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Is solar option on Cybertruck really feasible?

edited November -1 in General
Shortly after the Cybertruck's reveal, Elon Musk tweeted about an option to add 15 miles per day through solar panels, with the possibility of double that number with add on "wings."

But is that number really possible? As it turns out ... yep. Absolutely. Even if you use some pretty conservative numbers about the efficiency of the panels and the whr / mile of the Cybertruck.

Here's a pretty spiffy video from YouTube that goes through the math, but basically, if the Cybertruck is 60% as efficient as the Model 3, the numbers are almost dead on.

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Comments

  • edited December 2019
    That would be handy. If you’re stuck in traffic because of an accident you’d prolly come out of that with more E in your tank.

    I was thinking of a different solar solution, this one for ‘off reading’ or remote dirt road driving. In a perfect world I could see destination chargers taking on a whole new meaning - solar powered / battery stored energy out in the middle of nowhere un-connected to the grid.

    Sadly you just *know* they would be vandalized were they located that far from civilization.
  • edited December 2019
    I'd love for this to work, but I have major doubts. It may be technically possible, but not likely being practical from a mechanical and cost standpoint.

    To convert the aluminum roll-up cover into a wide 50" x 5" sections of glass/solar/aluminum, that are electrically connected together, and is able to roll up sounds like a huge nightmare. Making it reliable for a long period seems very doubtful. Because these are strips with hinges between each panel, you will immediately lose 10% or more of the surface area too.

    Then there is the cost. Because it has to withstand a far more harsh environment, I'd estimate the costs are going to be three to four times that of a home solar-paneled roof. A $5K cost would seem to be the bottom end, and it could be quite a bit more. Most solar projects are rated on payback. For home solar, the payback can be as little as 3 years, but rarely more than 10 years. Some earlier thumbnail work I did showed that if the solar vehicle roof was in the sun for the entire day, every day, 365 days of the year, the payback on a $3K system was over 100 years. The more expensive the system, the worse the payback. Now that was based on a flat roof, which means the angle is not ideal, but vehicle orientation does not matter. With the Cybertruck, you can get maybe 15% more solar output if you orient the truck perfectly with the maximum sun. The likelihood of that happening every day is slim, and if you're parked in the totally wrong orientation, the output will be far less than optimum, possibly zero.

    The idea of wings that spread out seems even more far-fetched. Space-X does it to collect solar energy in space, but these are million-dollar contraptions. Ignoring the cost, again the mechanics of making something reliable at a reasonable price seems doubtful. Then I wonder if owners are willing to forgo most bed space by having this folding solar cell contraption.

    Anyway, Tesla has never committed to solar on the Cybertuck, only that it would be a cool option. When the costs are analyzed, I just don't see it happening.
  • edited November -1
    Damn you and your reality based arguments TT!

    Someone has a solar panel covered car that was announced in the last year or so, can’t remember which one it was but there was a connection to a solar challenge winning team. Think the team was in Northern Europe and the challenge was in Australia.

    Was there some tech out there where windows were also solar cells? This may not work on a vehicle but that’s another potential area for collection. Of course if it’s a window than it isn’t collecting a lot of solar and can’t lest it become a thin wall.

    The tech is one thing but the orientation part of the equation is a very good point. Parking lots are not designed (today) with that in mind. How cool would it be to park at the airport for a few days and arrive back with more Es than when you parked?

    My idea of off road destination chargers could take all that into account, but overcoming the vandalism risk is the Achilles heal on that one. Damn human nature.
  • edited November -1
    Just a few comments:

    - Fold up, fan out, and otherwise collapsible solar panels of all types are common. Check out any camping store. The voltage carried by individual comments is quite low, making contact connections pretty darn simple. I don't see any concerns about creating panels that ride on top of the louvers. Having just gone through an electronics project, I can say it's also simple to order custom sized panels ... and Tesla makes their own.

    -- Modern panels are available that are both flexible, thin, and impact resistant at low cost. These panels are also only about 3mm thick so might not require much in the way of specially engineering the louvers.

    - Of course the area of overlap would not be included in the calculation ... and it's not. Only the exposed surface.

    - The amount of solar power we're talking about here is far less than you can currently buy for $1000. In fact, Just looking at the whrs, you could buy the whole system, controllers and all, for about $500. This is far smaller than a home roof installation which would be expected to produce many times this amount of power.

    None of this doesn't mean it won't be a $5k option ... because it will probably be a $5k option. But the actual cost of the components, even at retail, would be much less. And again, these guys make the stuff. So offering a $5k solar option is probably a very nice margin for them.
  • edited December 2019
    I was a little skeptical about deploying solar wings, too. Then yesterday I watched the latest SpaceX launch of the Dragon capsule. About 40 minutes in, I saw the Dragon capsule seamlessly deploy it's solar array. I think they have got this figured out. If SpaceX can do it on an object moving in space, Tesla can probably simplify it enough to work on the ground.
  • edited December 2019
    Major difference between space with no air and gravity and doing the same thing on earth.
  • edited November -1
    It's possible, but I agree with others doubt about it being practical. The cost alone would not justify it except for bugout and prepper situations. That's a limited market so it's questionable if Tesla will modify the design to include that. I could see an accessory that you can carry if needed in the cargo bed.
  • edited December 2019
    I agree with your assessment @Devilstower. Having this option for my Cybertruck Is a no brainer for me. Don't see why it would not be practical.
  • edited December 2019
    Solar glass option on Model 3 is what Tesla should offer. A solar PV glass roof would be a 28” x 85”. At 30kWh per year per foot should generate 566kWh in ideal conditions. 400kWh average. 1,600 miles of solar power a year right on the car.
  • edited December 2019
    Summary reasons why this will indeed work -

    1. The engineering is possible. Nontrivial, but doable. See calc’s on related thread below.

    2. Elon already committed to it. His track record on final specs beating promises is consistently good.

    3. Practical solar harvesting on-board is strategic gold. It’s a killer disruptive benefit.

    Stuff often takes longer than his stretch goal, but he never wimps out on delivering even better performance.

    Compared to FSD, this is a far more modest technical challenge.

    The question is not if they will do this, but rather, how far they’ll go with optional wings and other optimizations.

    Going from 15 miles per day, to 40 mpd, reaches a critical threshold for daily use-cases.

    https://forums.tesla.com/forum/forums/cybertruck-solar-option-power-life

    This opportunity is so potent to change public perception, Tesla will not shrink from the fight to make it.

    A new category of SEV’s - Self-Energized-Vehicles, will intensify the disruption already underway.

    CT is the logical starting platform, because it has the largest planar surface area.

    But PV tech itself will materially advance too, with multilayer wide-spectrum coating stacks, and window coating.

    Later on, PV harvesting will get integrated across many other vehicles.

    Someday, not too long from now, we will consider it ridiculous to own a car that can’t produce any fuel.

    This is an iconic advance that will make it overwhelmingly obvious to stop buying gasoline.

    Tesla has all the necessary competencies to totally own this space.

    Just as with the strategic genius of the radical design of the truck, the notion of Self-Energizing is so shocking, it will wake everyone up.
  • edited December 2019
    @Mark K - I love your enthusiasm, but coming back down to earth:

    1) While engineering may be possible, the costs are likely to doom this idea. Just because something can be done, doesn't make it marketable at every price point. I think most are underestimating how complex and difficult this would be to meet automotive standards for longevity, reliability, and strength at an affordable price point.

    2) Elon has not committed to it at all although there are various tweets from others seeming to believe it. I can't find his original tweet, but he basically answered another poster asking about solar on the Cybertruck. Elon only stated it was possible. Zero commitment or cost estimate from Elon.

    3) I don't see it practical yet. If practical, yes it would be fantastic.

    Even if such a solar array is in the rollup cover, it is likely to produce far less than 15 miles of range per day. That's for optimum conditions using the best cells available today, having 10+ hours in the sun, located close to the equator, being perfectly clean. and oriented directly at the sun. It may even need the truck to be moved 4 or 5 times during the day to keep the optimum sun, but perhaps autopilot can move the truck for you!

    The truck is already quite impressive, but sorry to damper expectations on this solar idea.
  • edited December 2019
    @TeslaTap Elon stated "It will be an option to add solar....", question is, did he mean an option for them to eventually offer or a planned configurable vehicle option. I think it will be the later, and even at a high price point desirable for some people.

    The truck can act as a self sufficient power bank, which one can plug into the house and use in emergency situations, which i think customers might go for to keep freezer and fridge running intermittently during severe outages.

    Installing a permanent emergency natural gas generator goes for $8 to 10k and people install those all over Texas, PV on the truck might not generate same level of power, on the other hand it is mobile and you can move it with you if you change properties.
  • edited December 2019
    @Mark K, totally agree with your list of reasons it will work. Moreover it is definitely in line with the Tesla mission to transition to renewable energy and transportation. I want my CT to have this option available to make it as energy independent as possible. I am hopeful that EM will make this a future option for the CT. Moreover, I have been following Solarwindow.com, which is a company working on solar embedded windows (https://www.solarwindow.com/2017/06/watch-technology-cctv/), which could dramatically transform windows on buildings and possibly CT into solar producing products.
  • edited December 2019
    If push comes to shove, Tesla should at least offer flexible foldable solar mats as an accessory to plug into the car, unlocking the use for solar storage and inverter use.

    These large solar mats already exist.
  • edited December 2019
    " Practical solar harvesting on-board is strategic gold. It’s a killer disruptive benefit."

    Musk does not agree and has always been dismissive of putting solar PV glass on Teslas even though it fits the Tesla mission, Tesla sells solar PV glass and benefits are substantial, 1,600 miles of PV glass roof generated power a year.

    That's 100 hours of full blast 4kw an hour heat.

    Probably a bit more as it would also help provide shade in summer reducing AC load while helping to power car.
  • edited December 2019
    Feasible

    However

    Economically technically hard to optimise
  • edited December 2019
    The tiny solar ‘sunroofs’ on Prius and Fisker were a joke, and that’s what Elon had dismissed.

    CyberTruck’s opportunity surface area is about 10X, which is why Elon posts a different perspective now.

    The arguments against are that it’s ’too hard’. Hard, is exactly where genius shines.

    Once achieved, no one can’t argue that getting your daily fuel for free isn’t desirable.

    CT is evidence that radical thinking is absolutely leveraged in Tesla’s playbook.
  • edited November -1
    = no one can argue
  • edited December 2019
    I think they will manage to make it happen easier than the FSD
  • edited December 2019
    Fishev- notice that Elon is now talking in terms of miles per day, or mpd. Not kWh, but net, usable, mpd.

    That is the meaningful metric, which defines the benefit proposition.

    Elon is already talking in the 15 - 40 mpd range. He knows the strategic opportunity quite well.

    40 mpd is the threshold where the machine can fuel itself for most use-cases.

    Ranchers and contractors are very meat and potatoes businessmen, and very economically rational.

    They simply won’t keep burning $500 a month in gasoline, once they have this choice.

    That is what is so scary to the fossil fuel sponsors and their proxies here.

    CT with solar will be the first proof of practicality. Their true, lower monthly bills, will be inarguable.

    Consumers will then demand the same for other platforms.

    Those are harder to do, but will ultimately yield to advances too, because the demand is there.

    No one wants to pay for gas if they don’t have to.

    Old habits may die hard, but the shock is all the more stunning when the do.
  • edited December 2019
    I'm skeptical. Sunlight throws about 1kw of energy per square meter on ground, best case. Solar cells are typically less than 25% efficient. So if you have 2 square meters of solar cells, that's < 500 watts per hour in the middle of the day under perfect conditions. My home charger normally works at 7kw per hour, 14 times as much. So, I guess it's possible, but hard to see whether it is practical/cost effective.
  • Having done a few successful and 'in-progress' things with solar in our day jobs, I'd like to propose that solar on the CT will probably do zero good for urban usage. The energy provided by solar in the area of a CT is just too small to be competitive with the electric grid. However, as @PrescottRichard proposes, it could be a savior for off-grid uses were more convenient options don't exist. On an remote hiking, hunting, fishing, military, or scientific expeditions to extremely remote areas, being able to collect even a few miles of range per day while parked could make operations far more convenient.
    Assuming the CT's nicely sloped vault roof provides ~6 square meters of collection area. If one were to unfold panels on the sides, one could conceivably get 18 to 24 square meters while parked (and fishing, hiking, etc). At 1 kw/sq m and 25% efficiency (which is feasible today), one can get between 4 and 6 kW peak. over a day, that's about 36 to 48 kWh per day or ~100 to 150 miles per day, depending on time of year, orientation, ability to change orientation, etc.
    That's quite significant.
  • edited December 2019
    Earl and Nagin ... agreed, no sun = no power.

    There’s no use for onboard solar in Manhattan. Neither do we see many folks driving F150-sized vehicles in Manhattan traffic.

    However, If you park where sun shines, or even drive on unshaded freeways like we have in Los Angeles, you’ll get a harvest.

    So for suburban or ranch use, 40 mpd, passively for free, is a game changer.
  • edited December 2019
    Hmm... @ $3 per W for residential, this may be even more expensive. Easily $2500+. It can be done but it’s just hard to see it as cost effective. Regardless it’s cool idea and I hope they make it work.
  • edited December 2019
    See above calculation. It should cost Much less per watt than rooftop solar. All done at factory, no onsite labor.
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