diy solar

diy solar

Fatal accident caused by loose panel on road

I Second this.



Mind giving a little detail into construction. I'm guessing it's 1/8 inch steel line with the ends self crimped. I would like to know what you did with the two ends of the wire, and what they are attached to. My guess is its around an antenna mount you can raise.

Not many tether-worthy points on the top of most RVs.
This is "49 Strand Stainless Steel Black Vinyl Coated Cable" from Amazon. Just found the nearest sturdy thing which looked like the TV antenna. On another trailer I ran the cable around the air conditioner. Each 100W panel has 8 screws holding it on and I inspect them every trip. I seriously can't imagine all 8 screws giving up the ghost so this is really just extra peace of mind.
 
On another trailer I ran the cable around the air conditioner.
I think both of my air conditioners would be the only place on my RV roof I'd consider mounting a tether to. Just have to figure a way that the cable loop would not slip off it. I would not use the digital TV antenna I have on my RV for a secure point.

I will be checking the Panels with each drive myself.
 
The cops should start checking all RVs and arresting anyone who glues panels on the roof. Better check the wheels too. They might be glued on.
Use the right "glue" and apply to clean surfaces has worked for me for years. If the glue has a large surface area it will be far stronger than any screw in timber or light aluminium.

I use Sikaflex 252 and either large plastic moulded brackets or right angle alumininium brackets the entire length of solar panel, not short little brackets with no surface area.
 
Use the right "glue" and apply to clean surfaces has worked for me for years. If the glue has a large surface area it will be far stronger than any screw in timber or light aluminium.

I use Sikaflex 252 and either large plastic moulded brackets or right angle alumininium brackets the entire length of solar panel, not short little brackets with no surface area.
Anything dangerous needs to be fool proof. Do you realize you might be encouraging a fool to glue panels to his roof? A couple screws or a tether could have saved lives.
 
Traditional panels that use mounting brackets that are glued to the EPDM roof are an accident waiting to happen. Most of the time, we're not talking about this situation. It would be an outlier. While I would like to say that nobody is that stupid, that's why we have the Darwin Awards.

A flexible panel that is glued to EPDM, sealing all four sides to prevent any possible lift from winds, is not likely to be a problem. But it depends on the quality of adhesive and the installation technique used.

I continue to be skeptical of any traditional panel held to any type of roof with just tape or glue.

It would be interesting to go to the RV graveyard and install panels on different roofs, using different techniques, to see how much force each method can handle.
 
The cops should start checking all RVs and arresting anyone who glues panels on the roof. Better check the wheels too. They might be glued on.


Anything dangerous needs to be fool proof. Do you realize you might be encouraging a fool to glue panels to his roof? A couple screws or a tether could have saved lives.

Are you being serious?
 
VHB is a structural adhesive. If properly done on a suitable substrate, VHB will take way more to pull a panel off a roof than screws. The operative portion is...

"PROPERLY DONE"

Bond to a shit surface, get a shit bond (e.g., peeling/flaking paint).
Fail to properly clean and prep both surfaces, get a shit bond.
Get a great bond to something between the tape and primary structure that has a poor bond, get a net shit bond.

Airplanes have been made with bonded skins - not a single rivet holding the skin to the ribs. I've flown in several.


I've personally owned one with bonded leading edges forward of the main spar - no rivets on the portion that takes the wind loads.

Many modern composite aircraft that are just glue impregnated fiberglass, carbon fiber and kevlar. Not a single rivet.

When properly engineered and executed, an adhesive bond will be superior to a threaded fastener in this application. Does it hurt to run a screw through it or use a tether for "feel good" factor? Nope.
 
It seems bolting down the panels is the only safe way from reading through all the comments so far.
Those advocating a tether have no faith in the glue and the tethers themselves look suspect just by the samples shown.
A longer bolt will solve any problems!!
 
My thoughts when seeing some of the suggested tether wires was, how long would it take for the wire to saw (or straight rip) through the soft aluminium of the panel frame should the panel break free, and would the driver, especially if caravan (trailer), even notice that there was a panel flapping round on the top of the van in that time frame.
 
I am. I didn't say it can't be done safely. You can't be serious comparing aircraft builders to DIY'rs. lol

I just couldn't establish if you're mocking the nanny state or embracing it. The latter it is. People really should be arrested for not screwing down their panels, and the idea of gluing panels implies some level of stupidity that would make gluing wheels on rational - gotcha. Facts aren't your thing. Feelings are what matter.

Having some experience in the aviation industry (27 years), I can safely say that your implied faith in "aircraft builders" is misplaced as a concept. Do you see how many airworthiness directives come out on a weekly basis to identify and correct safety issues? Have you heard of the 737max? Have you heard of the 787 and its lithium batteries? The model of aircraft I owned had 3 design and manufacturing flaws that claimed lives. Fortunately for me, the aircraft was already 33 years old and had already killed enough people to sort out the flaws. Note that none of those flaws were associated with the bonded wing skins.

The tasks of designing an aircraft, the manufacturing methods, the processes and the labor to execute it is infinitely more sensitive to stupidity or bad decisions than your average DIY schmuck willing to follow written directions installing a solar panel on their roof.

How does that make you feel?

Screw down a panel, and I can almost guarantee you I can personally rip it off one corner at a time. Properly tape one down with VHB, and I'll probably slip a disc, rip a part of the roof off with the panel (the bond will be stronger than the roof) or put my foot through the roof because it can't take the downward force.

Opinions aren't facts. Because you don't understand something, and it scares you, it doesn't mean the solution that feels safer is correct.
 
Some of us DIYers have corrected the aerospace industry gods.

(A passion for understanding how things work can trump the long established engineering approach and validation methods.)
 
I just couldn't establish if you're mocking the nanny state or embracing it. The latter it is. People really should be arrested for not screwing down their panels, and the idea of gluing panels implies some level of stupidity that would make gluing wheels on rational - gotcha. Facts aren't your thing. Feelings are what matter.

Having some experience in the aviation industry (27 years), I can safely say that your implied faith in "aircraft builders" is misplaced as a concept. Do you see how many airworthiness directives come out on a weekly basis to identify and correct safety issues? Have you heard of the 737max? Have you heard of the 787 and its lithium batteries? The model of aircraft I owned had 3 design and manufacturing flaws that claimed lives. Fortunately for me, the aircraft was already 33 years old and had already killed enough people to sort out the flaws. Note that none of those flaws were associated with the bonded wing skins.

The tasks of designing an aircraft, the manufacturing methods, the processes and the labor to execute it is infinitely more sensitive to stupidity or bad decisions than your average DIY schmuck willing to follow written directions installing a solar panel on their roof.

How does that make you feel?

Screw down a panel, and I can almost guarantee you I can personally rip it off one corner at a time. Properly tape one down with VHB, and I'll probably slip a disc, rip a part of the roof off with the panel (the bond will be stronger than the roof) or put my foot through the roof because it can't take the downward force.

Opinions aren't facts. Because you don't understand something, and it scares you, it doesn't mean the solution that feels safer is correct.
Alright you win. But I have 40 years in aerospace. Just a measly NC programmer.
And I wasn't serious about cops checking RVs.
I will avoid driving near RVs from now on.
 
I'm not a materials or structural engineer but here is my research. I am certainly open to be educated further.

3M VHB Tape has 70lbs/sq in tensile strength on an aluminum surface (reference)
A #10 wood screw into 3/8 plywood has 205lbs withdrawal load (reference)

Thus 3 square inches of tape is the "equivalent" of a a single screw. Tape has the benefit of distributing the load over the entire surface taped rather than single points of failure. 8 screws = 1680 lbs. 12 screws = 2460 lbs. 30 sq in of tape = 2100 lbs

Clearly proper surface preparation and installation is important for either method. My roof is fiberglass. I need to research whether adhesion to fiberglass is better or worse than aluminum.
3M VHB Design Guide (link)
I'm sure if you under or over torque your wood screw it would impact your withdrawal strength as well.

Solar panels are wind rated in Pascals. For reference, 1 Pa = 0.02 lbs/sf. My panels are rated at 2400 Pa. That = 48 lbs/sf. So per my calculation if I had more than 14.7 sq in of tape, I would exceed the rating of the panel itself. I expect to exceed 30 sq in of tape per panel, significantly more if I go with a rail install.

If your roof has a metal frame clearly screws into metal would have a significant advantage over a screw into wood.

Do your research. Over design. Be safe
 
I just couldn't establish if you're mocking the nanny state or embracing it. The latter it is. People really should be arrested for not screwing down their panels, and the idea of gluing panels implies some level of stupidity that would make gluing wheels on rational - gotcha. Facts aren't your thing. Feelings are what matter.

It's really no different to an insecure load in the tray of a truck etc If it's not secured properly you should be in trouble with the law.

At least in Australia (QLD, NSW, Vic certainly so and probably the other states), if you drive with an insecure load the cops are going to pull you up and it's going to hurt your wallet a lot. An insecure load could be a load of bricks with a tarp tossed over it. No good. It has to be properly secured.
 
I run a small RV solar business. I’ve had customers ask me to “glue” panels down. I know there are people and products that make it work however I will not use glue alone. Every panel I install gets 4 screws plus a form of “glue”.
 
At least in Australia if you drive with an insecure load the cops are going to pull you up and it's going to hurt your wallet a lot. An insecure load could be a load of bricks with a tarp tossed over it. No good. It has to be properly secured.

Meanwhile in America..... ?
https://i.pinimg.com/originals/87/b4/09/87b4099fedd91142599736aa9aaa3cde.jpg

Flickr user Larry Myhre

https://i.imgur.com/ZHPP4we.jpg

https://i.imgur.com/Exufek8.jpg

https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fwww.saltlakecriminaldefense.com%2Fwp-content%2Fuploads%2F2015%2F08%2FUnsecured-load-600x315-cropped.jpg&f=1&nofb=1


In all seriousness, I'm sure that at least 4 out of 5 of these would be illegal here. But apart from maybe commercial loads, I don't think we have nearly the level of enforcement or clear guidelines/rules you have over in Australia.
 
I think the key points i got from the articles I linked are

Understand what you are attaching and what you are attaching it too.

Choose an appropriate attachment method

Use the correct materials for the attachment method.

Prep the materials correctly and diligently.

Form the attachment correctly and diligently.

Check it on a semi regular basis

Stuff flying off roofs is bad and to be avoided.

It doesn’t matter if it’s screwed and/or glued and what ever else. If it’s done badly with incorrectly matched materials it will be a bad join and therefore unsafe over time.
 
Anything dangerous needs to be fool proof. Do you realize you might be encouraging a fool to glue panels to his roof? A couple screws or a tether could have saved lives.
I am not encouraging a fool to do anything, I am encouraging people to use the right adhesive. A fool is quite happy being ignorant
 
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