Renogy panel mounts, Micro Minnie

backtrack15 · 01-02-2021, 04:12 PM

I've got the first of two 100W Renogy solar panels ready to install on my Micro Minnie. I just need to attach it to the roof and plug it in to the factory MC4 connectors.

Since my Micro Minnie has the TPO roof membrane over 3/8" wood decking, I have to screw the Renogy mounting brackets to the roof. (The TPO is not a good base for an ultra-high-bond adhesive as the TPO itself could just lift off.) The Renogy mounts at the front of the panel (toward front of trailer) will be placed on a roof truss so that the leading screw on each mount is attached to the truss. The aft screw on each front mount will simply be through the decking. Both screws on both rear mounts will simply be through the decking. Obviously I'll use stainless screws (thinking #12) and seal the mounts with self-leveling dicor.

My questions:
(1) Has anyone experienced a fatigue failure of one of the Renogy mounting brackets? They seem a bit thinner and more flexible than I imagined.
(2) Do you think the plan above will provide a robust attachment, or do I need to look at using well nuts for the deck-only screws? I have no experience with panels and I'd prefer not to throw sharp 15-lb objects at the vehicles behind me.

Old Navy · 01-02-2021, 11:14 PM

I can't offer any first hand experience, but I will follow your efforts, as I will be doing the same job in the near future.

I've read of a few people that used well nuts, and one person even showed a reference where a manufacturer listed well nuts as an alternative installation method. My only experience with them was mounting a heavy duty roof rack on a jeep, something they are ideal for. But most folks just use screws, and that seems to be quite reliable also. If I went with well nuts, I would get the longest I could find to keep the bulge on the bottom side of the panel. They are really designed for thin panels, but the longest ones might work "well" for 3/8" OSB.

For those who place function over form, it wouldn't be hard to drill 1" holes in the luan ceiling panels to allow the use of nuts, bolts and washers through the OSB, then cover the holes with flush hole covers or panel plugs.

BobC · 01-03-2021, 05:53 AM

I don't see any significant advantage of using well nuts over screws in 3/8" decking. I've used both on two prior Nash TTs with 3/8" decking and never had a problem with either. Although through-bolting is going to be the most secure, it's overkill. The stresses placed on a properly mounted solar panel are much less than one would imagine.

I've never used Renogy brackets so I can't advise you on their suitability based on experience but I'd be surprised if Renogy was selling an inferior bracket. The flexibility may be intentional so your brackets can flex slightly to follow the curve of your roof. When I mounted solar panels on the van I'm converting, I made my own brackets out of 6" pieces of aluminum angle stock, screwed to the sides of the panel frame instead of the bottom. This makes it easy to remove the panel for service without disturbing the mount. I used 3m VHB tape to mount them to my fiberglass roof so removal of the brackets would be more complicated than removing a few screws. I used two brackets in the front and two in the rear. Since they're so long and rigid, each is angled slightly to follow the curve of the roof.

**creativepart** · 01-03-2021, 08:24 AM

You should be fine. Put Dicor both under and over your mounting brackets. Screw through the Dicor to cover the screws. Be generous with it. Water will always find a way in unless you block it entirely.

backtrack15 · 01-09-2021, 07:54 AM

I went ahead and installed the panel as discussed above (without well nuts). It seems like a pretty solid mount. I was generous with the Dicor. I'll report back if I detect any issues. Cleaning the panel will result in rather frequent inspections.

Desert Taco · 01-14-2021, 01:02 PM

backtrack15, I have 2020 2108DS and received HQST 100w kit for Christmas! Planning on installing this w.end but how did you find a roof truss to screw into? And did you add any kind of fuse between CC and battery?

Old Navy · 01-14-2021, 01:17 PM

If you look up on your roof, you will see that the 4'x8' 3/8" OSB panel seams telegraph through the roof membrane very clearly. These OSB seams correlate with a truss. There are two additional trusses between the seams at 16" on center, unless there is a vent or other obstruction. If there are obstructions where a truss should go, then they are shifted. In my Minnie, I can remove the vent over the bed and see/measure the truss location. I tried both a magnet and a stud finder on my roof and neither detected the trusses or nails below...

Desert Taco · 01-14-2021, 01:32 PM

Great info, thanks. I thought I'd try a stud finder but didn't have high hopes. Right now I'm on hold w/Dometic getting my 300 toilet replaced. One more thing down.

backtrack15 · 01-14-2021, 01:52 PM

Quote:

Originally Posted by Desert Taco

backtrack15, I have 2020 2108DS and received HQST 100w kit for Christmas! Planning on installing this w.end but how did you find a roof truss to screw into? And did you add any kind of fuse between CC and battery?

I added an in-line fuse to the +12V wire between the CC and battery (at the trailer tongue end). I added a 30-amp resettable breaker on the + line from the solar panels themselves (mounted it next to the CC), mostly as a convenient disconnect.

I tied into one of the trusses associated with the front roof vent.