Solar Panel Installation Failures

[Danjo]

Here’s a thread to post all the solar panel installation failures.

When you post, please comment on the cause

This one appears to have failed because the sheet metal screws connecting the bracket to the roof tore out.

https://m.youtube.com/watch?v=ZERE9T5vol0

[Danjo]

This one doesn’t discuss the reason for the failure, but in the slo-mo footage at the end, it appears that the brackets tore out of the roof. Likely a sheet metal screw installation. YouTube comments seem it indicate adhesive mounting

https://youtu.be/-X8BF8HrhaI

Here’s a screenshot of the panel. It looks like adhesive failure

[HamSkoolie]

Not surprised at all by the first. Older Class B and he doesn't sound like the kind of guy that does inspections on the roof......hell @2:150 or so he's explaining that its the front panel but he doesn't know if it took anything else out...... indicating he didn't even go up and look!!!!!! @2:30 he verifies that.
To me that's unfathomable and puts this guy in the category of "what not to do".
I'm going to go out on a big fat limb and guess that those brackets were self tap screwed to the fiberglass roof when those big aluminum pieces were right there for at least a couple of brackets and "through the entire roof with bolts" was the correct way to mount those panels.


On the second vid, it could be roof failure but it could also be that the brackets were only bonded to the roof. You hate to think someone would rely on just an adhesive but you just never know.

That was a commercially built fiver and if they're anything like the US models they've gone to such thin materials on the roof that you have to use a wide board to distribute the weight when going up every 90 dyas for roof warrant "sealant maintenance".

[Zork]

Hmm. No wind deflector, which means the panel is essentially a piece of metal flapping in the air, wanting to depart as soon as possible. Even cheap chinese roof racks have wind deflectors.

On top of that, sheet metal screws!!!??? I don't suppose he ever heard of pop rivets, dipped in sealant before securing them to the roof through the bracket, to keep moisture out? I've built wet wing fuel tanks with pop rivets dipped in Pro-Seal. NOTHING gets out of that, even with the wing flexing in the airflow for years.

[Rwnielsen]

I plan to bolt down some unistrut with 1/8" steel backing plates bedded in construction adhesive on the inside. Same way I mounted my 'Camper Bob' ladder on the back.
I don't think people realize how much lift a solar panel can generate at speed. I would imagine several hundred pounds.

[Zork]

Originally Posted by Rwnielsen

I plan to bolt down some unistrut with 1/8" steel backing plates bedded in construction adhesive on the inside. Same way I mounted my 'Camper Bob' ladder on the back.
I don't think people realize how much lift a solar panel can generate at speed. I would imagine several hundred pounds.

You would be surprised how much research has been done into flat plate airfoils.

http://brennen.caltech.edu/fluidbook...ateairfoil.pdf

Resources | Aerodynamics for Students

https://www.google.com/search?q=flat...hrome&ie=UTF-8

The bottom line is that even a very small angle of attack (meaning the panel is not EXACTLY aligned to the airfoil over the roof) which yield a significant amount of lift. The wind deflector (when placed correctly...) does not allow any significant airflow under the plate and kills the lift.

[HamSkoolie]

Originally Posted by Rwnielsen

I plan to bolt down some unistrut with 1/8" steel backing plates bedded in construction adhesive on the inside. Same way I mounted my 'Camper Bob' ladder on the back.
I don't think people realize how much lift a solar panel can generate at speed. I would imagine several hundred pounds.

Just put your HAND out the window at 55 mph and impart some AOA..... now multiply that force to that of a plate the size of a panel!!!!!
Yep....it's a LOT

[Zork]

Originally Posted by HamSkoolie

Just put your HAND out the window at 55 mph and impart some AOA..... now multiply that force to that of a plate the size of a panel!!!!! Yep....it's a LOT

Even the dogs know that!

[Rwnielsen]

Originally Posted by HamSkoolie

Just put your HAND out the window at 55 mph and impart some AOA..... now multiply that force to that of a plate the size of a panel!!!!!
Yep....it's a LOT

I used to do that as a kid, I'm 67 now and still do it?...all the time.

[Oldyeller]

I'm late to the discussion but thought I'd add that the RV in the first video is a Chinook and I believe the RV body on those is fiberglass and likely not overly thick. You can see from the end of the video that the owner used screws to attach the panels, series of bad choices.

It looks like there are 2 cross rails on his roof used to mount the cargo carrier. The owner decided to cut those down and ignore them and mount his solar panels to the fiberglass of the roof with small screws, go figure. Seeing stuff like this is good for me as it helps me compare my thought process on mounting solar panels to other folks, I find I'm really paranoid about the attachment of my solar panels

[Oscar1]

Back in April there was a rather heated debate here regarding the use of tape to bond solar panels to a roof freshly painted with Tropicol. A bad idea in my opinion but apparently one that seems to be used in the rv world too often with tragic results.

[Danjo]

Originally Posted by Oscar1

Back in April there was a rather heated debate here regarding the use of tape to bond solar panels to a roof freshly painted with Tropicol. A bad idea in my opinion but apparently one that seems to be used in the rv world too often with tragic results. ]

Just a small 100W panel catching the sail just right at 60MPH could decapitate someone. The idea of sticking them up there with tape is irresponsible. Aside from having questionable bond strength, when the tape fails it’s going to fail catastrophically. At least with bolts theres some chance when you hear that panel rattling before it makes it’s way loose

[Oldyeller]

Originally Posted by Rwnielsen

I plan to bolt down some unistrut with 1/8" steel backing plates bedded in construction adhesive on the inside. Same way I mounted my 'Camper Bob' ladder on the back.
I don't think people realize how much lift a solar panel can generate at speed. I would imagine several hundred pounds.

I used the struts you get at Home Despot and I bolted through the flange of the ribs and overlapped roof panels at the intersections with washer backing and nyloc nuts. I went through 4 layers of sheet metal with each bolt.

[Danjo]

Originally Posted by Oldyeller

I used the struts you get at Home Despot and I bolted through the flange of the ribs and overlapped roof panels at the intersections with washer backing and nyloc nuts. I went through 4 layers of sheet metal with each bolt.

Right, like that!

[Oldyeller]

Originally Posted by Danjo

Right, like that!

I'm still paranoid about it. My first panel will be over 3 feet behind the leading edge of the front of the roof. I could have gotten another panel in front of it with just a few inches hanging over the roof's leading edge but I quickly decided against that. Each of my panels is 40x80" and weighs about 40 pounds, too big to take chances with. I suspect I'll be checking those panels at every stop for quite a while if/when I finally get on the road.

[flattracker]

I will be using flexible panels that are screwed down to the roof. I will be installing stainless rivnuts through the roof, stainless button head bolts and sealing all with silicon caulk. Between the roof and the panels will be .2" uluminized insulation. with the silicon caulk I don't expect any aerodynamic issues. Since the panels will be mounted along the centerline of the roof, they won't be too obvious going down the road. I will be using small enclosures with gland fittings where the wires go through the roof.
I will be inspecting my panels periodically also.


The insulation will keep the bus cooler inside and the panels cooler also.


I know from experience that solar panels can get pretty warm. I have one that I use to keep the tractor batteries charged and it can reach 80 degrees in late October here.

[Rucker]

Great thread. I've searched for VHB failures - I'm still not convinced straight up VHB tape doesn't work. Lot's of opinions, but for those who HAVE used only VHB I have not yet found one report of failure. Doesn't mean it won't fail, just no one saying 'hey I tried this and it failed.'

Success stories with VHB tape:
https://faroutride.com/solar-panels-installation/
(five years and counting)

https://www.campervantraveler.com/ta...anels-to-roof/
Two years

Here's a great thread with pros and cons-very strong anti-VHB, but at the end of the day all theoretical-based on calculations and assumptions. Those with experience using JUST VHB continue to report no issues.
https://sprinter-source.com/forums/i...threads/57437/

Anyone here able to report a VHB failure?

[Oscar1]

I found this communication with 3M on a Sprinter site.

I noticed the 3M rep says that the tape is not even recommended for this type of installation but if you are going to use the tape, use in conjunction with mechanical fasteners. He even says mechanical fasteners twice. (So why even use the tape)
Best part is the OP questioning if that is just a "cover your ass" response.
I can just imagine that thought process, "ya I know 3M spends millions on research and development but I think I know more about their product than they do so I'm going to go ahead and do it anyway, I'm sure it won't come off and kill anyone"

[Oldyeller]

I'm no expert, I don't even have much experience using adhesive/mounting tapes in the automotive world but I've seen some videos in which people use some type of adhesive to attach solar panels. The thought I had about it is the adhesive acts on the surface layer of the materials. The attachment is only as strong as the surface layer, in most cases in our world, paint. Most of the buses we get hold of are 10 to 15 years old (guesstimate), I have no confidence in the integrity of the paint on any of our buses, especially after being in contact with whatever kind of chemical agent present in the adhesive.

When I was shortening my bus last year I considered using 3M panel bond during the reassembly. I down loaded the instruction PDF and read it. I concluded that, in my situation, I didn't have the confidence that I could meet the requirements 3M listed to create a good bond. I think the same thing when considering using some sort of adhesive bond to attach solar panels. I'm just not going to bet somebody else's life that I got it right.

[HamSkoolie]

I used that tape to adhere four tinted window "fairings" on my 1992 (back in 92/93) GMC Dually. While I didn't lose any of those fairings, one of them did indeed come loose on the trailing edge.
As has been said, it's only attaching to the paint.
No way in heck I'm going with just tape for something like a solar panel. And OMG they only put it on the bottoms of the brackets!!!!!! When I first started reading I thought maybe they'd put it along the entire length of the panel frame and had some decent adhesive area.
YIKES