How safe are roof mounted solar panels

[SFVdave]

Just wondering if anyone has ever had a solar panel fly off while driving in high winds? Doesn't look like the 2 screws for each of the 4 mounting brackets are secure enough to handle driving down the road at 75mph in Utah and have wind to boot.

[grizzzman]

Well we are on I80 doing 85 (wife is driving) And i "hope"my panels are still on. Good test i guess o and 45mph side winds.

Well we made it to camp. I made the panel brackets 3/16 T6 aluminum 3"angle (panels are 6" off the roof) 3 #10 screws per bracket dicor glued.

[SFVdave]

From the OP,
I have a filon roof too. I want to put a 150 watt panelon the roof. I have the room and access to the refrigerator vent nearby for wiring. Just worrying about the best way to mount a larger panel like that with just 4 or 6 Z-brackets and those short screws that the kits come with.

[tpi]

On my aluminum roof MH I used the 3M 5200 with eight brackets on a 100 watt panel-no screws. This was suggested by Lazy Daze factory even though the factory installed panels have one number 10 screw per foot. So far so good-up to 70 MPH with a headwind. This stuff really holds-but give it some time to cure before subjecting it to high speeds. I didn't put any real speed on it for a couple weeks. It is not something you want to do a day or two before your vacation.

[brulaz]

Rather than the tape or epoxy, with something like Filon, I would try 3M 5200 Marine Adhesive caulk with long (or lots of) brackets giving you lots of surface area to adhere to. Could drill holes in the brackets so the 5200 wells up into the holes. And would need weight to hold the brackets down while it dried.

Don't think screws would be necessary as that 3M 5200 is basically permanent. Pretty sure the Filon would rip out before the joint.

[Almot]

2oldman wrote:
As long as you have a 1/4" sheet of wood you'll be fine. This isn't wind tunnel testing.

Yes, but it could be 1/8" ply. In a 1/4" ply I would use 2 or 3 screws per bracket, with at least 3" spacing between screws. Ex., a 6" long piece of 3x3" aluminum angle with 2 or 3 screws, per corner.

DAS26miles - yes, a long bracket that spans the whole length of panel like on the Dusty's photo, would work. In 1/8 ply and with a long bracket like this, I wouldn't drive too many screws . Not "every few inches" for sure. Epoxy and 4 or 8 screws total should be enough. If you can locate rafters, it's always a good idea to drive screws in there.

[2oldman]

DAS26miles wrote:
So a filon roof is a problem I guess. Would a long l bracket screwed in every few inches work or would I have to screw thru thre roof and put washers and nuts on bolts? I don't thonk the DW would go for that.

As long as you have a 1/4" sheet of wood you'll be fine. This isn't wind tunnel testing.

[DAS26miles]

So a filon roof is a problem I guess. Would a long l bracket screwed in every few inches work or would I have to screw thru thre roof and put washers and nuts on bolts? I don't thonk the DW would go for that.

[BruceMc]

Heck, I've poked along at my normal 60-65, then done 90 trying to catch up with my brother who generally drives 75! It was the first test on those panels... they never budged.

Of course, they are glued & screwed to the roof/every cross-member I could find...



Link to (dusty) pics of Solar Install , for those who haven't already seen it....

We were in 40-50mph quarter winds in NE Colorado at 70 mph; steering wheel turned 30-45 degrees into the wind just to keep 'er rolling straight down the hwy. It was a white-knuckle trip... Those panels were on my mind the entire time, right along with the awning. Neither came loose.

Enjoy!

[Almot]

DAS26miles wrote:
My DW doesn't want me on the roof, so this may be a moot point. But I have filon too. What would I do to secure it, screws and dicor only?

Filon is different from rubber on 3/8 ply. In Filon you only have 1/8" ply, with (probably) block foam underneath. Regular tapping screws won't work. I would not rely on Dicor in this case and would rather use epoxy or VHB tape. Some people use well nuts in addition to Dicor (then Dicor becomes necessary to seal around the well nuts).

Also, do the roof mounted panels keep your batteries charging and or topped off while driving?

Solar works all day long. People don't turn it off for the night, or when they go fishing, or when driving.

[2oldman]

DAS26miles wrote:
, do the roof mounted panels keep your batteries charging and or topped off while driving?

Unless the wind can somehow blow away the sunlight, yes.

[MrWizard]

Roof mounted panels Work as long as there is solar energy to harvest
The controller will determine how much charging will be added, when other power is available
Example
The Blue Sky 2000e MPPT solar controller I had on there for just over four years , would always be on and add something to the system

But the Xantrex C40 PWM controller shuts off when my converter reaches over 13.8v, solar output is ZERO

It does charge when I'm driving

[DAS26miles]

My DW doesn't want me on the roof, so this may be a moot point. But I have filon too. What would I do to secure it, screws and dicor only?
Also, do the roof mounted panels keep your batteries charging and or topped off while driving?

[vermilye]

Shadow Catcher wrote:
The roof on our teardrop is Filon and our panel large. I did not want to drill holes and found ABS mounts that I imported from China. I called 3M and talked with one of their engineers about the use of 3M VHB tape and how much surface area on the mounts and surface prep I would need. He made a recommendation which I followed to the letter.
Three years ago we took a trip to California, hit those 40+ MPH head winds at 70MPH with trucks passing in the other direction. Wind loads, way up there and held on with tape.

For a number of years, Escape used VHB tape to mount panels on their fiberglass "egg trailers". My panel has been up there for 4 years with no problems, but they did have one blow off a trailer, and have since switched to epoxy.

[RJsfishin]

I can't even imagine the brackets letting go at any speed, but what keeps those hand tight black knobs from working loose, kinda amazes me.

75 mph ??? My tires come apart at 55, how would I ever get to 75 ??