RV Solar Panel Mount - Aluminum Brackets, Galvanized Steel Fasteners? 3

[CorruptedNova]

Greetings,

I hope this is an OK place to post this question. I'm looking for advice on how I've chosen to handle attaching (3) solar panels to the roof of my RV. I recognize this isn't a professional question, but I can't think of a smarter bunch of folks to ask this.

I have an RV. On the roof of that RV, I have two aluminum rails that run the length of the roof. This rail is attached to the RV via 'cleats' from the factory that rotate 90 degrees. Simple enough. However, the solar panels that I purchased are too perfect of a fit for the spacing of these rails, resulting in needing to use brackets to allow them to fit atop the rails properly. As well, I needed more clearance than the rails provided because of the curvature of the roof. I purchased the aluminum, cut the brackets, etc, and have it all installed. It turned out fine, I think, but I worry that I don't have the prerequisite knowledge of material chemistry to put my faith in this long-term.

I've attached a diagram showing what my original model was. It turned out exactly like what was pictured. The rails I purchased were a weird size, so I used 1/4" aluminum to create my own channel nuts. Everything is fastened with yellow zinc-plated 1/4-20 bolts, directly tapped into the aluminum. Each corner has this series of brackets, so 4 per panel, or 12 total.

My questions are this:

- Should I be worried about relying on aluminum threads for these mounts? I had to do this without nuts because of how close the bolts are to the rail, which is determined by the width of the solar panel. The entire assembly feels extremely strong, but that's not exactly scientific.

- How concerned should I be about the zinc plated screws threading into the aluminum? When I did my first round of research, it seemed like the answer I got was 'don't worry about it'. Naturally, now that I've finished, I am indeed worried about it.

Thank you very much for reading, and I'd greatly appreciate feedback if possible.

Edited to add the following details that I left out:

- I live in Michigan, cold and wet in the winters and hot in the summers.
- Aluminum is all unprotected and raw.
- Blue loctite on all fastener locations.
- Ideally quite permanent, so hopefully not ever removing.

 

[TugboatEng]

I would ditch the zinc plated fasteners or stainless. The zinc coating is thin and will wear away quickly. Are you in a coastal region or somewhere that is wet all of the time. Are the aluminum components anodized or raw? If it's well anodized some silicone grease goes a long way to protect thee aluminum from the fastener. A hard fiber washer between the two is better. Of you plan to remove and install fasteners regularly I do recommend inserts.

 

[CorruptedNova]

@TugboatEng

Thanks for your reply! I added these details to the OP.

- I live in Michigan, cold and wet in the winters and hot in the summers.
- Aluminum is all unprotected and raw.
- Blue loctite on all fastener locations.
- Ideally quite permanent, so hopefully not ever removing.

I'll consider upgrading to stainless. If I removed the current fasteners, should I be worried about compromising the integrity of the aluminum threads? The blue loctite might prove to work against me here.

Also, regarding the hard fiber washer, would the threads of the bolt versus the aluminum negate whatever benefit of the washer?

 

[dvd]

Look at the galvanic series -

http://www.eaa1000.av.org/technicl/corrosion/galvanic.htm

Fastenal has a nice compatibility chart -

https://www.fastenal.com/en/70/corrosion

 

[CorruptedNova]

@DVD, thank you very much for sending this over to me - it's fascinating to say the least.

I am a bit daft though, please forgive me. According to the Fastenal chart, it appears that my combination yields a '1', ie the corrosion of the base metal is not increased by the fastener. What am I missing?

 

[dvd]

CorruptedNova - you are missing out on other opportunities by worrying about this.

You may end up with more corrosion due to environmental aspects, such as rain pH, and as TugboatEng mentioned there is thin plating on mechanically galvanized fasteners. Swap your fasteners every couple of years.

 

[CorruptedNova]

@dvd

That's what I like to hear! Thank you for your input. I will move on to the myriad of other things I have to worry about, as you wisely suggested Have a great rest of your day.

 

[TugboatEng]

No, there should be no issues removing the fastener. Blue Loctite is very commonly used by engine builders for steel fasteners in aluminum. It too will protect the threads from corrosion. I'm just not used to bolts coming loose. It hasn't been a common occurrence for me so I never think to use Loctite even when the manual suggests it

 

[dArsonval]

Through the years reading the many posts on this site, I have to say the illustration used to describe the topic at hand is one of the better ones I can recall.
Computer generated drawings tend to be stale and lacking a "soul", but not the one in this thread. Including the parts list identifying the assembly nomenclature.

Have fun in that RV!

John

 

[CorruptedNova]

@TugboatEng

Haha, perfect, thank you for your input! I didn't think about it protecting the threads from corrosion, I'll do some more reading on that and see what I come up with.

@dArsonval

Thank you for your kind words! I am a technical writer these days now, so hearing feedback like that is amazing.

 

[hydtools]

True enough about Loctite sealant/adhesive. It keeps the necessary electrolyte component from completing the galvanic circuit.

Ted