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Is solar option on Cybertruck really feasible?

Is solar option on Cybertruck really feasible?

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.

https://www.youtube.com/watch?v=EAU01vhHMPw

PrescottRichard | December 6, 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.

TeslaTap.com | December 6, 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.

PrescottRichard | December 6, 2019

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.

Devilstower | December 6, 2019

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.

Misterbee6 | December 6, 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.

jlhm | December 6, 2019

Major difference between space with no air and gravity and doing the same thing on earth.

Darthamerica | December 6, 2019

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.

Tesla-David | December 6, 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.

FISHEV | December 6, 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.

Mark K | December 7, 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.

TeslaTap.com | December 7, 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.

El Mirio | December 7, 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.

Tesla-David | December 7, 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.

El Mirio | December 7, 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.

FISHEV | December 7, 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.

BumblebeEV | December 7, 2019

Feasible

However

Economically technically hard to optimise

Mark K | December 7, 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.

Mark K | December 7, 2019

= no one can argue

BumblebeEV | December 7, 2019

I think they will manage to make it happen easier than the FSD

Mark K | December 7, 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.

DAlexModel3 | December 8, 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.

Earl and Nagin ... | December 8, 2019

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.

Mark K | December 8, 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.

Darthamerica | December 8, 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.

Mark K | December 8, 2019

See above calculation. It should cost Much less per watt than rooftop solar. All done at factory, no onsite labor.

Darthamerica | December 8, 2019

Automotive grade electronics will cost more in my opinion... especially if it’s integrated into the truck rather than an attachment. Remember we are realistically looking at 10 to 15 miles a day in good locations during spring-summer months. It really starts to be a question of if it’s worth a few thousand dollars to enough people for Tesla to do this. We do this on space craft and vehicles that operate on other planets so there’s no question that it’s possible. But the economics given the use case. This is barely able to recover vampire drain with current solar efficiency. You might actually get more miles back from plugging the Cybertruck in to a 110V outlet on a portable generator.

Darthamerica | December 8, 2019

The good news is there are no technical reasons why it can’t be done.

Darthamerica | December 8, 2019

This is why I’m suggesting folding panels that can be optionally carried. If you know you’re going to park for a while you could take them out and charge if you’re in a place where that’s an option.

Earl and Nagin ... | December 8, 2019

@Mark K,
Economically, it makes more sense to put your solar panels on the roof of your home, business, or parking space instead of on the vehicle though. On the vehicle would work but probably not worth the cost since you need batteries anyway.
On the vehicle, on the highway, you take my ~100 miles per day and drop it down to probably 10 - 15 miles ($1 or $2) per day because you have less collection area and it won't be optimally pointing toward the sun most of the time.

FISHEV | December 8, 2019

"Economically technically hard to optimise"

Kind of like EV's.

andy.connor.e | December 8, 2019

@Prescott

I never thought of it like that before. Stuck in traffic means refueling. Thats unprecedented.

Mark K | December 8, 2019

Andy - Yes, if traffic is slow enough, you’d end up with more charge than you started with.

Just like starting a trip at higher altitude, and ending up more charged at the bottom of the hill.

Elusivejeep | December 9, 2019

I have been thinking a bit about this and I have a couple unsubstantiated theories.
1. I think it makes more sense to install solar on the home because it could then charge all your vehicles rather than the one it is attached to.
2. The cost of solar should continue to decline. By the time the CT comes out solar panels should cost 20% less than today. Perhaps they get cheap enough to install on vehicles. Imagine a tesla semi based RV with a solar roof.

TeslaTap.com | December 9, 2019

I believe solar cells are already a smallish part of a solar installation cost. You still need weatherproof glass enclosures for a panel, connectors, wiring, microinverters for a subset of panels or a single larger inverter for the entire system. Then there are costs for assembly labor, validation, and QA. A small percentage (if lucky) will have problems and these need to be repaired before release. Then you add a markup to cover your design efforts, production facility, robots, software, future warranty expenses and perhaps some profit at the end.

Darthamerica | December 9, 2019

No, you will not end up with more miles than you started with.

Mark K | December 9, 2019

Darth - If you’re crawling along in traffic at a few mph on level ground, you use very few watt-hours per mile.

That’s why max range is typically at around 15-20 mph. (Though it’s more fun to go fast in a Tesla).

At a certain speed, with large on-board PV surface area, your solar harvest could exceed watts you use, and then you’d actually accumulate charge.

Typically you wouldn’t. But under favorable conditions, it’s clearly possible.

You can’t ‘forbid’ Physics.

For bigger vehicles with the area of a semi trailer, it won’t even be so rare. Especially as cell efficiency improves.

If you drive a Tesla, you’ve probably done, or read about, a ‘hill-charge’ run.

At lower speeds, where there’s little aerodynamic drag, it’s pretty easy to demonstrate on a long incline.

Gravitational potential energy difference - aerodrag - friction - conversion loss = net charge gain.

Significant charge gain certainly isn't the typical case, but in the context of this theoretical discussion, it’s obvious.

It’s a necessary result of the Physics of the machine.

Darthamerica | December 9, 2019

@Mark I understood your original point and agree in principle. But in practice I think you're greatly overestimating the efficiency of commercially available solar technologies. BEVs are big heavy vehicles and it takes a lot of energy just to get them moving. You'd have to be sitting all day, literally, in traffic at high noon in Arizona. Your HVAC to keep cool would negate any potential solar gains. If such a system could be made to work then you may as well park the vehicle outside of your house and use it instead of a solar roof!

theradiobox.net | December 9, 2019

Don’t go expecting a solar charging Cybertruck to get all of its power from the sun; solar panels just aren’t that efficient.
Blogger at https://radiobox.net/

Darthamerica | December 9, 2019

Best case scenario assuming you get past automotive grade engineering challenges and cost would be; keeping the truck cool while you work, powering powertools while you work, recovering some energy lost due to vampire drain while camping/parked and as an emergency back up charging source if you're out in the wild too far from infrastructure to plug in. All the other stuff is science fiction for now.

wolfkinara | December 10, 2019

Hopefully this does not break any of the strict rules against photos/videos, the intention of this post is to discuss the autopilot issue, not to show off pictures.

Auto lane change has major issues. I know in the latest update they slow the car when the next lane is going slow, but autopilot will still accelerate into a collision path with a car that actually does pull out of another lane into the current lane! It not only completely ignores the blinker, it doesn't even "see" a threat until the other car is more than halfway into the lane, when a reasonable human would abort as soon as the car starts to cross the line or turns on it's blinker.

This is extremely dangerous, the car needs to make sure when I'm changing lanes to the lane to the left, it first makes sure there's no cars coming from the right into my current lane, especially if its going to be accelerating. It needs to make sure there's no cars 2 lanes to the left moving into the left lane, before it crosses over into the left lane too!

Forget robo-taxis, basic safety threats like this need to be addressed! There's no way auto pilot is "safer" than a human driver in it's current incarnation! If I had not taken over, I would have crashed.

There's no logical reason why the car should not abort the lane change & start to slow at 0:08, or 0:09 at the latest! As soon as the car next to me has its blinker on to enter my lane in front of me, the tesla should optimistically leave an appropriate buffer for the car to enter the lane, not speed up & begin the lane change on a collision path with the other car changing lanes! Or at 0:09 when the car actually enters my lane dangerously close in front of me, the tesla should emergency brake or slow down! Or at 0:10, the car is fully in my lane & brake lights are ON, my tesla is still accelerating into it! Or at 0:12, the car is clearly decelerating in front of me even if the brake lights did not work, the Tesla still doesn't see the threat. At around 0:13~0:14, emergency braking did kick in, but I had already manually applied the brake at that time.

Darthamerica | December 10, 2019

You're in the wrong thread.

andy.connor.e | December 10, 2019

"I think you're greatly overestimating the efficiency of commercially available solar technologies."

Good thing Tesla is not manufacturing generic commercial solar.

Darthamerica | December 10, 2019

@Andy then it certainly won’t happen due to cost.

andy.connor.e | December 10, 2019

We will have to see what the price is before making that assumption.

SamO | December 10, 2019

Yes people won’t buy overpriced bullshit like a Rolex when a Times exists. /s

SamO | December 10, 2019

Timex

andy.connor.e | December 10, 2019

Dont you get me started on diamonds and jewelry.

jimglas | December 10, 2019

first one is free

andy.connor.e | December 10, 2019

Designer clothing? People waste money like you cant believe.

Darthamerica | December 10, 2019

Yet some of you, not Andy, drive $100K EVs? Seems hypocritical.

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