Flexible Panels, Mounting Methods and Heat

[Barboots]

I've just realised that the flexible solar panels I bought directly from the manufacturer in China are failing. It appears that they have fractured internal connections between the cells. I can tap certain spots on the panel and restore full output momentarily.

Fortunately some visual defects appeared shortly after installation and I was sent a replacement shipment of their updated ETFE panels, which I've not yet fitted. I was interested to see how the original ones went... plus the task of changing them out didn't appeal because I'd had enough. We have a trip planned in a week or so, therefore I definitely need to get on with the job right now. However I want to avoid a repeat performance (or non-performance actually).

I suspect that the visual defects originally noticed are not the root cause of the problem. This issue was a delamination of the plastic coating from the cells... and whilst this could crack and allow water in, it does not appear to have occurred. Each defect looks much like it did back at installation. There is no discolouration of the affected cells. My current hypothesis of the failure cause is internal fracture due to a different rate of expansion and contraction to the Thermoclear they are adhered to. This is reinforced by the fact that the best performing panel is the one that I only glued the sides of... at temperature it bulges up off the Thermoclear as a result. Yet it hasn't failed.

I'm extremely hesitant to simply glue the new panels down again. I would prefer to use the mounting holes with a "loose" fastener, however the Thermoclear is not removable from the roof without serious work. I'm not up to it. I'm struggling with ideas for getting a robust fix in the Thermoclear to screw/bolt the panels to given I'd need to work from the top. The only one I've come up with is sliding some 100mm long, 9mm wide aluminium or PE stock down the flutes of the Thermoclear and then fixing into that. Essentially a long thin strip of the top surface of the Thermoclear carries the load. Not ideal.

The other option is to use a perimeter frame around the panel, though this edge would assist the build up of crud on the panels... even if it had gaps in it. Panel contamination is a problem already, so I'm not drawn to this idea. Maybe there's a variation someone has invented?

Martin "Dapope" once suggested using longitudinal runs of aluminium sailtrack and sliding the panels into it. I think he even put forward mounting them so the panel was a tiny bit too big, thus creating a very slight domed effect. If not, I dreamt that up. Anyway this general concept appeals the most right now.

All thoughts and suggestions greatly appreciated.

Cheers, Steve

[bagmaker]

something like this?

https://www.rubberonline.com.au/vynalit ... gIfGfD_BwE

glued to roof one side, panel the other.
Should breath OK, should flex enough, thermally and should conform to slight roof curves.
Just a thought

[Barboots]

something like this?

https://www.rubberonline.com.au/vynalit ... gIfGfD_BwE

glued to roof one side, panel the other.
Should breath OK, should flex enough, thermally and should conform to slight roof curves.
Just a thought

Starting over, I'd definitely short-list it. That would have worked well on my lumpy "floating" caravan roof. That said, from where I am now, that would be a lot of going backwards to go forwards.

[Barboots]

Everyone loves a photo.

Note that the effect of tapping to temporarily restore panel output doesn't really correlate to the locations where this delamination has occurred.

Anyway... I'm currently only interested in how to mount the new ones. Once removed these ones can go in the project corner for a rainy day.

[jon_d]

Beautiful installation. I love neat cables.

The flex panels should only be attached in the corners though the eyes. Then they don't tear apart with expansion.

[Barboots]

Beautiful installation. I love neat cables.

The flex panels should only be attached in the corners though the eyes. Then they don't tear apart with expansion.

Thanks Jon.

Yeah there's no way I'm going that way again. Having mulled over it for a few hours, I think I'll router a recess into the Thermoclear and glue in a piece of 5mm thick aluminium with a tapped M6 hole. Once the adhesive has set I'll bolt the panel down using a set screw, washer and Locktite. That way I can leave the panel "perfectly loose", allowing it to expand and contract.

I just can't find a suitable aluminium extrusion to use for the edge-retaining method I wrote of. It's not sufficient to have only 6mm of panel edge held...

That said, until the router comes out I'm open to suggestions [emoji6]

[jon_d]

Why not just lay over the top of the dead panel and use the existing eye as a bolt/mount point?

I think the common way is to glue down squares and mount to the square.

[Dibsy]

That’s a different sort of breakdown a . Looks a bit like the clear coating from the factory didn’t adhere properly . I was looking at some alloy backed one the other day . Guy has had em on his ute for 18 mths look just like new . Riveted to his alloy ute cover Did you do a amp test on the Gamy panel to see if it was putting out much power . I’m going alloy backed ones when we finish this trip as I can save 60 kgs of the roof . Some guys have been fixing there flex panels to core flute type material . It’s a bit heavier than for realestate sale signs . Some have had success some haven’t . I do know a guy he’s got panels went creamy they look like crap .

Dibs

[dapope]

I have two x 100w panels mounted on the front of the curved part of the swagman.
I hooked the leading edges of the panels into sailtracķafter gluing into place with sika.more sailtrack at the rear. I put some sailtrack in the centre of the panels to provide an air gap.
They have been road tested to 130km.
As far as the output goes, they were dodgy from day one, due to poor connections at the panel itself, however, they still appear to contribute to the overall output.
The other panel I have installed is on one of those hardtop windup campers. 4 bolts traight thru the roof with sealing compound, washers and locknuts to allow a little expansion. The panel follows the curve on the roof itself.Roadtested to 120k, it definitely puts out 3.6amps when I last checked in less than good conditions.
None of thses panels have been polished, only hosed occasionally, and the motorhome ones are covered in cocky poo due to where it is parked.
So there you have it..its worked for me so far. Perhaps its the rough enough approach... maybe they are due to fail

[Dibsy]

Hi Martin how how’s goes it we’re in terry’s in front of the shed for Xmas . Anyways I have always wondered how these Flexi panels stand up to wind flap if there not fixe to a solid backing as no one has ever commented it mustn’t be an issue . I just thought it might cause connection failer . That’s a weard breakdown a .

Dibs