Solar Panels taking flight - Disaster

[aandncaravan]

plwsm2000 - 2018-11-26 10:18 PM

 

Great source of information Allan.

 

It looks as though Sika have changed their recommendation of using 252 since this was published back in 2013

[url=] https://sikaflexit.wordpress.com/2013/09/06/how-to-install-a-solar-panel-to-the-roof-of-your-caravan/ [/url]

 

It might be worth mentioning that these adhesives must be applied at ambient temperatures between 10 to 40 degC. 10 degC may be a bit challenging to maintain at this time of year given that it needs several days to cure (a 6mm bead needs at least 5 days!).

I spoke to Sika about this when I fixed my panel, and I was told that it was important to keep the temperature above 10 until at least the adhesive formed a skin. If you are planning to fit a panel at this time of year, it is worth checking the weather forecast!

 

I used 252i (not 252) which has a slightly higher tensile strength than 292i but is less chemical resistant. 252i is quite different to 252.

 

 

plwsm2000, yes you are right the advice has modified

One of the Sika techies was all for using 252 because it is a proper structural adhesive, unlike the 212, 221, 215, 512, etc that often appears in the various Forums 'recommended' advice. But because there already seems to be confusion over the numbering, I felt that 292i sets it apart

 

The techie who really liked 252 didn't realise that some Leisure vehicles are made of GRP and Glass fibre where 292i excels. Being aimed at the Marine environment where these materials are more prolific than anything else it is what you would expect..

 

The aim was to create a simple guide specifying the best product that 'fits all'.

Not always the easiest to achieve, but Sikaflex 292i seems to fit Painted Aluminium roofs, GRP, Fibreglass, Aluminium, higher chemical resistance, etc. and is easy to use.

 

There is also quite a bit of 'crossover' between Marine and Motorhome solar fitting, so the single 'best of breed' product 292i addresses all these aims.

 

The other thing that may have caused confusion is that 252i is way more advanced than 252, and has 3 times less shrinkage. Obviously any sealant that shrinks, potentially opening up gaps for water to get in isn't a good idea on a motorhome roof or boats.

It was also pointed out that 252i is not marketed in this country, but is available from limited overseas sources.

 

Hence all the reasons to go with 292i rather than plain 252.

 

 

One point noted by one Sika technician about 292i's enhanced chemical resistance was it's resistance to Bird droppings (obviously lots of Seagulls in the environment where boars are kept) which wasn't something I had considered before. When you think many Caravans and motorhomes may spend lots of time by the Sea, while not an essential characteristic, it's nice to know it's there to stop the Solar panel detaching later in it's life.

 

It might seem a weird thing to mention, but shows just how many factors there are to consider, like resistance to cleaning chemicals, polishes, substances used in Jetwashes, etc. all outside Sika's control .

Again the enhanced chemical resistance of 292i is worth having.

 

 

One Sika man said that his major issue with plastic brackets, aside from cracking, long term deterioration in the Sun, etc, was that the new ones are rarely fit for purpose.

I am not a plastics expert, so my translation may not be 100% accurate, but apparently when Plastic brackets first appeared years ago they were made in small numbers specifically for the intended purpose. So they were generally designed using materials that worked with the old structural adhesives like 252.

 

But things have changed, as they often do. These brackets are now being produced in large numbers, the best way of which is to include the release agent in with the plastic mix, not as a coating on the mould that has to be regularly renewed.

Obviously a Plastic that is naturally 'slippery' will release from the mould easily and quickly. But that means that because the release agent is actually part of the plastic, no amount of abrading or rubbing is going to remove it. Removing a layer of plastic results in exposing more release agent because it is part of the plastic itself.

 

 

One Sika man had seen a detached panel where he had to investigate a claim made against Sika for supplying unsuitable adhesive when it came off on a motorway causing serious damage and some injuries. That was a huge 270w panel secured with just 4 plastic brackets at the corners. The claimants own insurance wouldn't pay out because the Solar panel had obviously not been fitted 'using common sense practises'.

The claim was not successful, but you can see why these companies have so many disclaimers and are happy to help other companies (like us mugs) 'write the fitting documents for them'.

 

 

It is because it is hard to know what composition the Plastic brackets are made from, or what other materials are mixed that Sika now warn, -

"With many plastic blends it is impossible to give specific guidance due to the potential variety of components and internal/external release agents they contain. Thermoplastics are subject to a risk of stress cracking".

 

 

When I started this I thought it would be straight forward, I can't believe the extra information that has been sent by Sika for us to include from preparation to temperature, and curing time to disclaimers, etc.

Much of the information in the data sheets, all in one place.

 

Nor did I expect the number of emails from professional installers defending what is now clearly exposed as inadequate practice for many .

 

I guess those traders that have used unsuitable plastic brackets may now be facing unhappy customers and/or Law Suits and they don't want us pointing out it's time for a rethink.

We are not popular right now in the trade. But have we ever cared about that, regularly taking on things we see as inappropriate?

 

 

The thing that has surprised me the most is that the MotorhomeFun forum, where this thread started, has blocked attempts to publise the new web page guide on fitting Solar panels.

 

Obviously that has been done in the interests of it's paying members and nothing to do with protecting the Solar panel fitting traders who advertise on there.

 

Therefore can we ask that you make a point of reading the fitting page, and if you feel it is appropriate to publicise it?

As stated above the web page should be fully up to date by Wednesday evening.

 

 

[Rayjsj]

colin - 2018-11-18 8:19 PM

 

I've seen many a post recommending just sticking down with Silkaflex, I'm not a fan of this method and glue and screw.

Sikaflex 512 IS a glue ! And anything that avoids drilliling a hole in the roof has my vote.

 

As an aside, I fitted a Fiamma roof deflector on my daughters Volkswagen camper, to allow her to leave her roof vent open during travel. I used ONLY Sikaflex 512 white, it had only just come onto the market, about 8 or 9 years ago.....yes its still in place...and still stuck firmly to the roof.

Not that technical, but roof is fibreglass and deflector is ? ABS ? Whatever, its still stuck very firmly.

[Derek Uzzell]

Given the light weight and relatively large ‘footprint’ of a roof-mounted wind deflector, if double-sided carpet tape had be used to attach the deflector to your daughter’s VW camper, there’s a good chance the deflector would still be stuck firmly to the camper’s roof today. It’s not a valid comparison where solar panels are concerned...

[monique.hubrechtsgm]

When the atmospheric pressure drops we going to fall by gravity. Galilee Galileo. Airborne birds and planes.

[Robbo]

aandncaravan - 2018-11-27 11:42 AM

 

The thing that has surprised me the most is that the MotorhomeFun forum, where this thread started, has blocked attempts to publise the new web page guide on fitting Solar panels.

 

 

Allan, I was horrified to hear this, being a MHFun member myself. Are you sure you're still a fully paid up member and therefore able to post ? Most MHFun members would be very appreciative to have a link to your new web page on solar panels.

 

Once your latest version of the webpage is complete, I'd be happy to spread the word :-D

[aandncaravan]

Robbo, No I am not a paid up member, I was banned some time ago after I published the real workings of a Vanbitz Battery Master device as opposed to the Traders claims.

I suggested that a motorhome specific dual battery solar regulator would be much more efficient than Victron regulator + a £59 (as the price was then) Battery Master.

 

I understand Jim also sells the Battery Master product.

 

My access stopped and despite emails to Jim, it was never reactivated.

 

 

Whenever I was able to give any advice to help someone on the MHF forum, I would pester Lenny who, to his great credit, never complained about me being a nuisance.

 

 

I eventually got someone to agree to create an account for me and post messages on my behalf, and I paid their subs this October, so they are paid up with about 11 months to run on the membership.

 

When comments were made on my behalf on the thread about Solar panels detaching from motorhome roofs here : ..https://www.motorhomefun.co.uk/forum/threads/solar-panel-blown-off-roof.186806/page-9

Eddie of Vanbitz made a scathing attack and Jim supported it.

 

It wasn't nice and eventually Someone made a post saying they were disappointed with Eddie and Jim, saying -

"I do find this discussion a bit of a sad discussion most people on here give advice free from any gain to their own ends,

If any one makes a statement of 'I am correct', I am sure they will be able to back it up with credentials ie many years in electronics or electrical engineering to back up any statements.

Most on here know a basic amount, some know a vast amount, some profess to know it all, but all of this info is free and in the best of intention.

I find it a real shame that two well respected traders have to air their grievances on here".

 

 

There were some nice comments made and a response to these were made on my behalf but it doesn't show up in the audit trail.

Although the poster can see it, it appears no one else can. The Audit shows SteveandDenise as the last posters.

 

The thread was then closed, by Jim. It seems he didn't want anyone to see the last post on my behalf or risk anyone else making comments.

 

 

A few days later a brand New post was made on my behalf about fitting Solar panels and the work with Sika, called - "Fitting-of-solar-panels" In the Solar section.

but it seems no one can see it.

I can't for example, but the 'Poster' can.

 

The person who was posting for me had no notification about being blocked. No warnings, nothing.

 

 

I would be interested if you can see the new posting, or the last message in the 'Solar panel blown off roof' that was posted on my behalf.

 

 

[Robbo]

Hi Allan

 

The thread "Solar panel blown off roof" was closed after the post by SteveandDenise, post #169 on 20th Nov.

 

No sign of the later thread started by the other person you refer to. It's all a great shame but probably best to ignore it all, if you can. The last thing you need at the moment is additional stress.

 

 

[Paul-]

I've been in contact with a friend who has contacts in the plastic manufacturing industry I asked about silicon being added to the plastic in the manufacturing of the solar panel mounting brackets (feet) and they've not heard of it 

 

Could the chap from Sika offer any links please. 

[aandncaravan]

Robbo, thank you, appreciated.

 

 

We are still waiting for some minor info from Sika, but everything we can currently put on the web page is in place for most types of Motorhome roof that are considered suitable - GRP, Glass fibre, painted Steel and painted Aluminium.

All materials that Sika 292i works really well with.

 

Sika have suggested a thicker bead than we previously published, so that has been included.

 

The Sika details on preparation have been added. While it now contains Sika's extra request to cover temperature and curing times, etc, we are waiting for some minor details on other questions raised, that few of the videos and guides out there even mention.

 

For example, one thing that has come through this morning is about 'protective' paint finishes that are sometimes used.

Paintseal says it uses a "PTFE (teflon) based exterior/Interior protective coating" which might not be the best base for an Adhesive.

Others like Supagard, PaintX, etc may also provide a super slippery finish?

 

The Initial response from Sika was that 208 remover/cleaner should clean everything from the roof surface, including these super tough protective coatings, but the techy said he would confirm that and get back to us.

 

I am sure there will be other changes, we are getting so many emails from so many sources, that some of it will have to be added later.

 

So if anyone is interested, it is ready to be 'spread about'.

 

Still getting emails defending Plastic brackets, mostly trade, but just ignoring them, they are not listening to what Sika say and I don't think that will change, so no point responding.

 

 

One eagle eyed browser reading the Solar Pages has spotted the new battery competition web page on our site and asked what it's all about.

Alpha batteries want to say thank you for the support and fantastic feedback, so are giving a Yuasa L36-EFB battery away free in a competition to the members on this forum.

More than that I can not say just yet, but watch the web page.

 

[Brian Kirby]

A personal view. I would not rely on bonded fixings alone.

 

All adhesives/sealants degrade over time. Many (most, I believe) coachbuilt roofs are of thin sheet material that is not itself bonded rigidly to its substrate, so is prone to some movement. All roofs are prone to hold water, even if only when it is actually raining, and in winter that water will infiltrate any gap between adhesive and roof, and then freeze and expand, so enlarging the gap and reducing the contact area of the adhesive. On painted aluminium (coachbuilt) or steel (PVC) roofs, what you are sticking to is a film of (probably weathered) paint, so the ultimate bond strength depends on the adhesion of the paint film, which is a variable unknown.

 

On a vehicle roof, the actual wind speed affecting the panels will at times be substantially in excess of road speed (e.g. when driving into a headwind), so may well exceed 100MPH (well in excess of hurricane force). The position of the panel relative to the airstream over the roof will influence how much uplift is experienced which, I would suggest, is also an unknown.

 

Applied under ideal circumstances, the adhesives are very good, but the consequences of a detached solar panel on a busy road are potentially catastrophic. It is not the small chance of the panel detaching that should be contemplated, but the potential severity of the accident that might follow (for example were it to fly into the windscreen of a following coach).

 

Personally, I would put one mechanical fixing (the belt) into the roof of a PVC, at each fixing point, in addition to the adhesive (the braces). The adhesive will adequately seal the fixing hole and, by slightly tightening the mechanical fixing after the sealant has cured, it will be under compression, so giving it a secondary role as a sealing gasket should some adhesion be lost.

 

On a coachbuilt, I would favour mounting the solar panel/s on roof bars that are themselves mechanically fixed. If roof bars are not present, I would say fit them.

[pepe63xnotuse]

I'm inclined to agree Brian.

Properly attached *roofbars (*or similar), would be my preferred option.That method, would also give a large margin of tolerance for if/when panels needed to be renewed/upgraded.

 

Irrespective of whatever materials they are made of, bonding on one-piece mounting brackets, that are positioned specifically to fit the panel that is being installed at that time, seems somewhat short sighted. As I said on page one, I think it's far better to have an adaptable/versatile two-part mounting bracket approach for such things.

[Derek Uzzell]

As many motorhome converters nowadays offer a solar-panel system either as standard or as a factory-fitted option, it might be worth exploring what methods they use to attach the panels.

 

Of course obtaining that sort f information might not be easy...

[aandncaravan]

Derek, I am hoping to soon see a Hymer, less than a year old, that is on it's third panel, fitted a few weeks ago. It originally had a flexi Solar panel fitted new, which never worked properly from the start.

The Dealer eventually put their hands up and fitted a second flexi panel about 3 months ago. Again it worked, but not properly.

It was fitted badly with four screws at each corner (yes on a flexi panel) and without any load spreading of the screw heads. Screws so tight the panel was distorted, and probably the reason for the partial failure.

 

The Dealer has now fitted a third 'Solid' Solar panel which I will report back on when I see it in a few weeks.

All this is on a new, expensive recent purchase Motorhome from a big Dealer, who one would expect to know their trade.

 

 

We have not seen a professionally fitted Plastic bracket Solar Panel with any spacers or an Adhesive bead anywhere near 5mm. Your can just look at the side of the feet to see the bead thickness.

So however they do it, there isn't enough bead to ensure expansion over several years and long term attachment. It might last a few summers, but the long term prognosis isn't great.

 

 

If you look at this 'prefessional' fitting video :

it breaks all common sense rules.

They don't even clean the roof, let alone degrease it or abrade it.

If you look at the section where the Plastic brackets are fitted to the Panel (remember these are brackets prone to long term stress cracking) and you will see small headed screws with little surface area tying the panel to the plastic feet. When cracking and weakening occurs in 5 + years time, that is going to be a disaster point. Surely the most basic of common sense with plastic would be to use washers to spread the stress of the screw head?

 

Watch as he puts on a really, really thin bead of Sealant onto a really shiny slippery plastic bracket, it is horrifying. No abrading or preparation of the Plastic at all.

But he then places the whole panel onto the dirty roof and squashes it down so hard, that what little adhesive that might have been in there is squeezed flat.

 

There is no advice on preparation at all. Not even the smallest mention of it's absolutely key and critical importance. Totally bonkers.

 

 

I think that basic process was used on all the professional panels we have seen, because they all have ultra thin beads of adhesive. .

 

 

So I agree with you about finding out how it is done by the trade, it will be very interesting.

 

Maybe create a survey asking those with professional fitted panels to measure the Sealant gap and also look for evidence of spacers.That is an easy to check guide of the fitting quality.

 

Ideally ask everyone to contact their fitters and ask them what adhesive, cleaner, etc fitting techniques they use and put that into the survey?

 

 

I think I have now done enough on this, let someone else set up the survey and take all the the Flak I have had the last week.

 

[globebuster]

aandncaravan - 2018-11-30 1:48 PM

 

Derek, I am hoping to soon see a Hymer, less than a year old, that is on it's third panel, fitted a few weeks ago. It originally had a flexi Solar panel fitted new, which never worked properly from the start.

The Dealer eventually put their hands up and fitted a second flexi panel about 3 months ago. Again it worked, but not properly.

It was fitted badly with four screws at each corner (yes on a flexi panel) and without any load spreading of the screw heads. Screws so tight the panel was distorted, and probably the reason for the partial failure.

 

The Dealer has now fitted a third 'Solid' Solar panel which I will report back on when I see it in a few weeks.

All this is on a new, expensive recent purchase Motorhome from a big Dealer, who one would expect to know their trade.

 

 

We have not seen a professionally fitted Plastic bracket Solar Panel with any spacers or an Adhesive bead anywhere near 5mm. Your can just look at the side of the feet to see the bead thickness.

So however they do it, there isn't enough bead to ensure expansion over several years and long term attachment. It might last a few summers, but the long term prognosis isn't great.

 

 

If you look at this 'prefessional' fitting video :

it breaks all common sense rules.

They don't even clean the roof, let alone degrease it or abrade it.

If you look at the section where the Plastic brackets are fitted to the Panel (remember these are brackets prone to long term stress cracking) and you will see small headed screws with little surface area tying the panel to the plastic feet. When cracking and weakening occurs in 5 + years time, that is going to be a disaster point. Surely the most basic of common sense with plastic would be to use washers to spread the stress of the screw head?

 

Watch as he puts on a really, really thin bead of Sealant onto a really shiny slippery plastic bracket, it is horrifying. No abrading or preparation of the Plastic at all.

But he then places the whole panel onto the dirty roof and squashes it down so hard, that what little adhesive that might have been in there is squeezed flat.

 

There is no advice on preparation at all. Not even the smallest mention of it's absolutely key and critical importance. Totally bonkers.

 

 

I think that basic process was used on all the professional panels we have seen, because they all have ultra thin beads of adhesive. .

 

 

So I agree with you about finding out how it is done by the trade, it will be very interesting.

 

Maybe create a survey asking those with professional fitted panels to measure the Sealant gap and also look for evidence of spacers.That is an easy to check guide of the fitting quality.

 

Ideally ask everyone to contact their fitters and ask them what adhesive, cleaner, etc fitting techniques they use and put that into the survey?

 

 

I think I have now done enough on this, let someone else set up the survey and take all the the Flak I have had the last week.

 

 

That video certainly is a lesson in how NOT to install a solar panel, and those feet look really poor quality.

[Paul-]

Thanks for the link its made my day, I didn't realise people could be so silly or cut so many corners on work or parts, as for those cheap and nasty brackets, if he paid more than £2 a set he's been robbed.

The scariest thing is that he's talking confidently as though he knows what he's doing and someone could possibly copy him :-(

[spirou]

After all this talk about panels taking off I decided to check on ours... nothing moves :-D But here are two photos of our install. I feel the window in front and the AC etc. behind it are more than enough wind deflection/turbulence creators that there's never much lifting force generated. Plus, the panel is fastened with locking nuts so not likely to come apart anyway.

 

[weldted]

Having been advised to connect my solar panels in series to increase voltage I had to remove two of the panels to get at the wiring (the other two are hinged. The brackets were installed in 2012 using Slikaflex 252i and one securing screw in each foot. It took close on two hours with cheese wire and a heat gun to remove the four feet. On the original mounting the footprint was abraded through to the alloy skin etched both the roof and the foot. No sign of decay of the adhesive was found. The fixing screws are required in my opinion as the Elddis has a floating skin of aluminium on the roof and is not bonded to the structure underneath.

[mark569]

Rayjsj,

 

512 is not a glue, it is a sealant. https://hkg.sika.com/en/Solutions%20Products/document_download/PDS_Sikaflex.html

 

Solar panels are heavy.

252i is a structural adhesive, much stronger.

peoples lives are at stake if it comes of the roof!