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Solar Panel Mounting?


wamcneil

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Hi All,

I'm getting ready to replace my one original solar panel with four new ones.

The roof is a loose fiberglass skin and feels like a thin layer of thin plywood underneath. I'm thinking it would be impractical to find ribs to screw the mounts into.

Are the brackets just fastened into the plywood skin and plywood with wood screws? 

And on panel locations: the original panel is on the center-line just aft of the middle A/C. I'm planning to put one in the same location, and another immediately aft of it. These two shouldn't have much of a shading problem.

Then put two more panels on the road-side next to the front and rear A/Cs. My reasoning is that I can probably position the rig to minimize shadows if both panels are shaded the same way.

Picture attached. Does this sound like a good approach?

Thanks 

Walter

Solar_Layout.jpg

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I would not recommend mounting the panels with screws. I did and screwed into power wiring coming from the transfer switch. HUGE problem.  AM solar in Oregon only attaches pannels to fiberglass roofs with 'super sticky tape' Others may chim in, I learned my lesson. AM solar has good how to video's on their website.  

BigJon,  40 ft 99 executive M11-450

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4 hours ago, wamcneil said:

Hi All,

I'm getting ready to replace my one original solar panel with four new ones.

The roof is a loose fiberglass skin and feels like a thin layer of thin plywood underneath. I'm thinking it would be impractical to find ribs to screw the mounts into.

Are the brackets just fastened into the plywood skin and plywood with wood screws? 

And on panel locations: the original panel is on the center-line just aft of the middle A/C. I'm planning to put one in the same location, and another immediately aft of it. These two shouldn't have much of a shading problem.

Then put two more panels on the road-side next to the front and rear A/Cs. My reasoning is that I can probably position the rig to minimize shadows if both panels are shaded the same way.

Picture attached. Does this sound like a good approach?

Thanks 

Walter

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Walter

My solar panels are fastened to aluminum angles which are attached to the roof sub-straight with well nuts:

image.png.150a22ca2968f5e747d07b6fc1cb0083.png

Using Neoprene a WELL NUT

 

Edited by Mel S, '96 Safari Sahara
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Walter,

We have four large solar panels mounted on our fiberglass roof with the sticky tape brackets from AM Solar. I was concerned about these brackets holding up but AM assured me they would hold. They have been holding the panels for 5 years now and about 50,000  miles of travel without any issues. AM Solar did suggest that each bracket be covered with Dicor to keep the chemicals used to clean the roof from attacking the adhesive.

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7 hours ago, Bob Nodine said:

Walter,

We have four large solar panels mounted on our fiberglass roof with the sticky tape brackets from AM Solar. I was concerned about these brackets holding up but AM assured me they would hold. They have been holding the panels for 5 years now and about 50,000  miles of travel without any issues. AM Solar did suggest that each bracket be covered with Dicor to keep the chemicals used to clean the roof from attacking the adhesive.

I use the double back tape as well.  Works fine.  The tape is 3M/Scotch brand  VHB (very high bond)double sided tape . It is even used in some parts of aircraft assembly.  However, make sure the roof is clean before adhering the brackets.  I had a coating of Mop and Glo on my roof, and apparently I didn't get it all off before attaching brackets to the roof.  The tape stuck very well to the mop n glo, but the mop n glo came off the roof under one or two brackets.  Cleaned things up, reapplied with new tape, and they have been holding fine for two years now.  On my former coach, I held the panels down with just roof caulking for 10 years just fine.

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Ok, you guys have me convinced. It's VHB for me.

I looked at the AM Solar brackets. Very nice, but they cost $80 per panel... So I got a renology tilt bracket to try out. My plan is to adapt the renology mounts: using two of the extrusions for the back of a panel and then cutting short sections of 2"x2" aluminum angle for the attachment feet.  

I realize that I will seldom, if ever tilt the panels, but this should be cheap/easy mounting and allow the option of tilting.

Cheers,

Walter

solar.jpg

Edited by wamcneil
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I decided to make my own.  After all, aluminum angle iron is readily available.  After making my own, if I had it to do over, I would buy the brackets instead.  It was a PITA and took a lot of time to make them.  Bite the bullet and buy 'em!

Dave Jones

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17 hours ago, wamcneil said:

Ok, you guys have me convinced. It's VHB for me.

I looked at the AM Solar brackets. Very nice, but they cost $80 per panel... So I got a renology tilt bracket to try out. My plan is to adapt the renology mounts: using two of the extrusions for the back of a panel and then cutting short sections of 2"x2" aluminum angle for the attachment feet.  

I realize that I will seldom, if ever tilt the panels, but this should be cheap/easy mounting and allow the option of tilting.

Cheers,

Walter

solar.jpg

Walter,

We purchased the panel angling supports from AM Solar for each of our panels not because we ever expect to angle them but because they make it much easier to clean the roof. When washing the roof we tilt the panels up so we can get under them to clean.

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19 hours ago, wamcneil said:

Ok, you guys have me convinced. It's VHB for me.

I looked at the AM Solar brackets. Very nice, but they cost $80 per panel... So I got a renology tilt bracket to try out. My plan is to adapt the renology mounts: using two of the extrusions for the back of a panel and then cutting short sections of 2"x2" aluminum angle for the attachment feet.  

I used the AM Solar brackets for my install, and happy with them, but agree that the price was painful.

The place I bought my panels now have their own mounts of the same design, for a little bit less.  If/when I add more panels I may go for these:

https://www.continuousresources.com/collections/solar-panels-and-hardware/products/mounting-brackets-for-hightec-solar-panels-160w-210w
https://www.continuousresources.com/collections/solar-panels-and-hardware/products/mounting-brackets-with-tilt-bars-for-hightec-solar-panels-160w-210w

By the way, when I installed mine I bought only the AM Solar mounts bases, then built my own tilt bars; figured that was maybe an acceptable price compromise.

Jason.

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Ok, here's what I wound up with. I used the Renology extrusions on the panels and made some 3" long brackets from 1/16" 2x2 AL angle for mounting to the roof with VHB 4950 tape. This makes one $30 Renology kit work for 2 panels, plus my home-made attachment brackets and some additional hardware.

VHB 4950 is what AM Solar uses. I was concerned that a thick 1/8" extrusion would have no flex and might be too stiff to work with the VHB 4950 tape as the roof surface flexes. VHB 4950 tape uses 3M's 'firm' type foam and is quite hard, so both surfaces need to be very closely matched. 1/16" AL seems to be working well. The roof flexes quite a bit and the brackets also allow some flex. 

If I were starting over, I might use VHB 4941 tape which has 'conformable' foam.  It's not as strong as the 4950, but the softer foam might be easier to work with (and with 6sq-in per bracket, tape strength shouldn't be much of a factor...). 

So, now we'll see how they hold up... I've got 2 more panels to mount, combiner box, the new controller and a bunch of wiring...

Cheers,

Walter

 

IMG_2276.jpg

IMG_2274.jpg

IMG_2275.jpg

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Walter, if you are planning to use your coach in the winter when the sun is at a low angle you will almost certainly have shading on the panels from the AC units. After putting all the effort into adding solar the last thing you want is any shading especially considering the short charging hours in the winter. Consider making some extension brackets that you can attach to the roof brackets to raise the panels that are on the shade side of any obstructions. They can just be simple rectangular aluminum plates with two holes. If you have a rivet-nut tool add rivet nuts to the holes, get some extra screw knobs to make it a tool-less job to attach. You'll also need to consider the amount of slack needed in your wiring to allow for the panels to be raised.

Good luck with your solar project... and if you do nothing else, install a Trimetric meter so you know the exact state of charge and replaced charge of your battery bank. We have solar on our coach and we also live totally off grid and we rarely ever have to run our generators, so I have a little experience with making solar work. The Trimetric is an absolutely essential tool to know if you are really charging your batteries properly.

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Thanks Glenn. 
I’ll experiment with extensions.
And I’m kicking myself for not setting rivnuts in the brackets. Still thinking about it, but half of the panels are stuck down at this point, so re-drilling and adding rivnuts will be a pain!

Cheers

Walter

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48 minutes ago, wamcneil said:

Thanks Glenn. 
I’ll experiment with extensions.
And I’m kicking myself for not setting rivnuts in the brackets. Still thinking about it, but half of the panels are stuck down at this point, so re-drilling and adding rivnuts will be a pain!

Cheers

Walter

I think I understand what you are saying and I'm not suggesting that the extensions are permanent or that you need them on all panels. I believe you have the L shaped brackets attached to the roof and I assume you have knob screws to secure the panels to the brackets, somewhat like the brackets and knob screws in my attached picture (mine are not from AM Solar).  Is my assumption correct?

The rivnuts would not go in the "L" brackets, they would at least go in the bottom holes of the extensions and maybe the top depending on the mounting brackets on your panels. The extensions would only be attached once you are settled where you are going to camp and you can see which panels will be affected by shadows. For winter boondocking you'll definitely want to have tilt bars so when you are on the roof attaching the tilt bars you can add the extensions as needed. No need to make extensions for all panels just a few for the ones that may be in a shadow from about 9:00 AM to 3:00 PM. A quick run up the ladder at those times will tell the story.

IMG_4604.jpg

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Thanks. We're on the same page. 

My brackets attach differently than AM solar (mine attach to the bottom instead of the ends), but similar functionality. 

In addition to the extenders, I was thinking that I should have installed rivnuts on the brackets instead of using wingnuts on the back side of the knob.

My roof layout is a little different. I've got 2 panels on the certerline and the rest will be on along the road side. So all of my shading problems are coming from the same direction..

Cheers,

Walter

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  • 4 months later...

If you have a rig with the raised side rails, mounting the panels on it makes for easy tilting. I made my own mounts out of aluminum U channel and wooden supports. 7 tilt and 2 fixed for 990W.

There was some concerns (not by me) that the panels would raise up at speed. I put small pieces of paper under the ends of the supports and they were still under after a high speed test run.

E1DDFD20-28FB-47C7-8F8B-075AF009C8AE.jpeg

6932A469-E642-4E97-8725-F816DE8535D2.jpeg

Edited by Ivylog
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  • 2 weeks later...

I installed 3x250W panels using screws and VHB tape. With screws use a small drill, stop when through the roof and probe with a small wire to avoid whatever. My panels are mounted higher to eliminate A/C shade etc. 

The panels have bypass diodes and series connected with a MPPT controller which results in more shade tolerance from trees etc than parallel panels. 

My 2014 install costs the same as more 12V panels with a PWM controller for the same total wattage. 

Here's a link to my solar. https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28119528.cfm

 

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  • 5 months later...
On 12/15/2019 at 3:10 PM, wamcneil said:

Hi All,

I'm getting ready to replace my one original solar panel with four new ones.

The roof is a loose fiberglass skin and feels like a thin layer of thin plywood underneath. I'm thinking it would be impractical to find ribs to screw the mounts into.

Are the brackets just fastened into the plywood skin and plywood with wood screws? 

And on panel locations: the original panel is on the center-line just aft of the middle A/C. I'm planning to put one in the same location, and another immediately aft of it. These two shouldn't have much of a shading problem.

Then put two more panels on the road-side next to the front and rear A/Cs. My reasoning is that I can probably position the rig to minimize shadows if both panels are shaded the same way.

Picture attached. Does this sound like a good approach?

Thanks 

Walter

Solar_Layout.jpg

Have you looked into these, as recommended by Will Prowse? You use 3M VHB tape to secure them to the roof without drilling holes.

https://www.amazon.com/gp/product/B01MQF8BL1?pf_rd_r=CCZH9D664P0XSDN64C26&pf_rd_p=9d9090dd-8b99-4ac3-b4a9-90a1db2ef53b&pd_rd_r=2f9d9dba-551f-482a-8b0c-499fb00c5448&pd_rd_w=ORgOC&pd_rd_wg=1gFQh&ref_=pd_gw_unk

ED            

'05 HR Ambassador

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