Solar Panel Install - Page 3

lenore · 06-13-2022, 12:15 PM

BobC exactly, I like Tito, but after seeing the structure of my Vita (Winnebago) and the issue screws not holding the Sunpower flexible panels down in high wind conditions, The Tape and Well nuts with Tito's method of using T Track with the benefit of collector easy replacement is the Best solution. Will know shortly on my planned 6k+ trip through the high winds of Nevada, Utah, Wyoming and more.

tim myers · 06-13-2022, 12:53 PM

I like the idea of the aluminum channels Tito used. I think using the Well Nuts for holding the channels down would be a merge of two great ideas.

I agree that the well nuts should expand normally and that the Styrofoam should give way to the well nuts. However, I do think it would be a good idea to know where wire runs are located so as to not drill into them. Something to limit the depth of the drill bit might help with this also.

The reason I asked the question was concerns with wood screws pulling out of the thin Luan board, so keep the ideas coming, this is a great exchange of ideas.

BobC · 06-13-2022, 01:24 PM

Tito used steel Unistrut channel, not aluminum T Track, which is what Lenore used. In my opinion, the aluminum T Track is, hands down, a better solution than the Unistrut.

Marine359 · 06-13-2022, 02:05 PM

Will somebody help me understand why you need to use T tracks if you’re using well nuts. If you want to remove the panel, you don’t need T tracks for that. The well nut bolts will back out if necessary; right? Is it because of the curvature of the roof, where bending the Z brackets won’t work?

BobC · 06-13-2022, 02:32 PM

Quote:

Originally Posted by Marine359

Will somebody help me understand why you need to use T tracks if you’re using well nuts. If you want to remove the panel, you don’t need T tracks for that. The well nut bolts will back out if necessary; right? Is it because of the curvature of the roof, where bending the Z brackets won’t work?

From what I can gather, here's what I see as the advantages.

1. Even though you only have four brackets attached to the T Track, you can mount the T Track with pretty much as many well nuts as you'd like, thereby minimizing the possibility of it coming loose from the roof.

2. It gives you the ability to mount different solar panels without having to plug and drill new holes as long as they'll fit the T Tracks. They don't need to be exactly the same width or length. They need to be at least as wide as your T Tracks and your T Tracks need to be a little longer than the new panels.

3. If you need to remove the panels for any reason, removing and re-mounting is much simpler.

Note that you can handle the curve of the roof with brackets made out of aluminum angle stock in lieu of Z brackets. The angle stock is bolted to the panel frame at an angle, while its base is on the roof.

Marine359 · 06-13-2022, 02:58 PM

Wow, thanks Bob.
Light bulb is now on.
And I suppose it really doesn’t cost more. Aluminum T track probably costs $25 for 8ft.
Please tolerate one more of my stupid questions:
If you have the leading edge faired with vinyl molding, and you have T tracks running longitudinally, with the trailing edge open, is that enough for water to drain out?

Oh one more. Do you need to Dicor the tops of the well nuts?

cruizerEd · 06-13-2022, 03:24 PM

Here's my two cents of having 2KW (12 180W panel) solar since 2016. This advise is for fiberglass or other solid material roofs and may not be applicable to rubber like roofs.

RV roofs need maintenance. You will have tank vents, air vents, antennas, front and rear cap seams, maybe a skylight, the roof itself, the panel mounts, the panel wiring, and the panels. All of this needs maintenance and your panels will make all of it harder. Doing it from a ladder is not practical so you need to be able to walk the roof and be able to lift the panels to get under them to clean, check and repair seals, and keep the roof in good condition. Your panel will be more or less laying flat and will get very dirty so you need a way to clean them which is easiest if you can walk on the roof.

As for installing the panels, do not drill holes in your roof to install them. I have most of mine installed with 3M VHB tape and one installed with 5200. VHB tape works well but you have to make sure everything lines up perfectly so that there is no constant (aka preload) in the mount. An example of this is a mounting foot that doesn't conform to the roof or doesn't line up with the solar panel such that it has to bend just a little bit to be bolted on. VHB tape is hard to use because you have to make sure all the parts are lined perfectly when you attach them to the roof. Once you have everything tweaked you can just stick it down. VHB tape mounts can be removed with care. VHB tape does not appear to need to be covered with a lap sealant leaving a very clean install. Be sure not to load your VHB tape until it has had time to fully adhere. This can take over 24 hours. Read 3Ms installation instructions and check out their adhesion graphs. AM solar mounting feet are a good choice because they will let you tilt the panels to clean and optimize solar. The feet and the brackets do need to be squared up with the roof before mounting. The feet are angle brackets with a tapered riser with three holes. None of my feet were exactly 90 degrees so I had to bend them a little to get them to lay flat on the roof. I also had to adjust the brackets that attach to the solar panel a little to get them aligned as well. If you install the feet without adjusting them you will build in preloaded stresses that will make the VHB tape fail prematurely. It also makes it hard to thread the wingnuts in when you tilt the panels.

5200 holds much stronger than VHB but may not be a good idea because you may have to move the feet to replace the panel. 5200 will conform to the surfaces so part alignment tolerances are looser. 5200 takes a long time to set up and is thin and slippery so you have to have a way to position the panel and mounts and hold them in place until it dries. You also need to mask against runs and drips. 5200 is nearly impossible to remove so if you let it run or drip and don’t clean it up before it sets up you may never get it all off. 5200 is UV sensitive so you will have to cover it with a lap sealant like nuflex 311 or whatever is appropriate for your roof. This looks ok but is not as neat as VHB tape. 5200 is virtually permanent; you will have a hard time taking it off. You could probably do all the panels in one day with VHB tape but it might take a week to do it with 5200. Pro's like VHB tape for this reason it's fast and probably good enough.

Solar panels are supposed to last a long time but this is if they are mounted in a fixed location like a roof. On an RV they are subjected to a lot more stresses and I have been told by the manufacturer and by AM solar that you should expect some failures. When a panel fails after say 5 years you probably won't be able to find the same panel or a panel that is even the same size. For this reason 5200 may be a bad idea because removing the feet will be very hard. VHB on the other hand is not too hard to scrape off.

BarryLS · 06-13-2022, 03:33 PM

Install the T track with the 5200. They will not come off but your mounts to the solar panels can be removed to take the panel off. Once you have the T track solidly mounted you'll be able to mount anything (within reason) by custom making any brackets.

BobC · 06-13-2022, 05:25 PM

Quote:

Originally Posted by BarryLS

Install the T track with the 5200. They will not come off but your mounts to the solar panels can be removed to take the panel off. Once you have the T track solidly mounted you'll be able to mount anything (within reason) by custom making any brackets.

5200 is great stuff but not for this purpose, it's permanent in every sense of the word. You might want to remove the tracks at some point. Plus, this thread is about mounting to either Winnebago's thin Filon roofs or rubber roofs, neither of which is secure enough for adhesive alone.

If I were to use an adhesive in addition to well-nuts, I'd advise using 3m VHB tape. It has incredibly strong adhesion plus is relatively easy to remove with a thin putty knife.

BobC · 06-13-2022, 05:47 PM

Quote:

Originally Posted by Marine359

If you have the leading edge faired with vinyl molding, and you have T tracks running longitudinally, with the trailing edge open, is that enough for water to drain out?

Oh one more. Do you need to Dicor the tops of the well nuts?

1. Personally, I wouldn't worry about fairing the front edge. With the T Tracks being secured by numerous well nuts, nothing short of a crowbar will rip the panels off. I think you're obsessing a bit about this issue. In any case, I wouldn't worry about water draining out even with a fairing.

2. Yes, you'll need an appropriate sealant under the T Track and on top of the screws. The well nuts have a flange that sticks up a bit. It might compress a bibut you'll still want some sealant under the track. You have a rubber roof so Dicor is appropriate for on top of the screws. I'd use Manus Bond 75-AM underneath. Winnebago doesn't publish sealant call-out sheets for it's towables but Manus Bond is specified for underneath fixtures on its motorhomes.

BarryLS · 06-13-2022, 06:14 PM

I wouldn't mount anything to a rubber roof without well nuts. For fiberglass including filon, I'd use the 5200. I've used it on quite a few things in the past and it is superior in terms of grip. But not if you wish to remove it in the future.

The problem with well nuts is the hole. One more thing you have to keep sealed. But that's the only thing I don't like, otherwise pretty simple.

Ontario Don · 09-23-2022, 07:55 AM

Great thread - Thanks for all the info.

Lenore and everyone - a couple of questions on the T Track and VHB tape install:

1 - The T Track... is that just standard 3/4" wide mitre track used in woodworking?

2 - Did you have any concerns with the gap between the well nut flange and the VHB tape? Or, the diameter of the well nut you used fits comfortably inside the width of the VHB tape?

3 - Did you need to add any Dicor to the hole area, either on the install of the well nut, or the inside of the track over the top of the bolt?

4 - Do you remember the size of the well nuts you used?

5 - 3/4" or 1/2" VHB tape?

Thanks for the help.

lenore · 09-23-2022, 08:21 AM

Quote:

Originally Posted by Ontario Don

Great thread - Thanks for all the info.

Lenore and everyone - a couple of questions on the T Track and VHB tape install:

1 - The T Track... is that just standard 3/4" wide mitre track used in woodworking?

2 - Did you have any concerns with the gap between the well nut flange and the VHB tape? Or, the diameter of the well nut you used fits comfortably inside the width of the VHB tape?

3 - Did you need to add any Dicor to the hole area, either on the install of the well nut, or the inside of the track over the top of the bolt?

4 - Do you remember the size of the well nuts you used?

5 - 3/4" or 1/2" VHB tape?

Thanks for the help.

The T track is 3/4 inch by 48 inches long.
The well nuts top is about the same height as the VHB tape. I elected to use dicor around all of the T track to prevent UV exposure to the tape and to seal the track to the rubber roof. The VHB was 3/4 inch wide. I have gone 6000 miles so far and the system is working very well.

Ontario Don · 09-23-2022, 08:57 AM

Great, thanks again.

One of my 100 watt Sun Power flex panels from the factory has lost performance; I expect the other might do the same at some point. I picked up some Renogy 100 watt rigid panels to replace and expand the system - good to know everyone is having success using the T track mounting system.

Cheers,