmy.world
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    1 year ago

    The road-legal car has a top speed of 145 kilometers (90 miles) per hour. On a sunny day, its battery range is around 710 kilometers (441 miles) on roads, and around 550 kilometers (342 miles) off-road, depending on the surface. In cloudy conditions, the team estimates the range could be 50 kilometers less.

    This actually seems pretty good. I suppose those numbers would go down over time and depending on how dirty they are.

    • MooseBoys@lemmy.world
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      1 year ago

      That’s by draining the battery, not by sustaining a charge. If it gets 710km in the sun and 660km in cloudy weather, it probably gets 610 without any solar panels at all.

    • CmdrShepard@lemmy.one
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      1 year ago

      Wait, someone above stated that this took them a week and half of travel time. If they could go 441 miles on a single charge, why did it take them an additional 8-9 days to accomplish the remaining 179 miles?

  • JJROKCZ@lemmy.world
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    1 year ago

    Ugly as sin but I’m down if I can drive it mostly solar and plug in when needed in a more temperate climate

    Edit: I feel like a lot of you are forgetting it just needs to get you to work, where it sits in the sun for 8-12 hours, then home where it can be plugged into homes or left outside for non-homeowners. If it can build enough charge during that work parking lot for me to get home and then top up on the home charger, that’s a huge plus over just plugging in and eating grid energy all the time. I’m not expecting the thing to have no battery and just convert sunlight to movement like magic jfc….

    • Ilovethebomb@lemm.ee
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      1 year ago

      You wouldn’t, there is actually very little energy in solar for an array the size of a vehicle roof, and it would likely take days to recharge.

      • JJROKCZ@lemmy.world
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        1 year ago

        I can’t YET, this is clearly early technology, in a few years who knows. Remember we went from not being able to fly to landing on the moon in a lifetime

        • Ilovethebomb@lemm.ee
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          1 year ago

          The problem is, there just isn’t that much energy in sunlight, so even a perfect solar panel that captured 100% of the sun’s energy wouldn’t get you very far.

        • vrighter@discuss.tchncs.de
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          1 year ago

          nope. not “yet”. just not physically possible. even with 100% efficient panels.

          There just is not enough energy in the sunlight hitting the car. You would have to somehow make the sun shine brighter. Which is not really possible.

          • Phen
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            1 year ago

            The amount of power is limited, but can’t the tech improve to make cars that require less power?

            • vrighter@discuss.tchncs.de
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              1 year ago

              you can make the engine more efficient, but at some point there is a minimum amount of energy needed to get the thing moving and they are already quite close to fully efficient. To reduce energy needed any further you can make the car lighter, but that obviously cannot be improved indefinitely.

          • Gsus4@mander.xyz
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            1 year ago

            Wait wait, how are you calculating that? If you take a generic sea level solar irradiance of 6kWh/day/m2 and let’s assume the car has a solar panel area of 3m2 (probably more, but maybe not all exposed at the same time) with a solar panel efficiency up to 30% and the cosine for solar angle (say ~0.7), given the best 0.137 kWh/km around, that gives around 30km a day. That’s already enough for my weekday return commute.

            All this neglects shade, cloudy days, won’t work for all latitudes…but it can also be upgraded with improved battery storage/weight, improved solar panel efficiency and maybe even the area of the car top and shape of panels can be improved (e.g. make them extendable/orientable when parked). At worst, you just top it up to 500km from the grid every weekend and that will make up for the difference over the course of the week.

            • Waraugh@lemmy.dbzer0.com
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              1 year ago

              I have a golf cart I use for most of my short drives. I’ve been thinking about putting solar on the roof and figuring out how to do all these calculations so I can decide if it would be worth it based on my use case. I like to keep it in my garage out of the weather when I’m not using it unfortunately. Feel like it will last me forever if I take care of it like that instead of leaving it outside and in not sure if Solar would be worth it for while I’m driving or out at the store or visiting someone.

        • BassTurd@lemmy.world
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          1 year ago

          I’m not very well versed in solar tech, but what I think I know is that we’ve already approached about the max efficiency out of solar already, so there probably won’t be large gains going forward.

          • TonyTonyChopper@mander.xyz
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            1 year ago

            silicon solar panels are at their limit which is something like 30% efficient. Newer chemistry will go beyond that but as the other comment said even with double the power there isn’t enough energy in sunlight for a car sized panel to get a car going for too long. Especially when there are clouds out (most of the time here)

    • magnetosphere@kbin.social
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      1 year ago

      Well, I wouldn’t expect a bunch of engineering students to be on the cutting edge of style anyway, so I’ll cut them some slack in that department.

  • ShortN0te@lemmy.ml
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    1 year ago

    There is no actual information on how self sufficient the car actually is. There is only 1 number which states how long the car drives on a sunny day with solar+battery combined.

    The car probably needs to charge for days via the solar panels in order to fill up the battery.

    • SomeoneSomewhere@lemmy.nz
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      1 year ago

      In cloudy conditions, the team estimates the range could be 50 kilometers less.

      In other words, the solar only adds about 50-60km/day to the battery.

      Another case of putting solar panels on specific things not being a great idea. Chuck the panels on a convenient surface pointing at the sun and connect them to the grid. Connect your load to the grid. Job done.

      We can talk about solar windows/roads/cars/rivers/canopies when we’ve run out of space on houses and commercial roofs. They already have grid connections, structure, and are protected from damage.

      • blazera@kbin.social
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        1 year ago

        the solar only adds about 50-60km/day to the battery.

        How do you say that so nonchalantly

        • SomeoneSomewhere@lemmy.nz
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          1 year ago

          Compared to the 700km claimed range (which seems very optimistic), that implies you would need to let the car sit for two weeks to charge on solar alone - more if the weather is not totally perfect or there is any shade.

          So if you’re wanting to do a multi-day road trip, it’s of stuff all use. You’re going to be relying on the big battery and the grid; the solar is a rounding error.

          If you’re planning to do <50km/day commuting/shopping etc… please don’t get an off-road SUV tank, and probably not anything with 700km of range. Get something that weighs half as much and put 5x as much solar on your roof. It’ll still be cheaper overall and the panels will last longer.

          If you’re actually in the small segment that needs off-road capability and an SUV (say, a farm run-around), congratulations. Definitely don’t get a car with solar on the roof because it will immediately be covered in dust, and the minor dents and whoops-a-small-tree-fell-on-it will break the panels in the first year. You also probably want to park it in the shade wherever possible.

          Again, stick 5x the panels on the garage roof and get something cheaper.

        • SomeoneSomewhere@lemmy.nz
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          1 year ago

          Even if you’re off grid, it’s still better to put the panels and most of the battery on a house.

          You’ll get much better yield because the panels can be pointed in exactly the right direction and won’t be covered in road dust, plus there’s far more space available.

          Putting a smaller, lighter battery in the vehicle is going to reduce its energy consumption, as is using a shape designed for low drag rather than a shape set up for optimal solar.

    • blazera@kbin.social
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      1 year ago

      Yeah, nothing on how much is pre-loaded battery and how much is solar charging, or how long the trip was.

      • chowder@lemmy.one
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        1 year ago

        None. It was entirely solar based. This is their 2nd vehicle smaller and lighter than the camper they made. So 440 ranged is fully charged, otherwise 620 miles in a week and a half off of just solar.

        week-and-a-half-long experiment

    • vrighter@discuss.tchncs.de
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      1 year ago

      there doesn’t need to be. It’s not. plain and simple. There just isn’t enough area on a car’s body (remember, most of them won’t even be oriented properly most of the time) for panels to generate enough power for self sufficiency. Even if the panels were 100% efficient. This will always be the case for any solar car.

        • vrighter@discuss.tchncs.de
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          1 year ago

          assuming average conditions, somewhere on the order of 20 kw at cruising speed. More is needed to accelerate.

          On the earth’s surface, we get about 1kw per meter squared of energy from the sun. That’s before factoring in inefficiencies in the panels, inefficiencies due to panels not oriented correctly, the battery charging system etc. Actual usable energy generated is significantly less than that.

          So, with 100% efficient panels, you would still need, in theory, at minimum around 20 meters squared of perfectly efficient, perfectly oriented panels. Probably about 3 to 4 times more, in practice. There just is not enough surface area on a car.

      • HughJanus@lemmy.ml
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        1 year ago

        I mean that’s just not true unless you’re referring to the very narrow scope of powering itself while driving down the highway at 70MPH.

        With a sufficiently efficient design and enough solar panels and sun exposure, like can be seen on the Aptera, you can get 30-40 miles of range/day, which is more than sufficient for a daily commute.

  • Immersive_Matthew@sh.itjust.works
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    1 year ago

    How on earth can they get that much solar area power on a car? Many others have tried and it has always said there is just not enough space on a car to generate the amount of solar you need less ultra light, impractical cars. Feels like BS especially since there are no details.

    • chowder@lemmy.one
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      1 year ago

      There is no bullshit. they claimed 620 miles in a week and a half off of just solar power. The converter they used is 97% efficient. They just hid the week and a half travel time.

      • CmdrShepard@lemmy.one
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        1 year ago

        If I calculated this right, assuming it drove continuously, they were only able to travel at around 2.5MPH with this thing?

        • tankplanker@lemmy.world
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          1 year ago

          Most likely the car was parked during the day and charging from the sun as it would take hours to charge even a small battery. They then drove at night/early evening/late afternoon over a couple of hours at around 30mph until the battery was empty and repeated.

          If it was 10 days of driving with an average of 62 miles a day, that only needs to be a very small battery even compared to even a gen 1 Renault Zoe that has 22kwh. They could probably get away with 15kwh or so (approx. 4 miles per kwh), which would make charging it off car sized solar panels possible in a day.

          Majority of Europeans only do very low daily mileage. The UK journey average is only 8 miles. So this car works for those sort of use cases, although there are always going to be outliers who need more, so good job there already cars that cover them.

          • erwan@lemmy.ml
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            1 year ago

            Yes, if you park it outside in a sunny area. Which in a European city would be tricky because it would most likely be parked in a garage, or maybe street parking to get that sun but even then it would be under the shade of buildings most of the time.

            Bottom line - if you want to charge your car with solar, you’re better off charging at home with solar panels on your roof. And maybe a home battery to charge during the night with electricity generated during the day.

            • tankplanker@lemmy.world
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              1 year ago

              Well there is a reason this was done in sunny Morocco rather than rainy Britain.

              However even in shade you’ll still generate electricity, just not as much.

              I see this is inline with this being more of a range extender the same as good regen for those that can’t get full sun all the time. I get between a quarter and fifth back from regen, if I can get that again from solar then that’s huge.

              Personally I won’t touch panels in the UK at present because the yield from the number of panels you can actually fit on an average UK roof is just pathetic over a full year. We need greater efficiency to make it work, which would also benefit cars like this.

              The idea of a separate house battery is a good one however anything of decent size for whole home when you have cooker, heat pump for heating and water, the cost of inverters, plus EV charging being a few 10s of kwhs (we do between 300 and 400 kWh between three cars every month) is just a non starter in the UK for the average home. They would need too large a battery and need a huge amount of solar to charge it, we just don’t have the room or return on investment.

              It makes more sense to use the very large battery you already own on the car and do it that way. Charge at work using their solar and return it back home.

        • sugartits@lemmy.world
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          1 year ago

          I imagine the car wasn’t moving for the entirety of the 2 and half weeks. Drivers probably had to sleep.

          • CmdrShepard@lemmy.one
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            1 year ago

            Even accounting for 10 hours a day to rest, that still only comes out to an average speed of 4.4MPH over 10 days. This is obviously mostly charge time I’d imagine, but you still need to account for that time when you’re embarking on a trip.

            I’m curious how much of that really is charge time. They may have left it charging all through the daylight hours and then drove 60 miles every evening.

  • totallynotarobot@lemmy.world
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    1 year ago

    Misread headline as “world’s worst off-road solar suv” and thought, “it’s nice there’s enough competition in this space for there to be a worst one.”

  • 𝒍𝒆𝒎𝒂𝒏𝒏@lemmy.one
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    1 year ago

    Impressive work by the students IMO, a 1200kg EV campervan that achieves a realistic range extension with its solar power roof. Great to see that this is even possible with current solar tech though - I wonder what something like this would look like in the future with more efficient panels.

    Let’s say this matures, what would be the stand out differences between something like this, and a normal combustion vehicle? The main advantages the combustion has would be really good fuel density (longer range) and no waiting on the batteries to recharge, however the solar vehicle is much more lightweight (harder to get stuck, as mentioned in the article) and requires almost no maintenance… maybe just dusting off the panels after driving through a sandy region

    • emptiestplace@lemmy.ml
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      1 year ago

      I believe they were comparing the weight to a conventional electric vehicle, not an internal combustion engine.

    • nymwit@lemm.ee
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      1 year ago

      Did you see the pictures? It’s like the size of a sedan. Campervan seems a stretch.

  • MrSqueezles@lemm.ee
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    1 year ago

    uses “lightweight and robust” composite materials to cut weight

    Pretty great as an experiment. I wonder how this would fare in crash tests, whether there’s a way to make composites work in practical scenarios.

  • nymwit@lemm.ee
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    1 year ago

    This is a neat project…and terrible reporting.

    Did they start out with any charge? How long to charge it fully via solar? How long it took them to do their trip? You could easily read this and think they did it by driving the full range (one of the few stats they give) out every day unless you’re knowledgeable enough to see what they’re not telling you. Is that range at 30mph? People are reading range figures and thinking, “well, gee, the EVs I can buy only do X and this does Y!”, which isn’t comparable at all without how that range is defined. If those figures shouldn’t be compared to regular cars, then say it in the article! This is a 20-30 mile a day charged-by-solar-in-the-desert-near-the-equator vehicle, which isn’t nothing, but not really as presented. Greenwashing (it’s probably not) or whatever this should be called doesn’t help the needed planetary shift away from fossil fuels.

    Looking for other reporting (where are other commenters finding the duration of the trip?):

    Guardian - no mention of time.

    bonus: “We hope this can be an inspiration to car manufacturers such as Land Rover and BMW to make it a more sustainable industry. The car was actually very comfortable in the off-road conditions as it is very light and does not get stuck.”

    Remind me how it was so lightweight again? Does it have LR & BMW level noise damping? It surely had AC and all that right? I don’t know because that info wasn’t provided. You don’t need to convince LR and BMW, you need to convince consumers to go without those.

    Daily Mail - no mention of time

    Designboom - no mention of time

    Jalopnik - no mention of time, which is disappointing for a car specific site

    This is a cool project and it’s cool university students did it, but why leave out such a misleading pieces of information? It’s bandied about as a “showing people it’s possible” thing as in, “you could have a solar car!”, but leave out all the bits that really make it possible, like forgoing AC or the daily miles driven. That none of the reporting on this has this information either means [puts on tinfoil hat] it’s a vast conspiracy to make green stuff look more palatable [tinfoil off], it’s all confluence of interest in making it look more palatable, or the information just wasn’t given out, or they’re all referencing the same source news-wire style. Frustrating.

    Where’s the real information? I feel like we’re in a race against time to move away from fossil fuels so things like this need to not be misleading.

    Edit - I’m stupid, it does say week and a half long…which only proves the point I think in not contextualizing range and such, because that’s a long time

  • unconfirmedsourcesDOTgov@lemmy.sdf.org
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    1 year ago

    Okay now imagine a future where we’re able to beam power down from space, which is something the air force is working at this time.

    I know it’s probably not viable for a million reasons but how cool would it be if this tech truly is viable and the air force is able to develop it to a point where they can start offering it to the public, to support infrastructure, such as in-transit charging, or even just to support rural applications like farming? Would probably help with climate change at least.

  • zloboslav@lemm.ee
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    1 year ago

    But why do they keep making those eco concept cars look so goofy? Wouldn’t it be better marketing if it looked cool instead? I don’t get it…