Check Out Tesla Cybertruck's Unique Solar Charging Tonneau Cover

JBee

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I don't see how the tonneau is smaller than the roof window.

-Crissa
Its not.
Sorry, with "rear roof" I mean the whole area from the roof apex to the rear tailgate, including the rear roof glass and the vault cover when closed. The only area left would be the front windscreen (which we need to look out of to drive whilst mobile) , the side windows, frunk and wings.
 

ajdelange

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Are you saying that the pvwatts calculation in the end is incorrect? And so are my numbers?
You can read through their calculation assumptions by clicking the "i" symbols etc.
No. Not at all. Quite the contrary. I pointed out that your result and the numbers I gotwere not inconsistent. I also wanted to point out that weather is quite random and can make a fairly big difference in what panels can harvest. Here's what I've seen in Northern Virginia in the last few months:
NREL McLean.jpg

The red line is a recursive average of MSE hours I received with a smoothing time constant of 7 days. The open circles show the NREL prediction for my region and the solid circles the NREL predictions from the pvwatts program for a much smaller geographical region. Note that what I'm getting is well below the latter data base's predictions. The coarser NREL estimates seem to fit my situation better but note that even so the MSE varied from half an hour above to an hour or more below recently whereas in March they were well below (an hour or more) either of the NREL predictions. That's why I said your estimates were probably a bit optimistic.
 
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damnitjim

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Tesla needs to replace cabin glass roof with solar panels too. There might be enough space in cabin roof to increase energy capture by 50% of what the solar-powered tonneau cover captures.
Agreed. My sunroof cover is always closed anyway so I wouldn’t miss it. Maybe have the sunroof cover be solar panels as well?
 

JBee

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No. Not at all. Quite the contrary. I pointed out that your result and the numbers you had were not inconsistent. I also wanted to point out that weather is quite random and can make a fairly big difference in what panels can harvest. Here's what I've seen in Northern Virginia in the last few months:
NREL McLean.jpg

The red line is a recursive average of MSE hours I received with a smoothing time constant of 7 days. The open circles show the NREL prediction for my region and the solid circles the NREL predictions from the pvwatts program for a much smaller geographical region. Note that what I'm getting is well below the latter data base's predictions. The coarser NREL estimates seem to fit my situation better but note that even so the MSE varied from half an hour above to an hour or more below recently whereas in March they were well below (an hour or more) either of the NREL predictions. That's why I said your estimates were probably a bit optimistic.
Ok so optimistic compared to your specific location in comparison to your local data ;-)

I'd imagine you have some shading as well that would have ro factored in. Obviously, especially low angles will be subject to shading that won't be represented in pvwatts.

So I suppose we can work with those numbers at least to make comparisons between regions.

So one idea I had was to add two axis tracking to improve performance. 1 axis, namely roll, could be acheived by using the air suspension height adjustment feature of the CT to roll the vehicle left and right. (I will be able to work out exact angles on my CT CAD model using the wheel arch and suspension travel dimensionsas guides - but I'd guess about 20degrees).

Then the second option would be a lift system (aka camper pop top roof) with about 35degrees of motion, pivoting on the CT roof apex, and covering the whole rear roof back down to the tailgate.

The third option all depends how you can park, but we can take some liberties there now with 4 wheel steering and about two carparks worth of space for the yaw control, depending on if we want it to "solar summon" where the vehicle would be allowed to drive perodically in a arc to provide the best orientation during the day. Technically if it had enough room it could stay out of the shade in a forrest etc too.

Even though these are fairly limited angles by themselves, in total together with a well placed parking spot to start from, which you could move at least once a day manually otherwise (even without solar summon) you could probably pickup another 20-25% for no to little extra effort or equipment (except the solar camper roof).

Let is know what you think.
 

Ogre

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I don’t think solar charging is great for day-to-day use, because it is so slow. But it might be super interesting for doing multi-day camping trips where you might be pushing the edges of your range. It would be particularly nice because you could use electric accessories without worrying overmuch about eating into range.

FWIW Musk also mentioned solar wings to more than double the size of the charging area. I assume maybe they would be stashed in the Sail Pilar storage when not in use. He said with the wings would give you 30+ miles of range per day which is getting pretty significant.
 

Ogre

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Agreed. My sunroof cover is always closed anyway so I wouldn’t miss it. Maybe have the sunroof cover be solar panels as well?
I don’t think there will be a solar cover, just a big glass panel. Looks very similar to my Model Y which has no cover.
 

ajdelange

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Ok so optimistic compared to your specific location in comparison to your local data ;-)
Yes. Optimistic compared to the real world as represented by places auch as Chicago and Denver.

I'd imagine you have some shading as well that would have ro factored in. Obviously, especially low angles will be subject to shading that won't be represented in pvwatts.
I think pvwatts does allow for some shading.

So I suppose we can work with those numbers at least to make comparisons between regions.
That's where ephemeris based MSE comes in. It tells you how geography comes into it. pvwatts tries to stir in weather too but it can't account for that maple tree or a corner of a dormer. Just using NREL MSE with your estimates of panel and DC/DC converter efficiency will give you the best you can expect with tracking but without particulars of shading from that old gum tree. The numbers for a 2.7m^2 panel aren't that impressive.

So one idea I had was to add two axis tracking to improve performance.
It can't improve performance beyond what my simple method gives you. You would have to improve the weather for that (fewer clouds, less haze).



Let is know what you think.
I guess overall that I think the solar tonneau is a nifty gadget without much practical value.
 

LDRHAWKE

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Being a retired engineer I love all the detail tech talk about solar panel efficiency. I have a different perspective and living in sunny Florida. An added 15 miles a day will get me downtown to dinner/BEER/shop and back; in 0 to 60 at 2.9 sec. I will have limited need to pay to plug into a charger with my CT sitting in the bright sun in front of my place. JUST MAKES ME SMILE THINKING ABOUT😊
 
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John K

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Being a retired engineer I love all the detail tech talk about solar panel efficiency. I have a different perspective and living in sunny Florida. An added 15 miles a day will get me downtown to dinner/BEER/shop and back; in 0 to 60 at 2.9 sec. I will have limited need to pay to plug into a charger with my CT sitting in the bright sun in front of my place. JUST MAKES ME SMILE THINKING ABOUT😊
Florida Man + Apocalyptic vehicle + beer + 0-60 in 2.9 = ?

what could happen?
 

LDRHAWKE

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Florida Man + Apocalyptic vehicle + beer + 0-60 in 2.9 = ?

what could happen?
And the pot calls the kettle black. “Los Angeles has the highest rate of injury-producing and fatal traffic accidents in the United States.”
 

John K

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And the pot calls the kettle black. “Los Angeles has the highest rate of injury-producing and fatal traffic accidents in the United States.”
I have been hit 3 times by cars while riding motorcycles. I used all my Vegas luck from those hits.
Just having fun with inane stereotypes.
 

Crissa

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I don’t think solar charging is great for day-to-day use, because it is so slow. But it might be super interesting for doing multi-day camping trips where you might be pushing the edges of your range. It would be particularly nice because you could use electric accessories without worrying overmuch about eating into range.
It's actually best for day to day use! Instead of losing range every day from sitting around or going to the grocery store, it maintains or stocks away basically free power.

And it's not like you were doing anything with that energy raining down on your truck, right?

-Crissa
 
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