Adhesive for solar panels

[Marc_H]

I'm about to install some flexible solar panels on the roof of our Lagoon catamaran. I was thinking of using Sikaflex 291 or 3M 4200. White silicone even crossed my mind.

I know that I will have to remove them later at some point due to failure, upgrade, etc. What adhesive would you guys recommend that would adhere them well enough yet not so tenacious that is would be very difficult to remove? The area that they will be attached too is non skid gel coat.

Thanks in advance.

Marc

[Pete7]

If they are semi flexible panels, since they don't weigh much I use velcro blobs to secure it to the hatch infront of the spray hood. Been there two years without problem.

https://www.screwfix.com/p/velcro-br...FdONGwodNioHOQ

If you use sikaflex then eventually removing the panels and remaining sika is going to be a nightmare.

[john61ct]

I would attach permanent mounting for an underlying Sunbrella or similar,

ideally completely taut so no flex at all in use

then zippers all round to make the panels easily removable.

[cwsymons]

I would suggest not directly sticking them to the coach house roof. I read recently that sticking flexible solar panels directly to the roof adversely affected the output due to heat buildup (It was quite a significant drop). Lifting them off slightly would allow air flow underneath thereby by reducing the heat buildup.

You could try putting down small flexible battens that run fore aft then sticking them to those.

My 2c worth.

[KWISPEL]

If you glue them wit a strip Sika on the side, you can remove the Sica later if you use Acetone combined with a plastic scraper and a cloth. Not a big deal and nicer than gelcoat repairs.

[Emerald Sea]

Yes, better over your sunbrella. Flexible panels over your gel coat are going to destroy, or at least permanently discolor, the underlying coating. You can fry an egg on these panels in the tropical sun and the underlying gel coat, over time, just bakes up. Beware.

[Emouchet]

Make sure air can flow under the panel. Those panel to keep performing at 100% must be kept cool. When solar panel heats up, their efficiency drops significantly.

[Eder]

My 4- 100 w flexibles are attached to my sunbrella bimini top with snaps installed at the panel grommet locations and 2" velcro sewn to the sunbrella....self stick to the panel...3rd season like this.

[john61ct]

Originally Posted by Emouchet

must be kept cool. When solar panel heats up, their efficiency drops significantly.

And their lifespan shortens (even more)

[mikedefieslife]

Originally Posted by Emouchet

Make sure air can flow under the panel. Those panel to keep performing at 100% must be kept cool. When solar panel heats up, their efficiency drops significantly.

I'd be interested to see some stats on temperatures of semi flexible panels with air flow underneath.

All the newer ones are mounted to a few mm of fibreglass (a terrible conductor). I would imagine air over the panel is going to be an awful lot more effective.

In fact. I've never seen a semi flexible panel mounted on a solid surface such as a hardtop, coach roof, or deck, that has airflow underneath it.

[robert sailor]

Originally Posted by Emerald Sea

Yes, better over your sunbrella. Flexible panels over your gel coat are going to destroy, or at least permanently discolor, the underlying coating. You can fry an egg on these panels in the tropical sun and the underlying gel coat, over time, just bakes up. Beware.

This person is properly informed, after a few years your gelcoat will turn a light brown and start to crack like corn flakes after being absolutely cooked by the high heat of the panel never install panels direct to any gelcoat surface you don't want to destroy over time.

[3Days_at_a_time]

My recommendation is to use 3m VHB adhesive tape. You can get it in various thicknesses so that you can leave an air gap under the panels, as well as provide a path for moisture to get out. It is what I have done and I have not had problems even in florida's summer heat. It is clean and easy. It also hold well. I tow my boat so the panels have see 65-75mph wind for hours at a time.

[mikedefieslife]

Of course to protect the gelcoat you'll want some kind of backing. Foam board is popular.

VHB works well. The best thing about it, is that it will stick well to a textured grp surface, and although difficult to remove (from a textured surface) it's nowhere near the dove-**** that sika is.

Another option for nice flat smooth surfaces is the tape used in repairing leaking roofs. RVs use it and happily do 60mph on the highway without issue, so it's childs play for the type of winds and weather a boat encounters.

The ultimate though (in price if nothing else) is 400 head per cm2 3M dual lock. It has a good adhesive backing, and the locking mechanism is a lot stronger than velcro. Problem is that for a lot of it the cost will be more than your panels.

[john61ct]

Your backing should be a heat sink, ideally gapped between it and the panel. Usually aluminum.

Insulation between that backing and the heat sink to protect gel coat maybe, but trapping the panel's heat worsens the problem.

The framed panels end up being **lots** cheaper over time.

[rabbi]

Originally Posted by john61ct

The framed panels end up being **lots** cheaper over time.

+1
I have yet to see flexible walk-on panels that are actually still producing anywhere near the rated output after someone walked on them several times a day over a period of years.

On the other hand I have seen plenty of flexible panels that had an output of close to 0W after a few years passed.