Teardrops n Tiny Travel Trailers

For anyone interested in some fairly inexpensive panels, I just picked up two 120W flexible panels from ebay for my Scotty project. They've come down in price, to $119 with free shipping. Mine got here yesterday, and while the packaging wasnt the greatest, the panels look to be fairly good quality. I've bought the Solar Cynergy panels from SolarBLVD before, and have been happy with them. $1/watt for smaller panels is hard to beat!

https://www.ebay.com/itm/120-Watt-120W- ... 1754059260

The panels are shipped with a thin plastic protective film on the surface, which is the discoloration you see in the pictures. It peels right off and leaves a super smooth surface. These are monocrystalline cells.





I'd like to see some examples of how people have mounted these, if you have. I've come across a few on the van forums, but just curious what others have done.

My goal is to have the panels removable (with tools). So I'm thinking of fastening the panels to acrylic sheets, and then fastening the acrylic sheets to some sort of aluminum rails. The rails will be permanently fastened to the roof. I will not be using adhesives to hold the panels directly to the roof. I want the panels to "float" about 1/4" off the roof surface, for airflow. The rails should allow for the addition of another panel down the road.

And don't bother with any comments saying I should have just bought rigid solar panels. I don't want the solar panels to be highly visible and ruin the profile of the Scotty. I understand that they won't be completely invisible, but I want them as low profile as possible.

Lets get creative.

And as a teaser.... here's my current progress on the 1976 Scotty

The exterior will be 100% original, with original skins, original windows, original trim, complete with dents, faded paint, etc. The inside will be completely modern and 'pimped out'.







And the entire album of the whole process is here.... https://www.facebook.com/media/set/?set ... 1bf34c1515

That interior looks great. Can't wait to see the beat-up skins back on it!

And I'm going to watch this thread to see how you decide to install the panels.

T

tony.latham wrote:That interior looks great. Can't wait to see the beat-up skins back on it!

Thanks! Been a lot of hard work... much more than building a teardrop from scratch!

tony.latham wrote:And I'm going to watch this thread to see how you decide to install the panels.

T

Not fair! Thats cheating! You're supposed to come with ideas!

Looks like the top part of the Scotty profile is flat. Is there where you were thinking about mounting the panels? If so, maybe you could use ACM for the panel substrate. For the rails, you could use woodworking t-track mounted to the aluminum roof skin using VHB tape, and then use t-bolts to bolt the ACM/solar panels to the t-track.

T-track is 3/8" tall. Here's a link to one manufacturer. This one is anodized blue, but the are available in a clear/mill finish too by other manufacturers. https://www.amazon.com/gp/product/B075695GSL/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

absolutsnwbrdr wrote:

tony.latham wrote:That interior looks great. Can't wait to see the beat-up skins back on it!

Thanks! Been a lot of hard work... much more than building a teardrop from scratch!

tony.latham wrote:And I'm going to watch this thread to see how you decide to install the panels.

T

Not fair! Thats cheating! You're supposed to come with ideas!

It is bigly fair to stalk other builds on here for ideas...

I want the panels to "float" about 1/4" off the roof surface, for airflow.

How come? I might do another build next winter. If I do, this new 'drop will have a roof-top panel so I'll be following you on this one. I'll be curious to see how you run your wires too.

Tony

tony.latham wrote:

absolutsnwbrdr wrote:

tony.latham wrote:That interior looks great. Can't wait to see the beat-up skins back on it!

Thanks! Been a lot of hard work... much more than building a teardrop from scratch!

tony.latham wrote:And I'm going to watch this thread to see how you decide to install the panels.

T

Not fair! Thats cheating! You're supposed to come with ideas!

It is bigly fair to stalk other builds on here for ideas...

I want the panels to "float" about 1/4" off the roof surface, for airflow.

How come? I might do another build next winter. If I do, this new 'drop will have a roof-top panel so I'll be following you on this one. I'll be curious to see how you run your wires too.

Tony

The airspace is to help ventilate the panels. I can't provide any scientific proof on whether or not it helps, but in theory it should. Solar panels lose efficiency at temperature extremes, so the aluminum sheet roof essentially turns into a big heatsink. As the roof heats up, so would the panels. Any air space provides a thermal gap between the panel and the roof, so theoretically the temperature of the panel should be more stable.

The T track is a great idea.

My concern would be with wind getting underneath the panel while driving. Especially if you're going to mount it to the thin piece of acrylic you could easily break the acrylic at your bolt holes. Are you thinking to mount them crossways on the roof? Then you would need to mount at least the front edge in a few spots to reduce fluttering.

Instead of acrylic you might be better off with some aluminum sheet to mount the panels to. Probably would be stronger and cheaper in the long run.


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I used 3M VHB tape to stick it down on mine. No problems 5 years later and they haven't blown off. The flexible panels do have one characteristic I don't like, the output falls off dramatically at off angles to the sun so the output goes way down in the morning and evening.


Solar Panel Installation Linky, towards the bottom of the thread.

Bruce

KTM_Guy wrote:The T track is a great idea.

My concern would be with wind getting underneath the panel while driving. Especially if you're going to mount it to the thin piece of acrylic you could easily break the acrylic at your bolt holes. Are you thinking to mount them crossways on the roof? Then you would need to mount at least the front edge in a few spots to reduce fluttering.

Instead of acrylic you might be better off with some aluminum sheet to mount the panels to. Probably would be stronger and cheaper in the long run.

Acrylic is very strong, and using multiple attachment points should help. Although now that I think about it, a better alternative to acrylic would be polycarbonate. That stuff can flex without breaking. I was thinking rails would go across, and the panels would run front to back. Probably even have an intermediate support to help prevent the "fluttering".

bdosborn wrote:I used 3M VHB tape to stick it down on mine. No problems 5 years later and they haven't blown off. The flexible panels do have one characteristic I don't like, the output falls off dramatically at off angles to the sun so the output goes way down in the morning and evening.

Solar Panel Installation Linky, towards the bottom of the thread.

Bruce

Thats just too easy Bruce

But ultimately may end up being what I do if I can't come up with a more 'elegant' way to do it with hardware.

Any solar panel at an angle to the sun will have significant drop off, and I've found nothing in research that indicates the flexible panels are any more susceptible to that when compared to a rigid panel. The flexible panels I got are actually supposed to have better performance characteristics than the rigid panels I bought for the X-Cubed 4 years ago. On a flat surface, a flexible panel facing the same orientation as a rigid panel should have comparable output.

The issue with flexible panels (which you shoudn't have on your flat roof) is that if the panel is curved too much,only a portion of the panels gets direct rays, and the curved part away from the sun gets limited rays. That will certainly kill the output. The curve of my roof isn't so much that it should affect it. The panels will have virtually no curve, and face directly up.

absolutsnwbrdr wrote:
The issue with flexible panels (which you shoudn't have on your flat roof)

Why not?


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absolutsnwbrdr wrote:Any solar panel at an angle to the sun will have significant drop off, and I've found nothing in research that indicates the flexible panels are any more susceptible to that when compared to a rigid panel. The flexible panels I got are actually supposed to have better performance characteristics than the rigid panels I bought for the X-Cubed 4 years ago. On a flat surface, a flexible panel facing the same orientation as a rigid panel should have comparable output.

I know, right? I read the same thing about my flexible panels but my meter says differently, the rigid panels easily outperform the flexible ones when they are all flat.

Bruce

sodatrain wrote:

absolutsnwbrdr wrote:
The issue with flexible panels (which you shoudn't have on your flat roof)

Why not?

The roof material acts like a giant heatsink. Which means as the roof heats up, it transfers the heat into the panels. When panels get really hot or really cold, they lose efficiency. On a white roof, its not as big of a deal compared to a bare aluminum or dark colored roof.

bdosborn wrote:

absolutsnwbrdr wrote:Any solar panel at an angle to the sun will have significant drop off, and I've found nothing in research that indicates the flexible panels are any more susceptible to that when compared to a rigid panel. The flexible panels I got are actually supposed to have better performance characteristics than the rigid panels I bought for the X-Cubed 4 years ago. On a flat surface, a flexible panel facing the same orientation as a rigid panel should have comparable output.

I know, right? I read the same thing about my flexible panels but my meter says differently, the rigid panels easily outperform the flexible ones when they are all flat.

Bruce

Hmmm... I'll have to test them and compare the results once it warms back up a bit.

absolutsnwbrdr wrote:

sodatrain wrote:

absolutsnwbrdr wrote:
The issue with flexible panels (which you shoudn't have on your flat roof)

Why not?

The roof material acts like a giant heatsink. Which means as the roof heats up, it transfers the heat into the panels. When panels get really hot or really cold, they lose efficiency. On a white roof, its not as big of a deal compared to a bare aluminum or dark colored roof.

Huh. I suppose that could challenge the AC trying to keep me cool too!


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