Solar Panel Blown off Roof

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stewartwebr

stewartwebr

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36 years and 16 motorhomes
We were driving back home a few days ago in very high winds, we were on a dual carageway and travelling at speed when there was an almighty crash. I looked to my right to see a huge cattle truck, and assumed the crash came from there.
Other half was not convinced so we pulled into the services about 5 miles further south. We could see nothing untoward with the van so continued the journey. On arriving at the site I noticed the solar panel JB sticking up. Closer inspection revealed on of the 5 160watt solar panel had vanished.
My blood ran cold thinking about what could have happened. We think the panel must have hit the central reservation. On inspection of remaining panels the other one which sits almost parallel to the missing one was also loose to the extent I could pull it off.
The panels were fitted by me 13 months ago using Silkaflex 521. Both surfaces were well cleaned and keyed before fixing. The Silkaflex has parted from the plastic feet as a good amount of approx 6mm high Silkaflex remains on the GRP roof of the van.
The van does tend to “stored” a large amount of water on the roof when sitting on the levelling. I’m wondering if the Silkaflex being submerged has caused it to breakdown, the rear panels are both firmly secured.
I have dropped an email to Silkaflex looking for guidance.
I just cannot believe how lucky we are that we did not hit another car or cause damage to the van. I just hope it did land on the central reservation as lying on a busy dual carageway could have also caused issues.
 
:eek: That’s really scarey! On so many fronts!
 
stewartwebr said:
We were driving back home a few days ago in very high winds, we were on a dual carageway and travelling at speed when there was an almighty crash. I looked to my right to see a huge cattle truck, and assumed the crash came from there.
Other half was not convinced so we pulled into the services about 5 miles further south. We could see nothing untoward with the van so continued the journey. On arriving at the site I noticed the solar panel JB sticking up. Closer inspection revealed on of the 5 160watt solar panel had vanished.
My blood ran cold thinking about what could have happened. We think the panel must have hit the central reservation. On inspection of remaining panels the other one which sits almost parallel to the missing one was also loose to the extent I could pull it off.
The panels were fitted by me 13 months ago using Silkaflex 521. Both surfaces were well cleaned and keyed before fixing. The Silkaflex has parted from the plastic feet as a good amount of approx 6mm high Silkaflex remains on the GRP roof of the van.
The van does tend to “stored” a large amount of water on the roof when sitting on the levelling. I’m wondering if the Silkaflex being submerged has caused it to breakdown, the rear panels are both firmly secured.
I have dropped an email to Silkaflex looking for guidance.
I just cannot believe how lucky we are that we did not hit another car or cause damage to the van. I just hope it did land on the central reservation as lying on a busy dual carageway could have also caused issues.
Click to expand...
Ive talked to Sika tech dept looking for advice on mounting my sheets of Ali to the sides of my van. They will not advise just mounting with Sika alone. They want mechanical fixings to be used at all times. Dont hold your breath waiting for a quick reply. john
 
The gap between mating faces should be about 1mm to 2mm maximum.
6mm is far too much and most likely the cause of failure.
I have no idea why these dimensions should be used.

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pappajohn said:
The gap between mating faces should be about 1mm to 2mm maximum.
6mm is far too much and most likely the cause of failure.
I have no idea why these dimensions should be used.
Click to expand...
Perhaps I have got the depth wrong. They were set at the thickness of a tile plastic gap thing to make sure the depth was correct as recommended by others on here
 
stewartwebr said:
We were driving back home a few days ago in very high winds, we were on a dual carageway and travelling at speed when there was an almighty crash. I looked to my right to see a huge cattle truck, and assumed the crash came from there.
Other half was not convinced so we pulled into the services about 5 miles further south. We could see nothing untoward with the van so continued the journey. On arriving at the site I noticed the solar panel JB sticking up. Closer inspection revealed on of the 5 160watt solar panel had vanished.
My blood ran cold thinking about what could have happened. We think the panel must have hit the central reservation. On inspection of remaining panels the other one which sits almost parallel to the missing one was also loose to the extent I could pull it off.
The panels were fitted by me 13 months ago using Silkaflex 521. Both surfaces were well cleaned and keyed before fixing. The Silkaflex has parted from the plastic feet as a good amount of approx 6mm high Silkaflex remains on the GRP roof of the van.
The van does tend to “stored” a large amount of water on the roof when sitting on the levelling. I’m wondering if the Silkaflex being submerged has caused it to breakdown, the rear panels are both firmly secured.
I have dropped an email to Silkaflex looking for guidance.
I just cannot believe how lucky we are that we did not hit another car or cause damage to the van. I just hope it did land on the central reservation as lying on a busy dual carageway could have also caused issues.
Click to expand...


Not much comfort for yourself but it does reinforce my argument to those that ridiculed me for screwing down as well as bonding with Sikaflex my solar panels mounts and satellite dish.
 
If you mean those plastic cross things for WALL tiles they are around 2mm.
I doubt it was water immersion.

Chemical Resistance
Sikaflex®
-521 UV is resistant to UV
radiation, fresh water, seawater and
proprietary aqueous cleaning
agents; temporarily resistant to
fuels, mineral oils, vegetable and
animal fats and oils; not resistant to
organic acids, concentrated mineral
acids, caustic solutions or solvents.
 
I did 'hide' one of mine behind the roof light and glued a fairing to the front of the other one, specifically to stop the wind getting underneath it. You can just see it on the front panel.There is only a mm or two of Sikaflex under each bracket. I stick my head through the large roof light to clean them and I always check they are still good and stuck. They have been there three years now. They are both 125W panels so pretty big.


DSC02168.JPG
 
I'm afraid I am always sceptical about adhesive only fixing and add physical fixing as well. On the current camper there are wooden reinforcements below the roof surface with 6mm 'T' nuts fitted and stainless bolts through from the panel corner bracket. This would enable me to remove the solar panel without needing access to the inside should I ever need to. Fitting like this is of course easy in a self build being done during the build.

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Isn't 521 just a sealant, not a structural adhesive?
(might have this wrong - going from memory).

EDIT - Just checked. 521 is a sealant and not suitable by itself for solar panels.

This is a screen capture from Sika, but re 221 (another sealant):
Sika 221 Warning.PNG

I used 252 - which is a structural adhesive. Glad no one was hurt of course.
 
Last edited:
Its described as a sealant and this is an extract from their datasheet.

This product is suitable for professional experienced users only. Tests with actual substrates and conditions have to be performed to ensure adhesion and material compatibility
 
I have heard of these plastic corner fixing points loosing adhesion, that's why I used aluminium as recommend by someone on here. Also Sikaflex 512 was the adhesive used.
 
Wissel said:
Isn't 521 just a sealant, not a structural adhesive?
(might have this wrong - going from memory).

EDIT - Just checked. 521 is a sealant and not suitable by itself for solar panels.

This is a screen capture from Sika, but re 221 (another sealant):
View attachment 266893
I used 252 - which is a structural adhesive. Glad no one was hurt of course.
Click to expand...


OP needs to not drive the van until he has taken the other 4 panels off then.
 
Could be a typo and should possibly have been 512.

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Boringfrog said:
that's why I used aluminium as recommend by someone on here.
Click to expand...
What did you use ? Ali angle cut and drilled ?
Did you screw as well.
I'm planning fitting an additional panel over winter and have some of the plastic corner pieces in my basket on eBay.
I think I'll remove them !
 
In my limited experience any plastic to be fixed using Sikaflex adhesive needs to be sanded to a matt finish. Release agents used in the moulding process can remain if the plastic is only cleaned with a solvent. I had a Fiamma aerofoil come loose because I hadn't keyed the surface. The photo of Sika remaining on the roof posted above is classic case of too little adhesive: the whole of the surface of each part to be bonded should be coated before being placed in contact. Squirting it underneath from around the edges isn't enough. I have never used the plastic panel mounts for two reasons: they're over-priced; and it is difficult to remove the panel from them once fitted.
 
Always used small section aluminium angle...then drill maybe 4 holes through the leg that will placed on the roof..this will allow the mastic adhesive to 'bleed' into the holes and therefore enhance the grip.

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Gorse Hill said:
Should be the 252, also important to use the activator/primer to ensure it’s done to spec
https://sikaflexit.wordpress.com/20...ll-a-solar-panel-to-the-roof-of-your-caravan/ (y)
Click to expand...
Seems mixed opinion on which is the right product. Lots of people recommending 512. I read through the attachment, thank you, but note it makes reference to GRP roof and aluminium feet. Anything else you need to call the helpdesk which I shall do today as I have plastic molded feet.

Very interesting link thank you for posting.
 
Think you will always get mixed opinions on what to use adhesive wise but preparation of both surfaces is equally important or maybe more important.

Anyway my plastic solar feet are only stuck on but i cleaned my bits with scotch pad and used IPA to clean the bits certainly a better cleaner than some cleaners ( cleaned roof a little while ago and doesn't appear to be separating between roof and joint ) but everyone to their own and yes safest way would be belt and braces approach
 
Did you only have 4 corner brackets n a 160 watt panel? If so sounds too few to me.
My 100 watt panels are fitted with 6 aluminium brackets and Sikaflex 291i Marine grade & my sat dish with 292i marine grade.

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