Solar Panel Mounts on Thin Roofs

[Rustic313]

The build is progressing and I am now planning out "Phase 2" which will include mounting 2x100 watt solar panels on the roof of my 6x12. I am trying to figure the best way to do it.

My roof is thin aluminum (0.3"). The frame struts are 1" metal. The center of the roof is slightly higher but only because there is a strip of Luan in between the frame struts and the aluminum roof in the center. I haven't put the ceiling in yet so I have access to the underside.

OPTION 1: Z BRACKETS WITH SCREWS THROUGH THE ROOF
- Something like these Z feet (http://www.ebay.com/itm/Solar-Panel-Mou ... 27d61cce70)
- Screw the brackets in. I probably need to try and get them into the frame as the roof is only 0.3" thick.
- Use caulk on the screw threads, and Dicor sealant liberally on the roof.

I could also use tilt brackets for better efficiency but the install would be about the same. I am nervous about putting all those holes in my roof though! I'm worried about letting moisture into my trailer's frame or into the ceiling.

OPTION 2: VHB GLUE
- ABS plastic mounts (http://www.ebay.com/itm/Instapark-ZJ34B ... 5af167b185)
- VHB 3M tape (http://www.amazon.com/3M-Heavy-Duty-Mou ... B0016HM7SE)

No holes in the roof, but I am nervous about tape holding them on!



Any thoughts from those who have "been there done that?"

[Shadow Catcher]

I used VHB tape after a long conversation with a 3M engineer and it has stood up to wind speeds of 140 MPH. HOWEVER The mounts I have give a large surface area for attachment.The 3M engineer gave me the number of square inches I needed for wind load and the specific tape to use and the cleaner for prepping the surface.
It would be possible to make a tilt bracket with aluminum angle with sufficient surface area to work with VHB tape. My feeling is that in each case of camper orientation on a camp site that there was no choice in position and none of them would have allowed me any advantage from tilting.
The mounts are ABS plastic. One source http://www.amazon.com/Universal-Solar-4 ... m_sbs_lg_5 They also have the longer side pieces.
I imported ours from the manufacturer in China prior to them being available in the US.

[OverTheTopCargoTrailer]

Come on Shadow Catcher

I think at 140 MPH your pulling my trailer a little bit.....
is your TV a dragster or are you a tornado chaser ?
you would need to load your trailer down with 20,000 lbs of rocks & some good ropes....
for it not to blow away in 140 mph

joking aside

the VHB is some good stuff , I have used it myself with just some mickey mouse 2" Metal brackets on 210 watt panels
brackets were standing in water for 1+ years & it still sticks like hell.
I have also see lunch trucks on the freeway with those big plastic vents wide open at 45 deg and doing 55mph,
lots of guys drive their trailers with their roof vents open,
I put a air spoiler in front of my solar panels , to help keep the wind down.

[Socal Tom]

When I pulled my TD out from NC to CA I ran into a dust storm in NM with 60 mph head winds with 80 mph gusts. With the TV going 40 to 50 MPH the TD likely saw windspeeds of 120 mph or more... 140MPH doesn't seem that conservative to me.
Tom

[Rustic313]

I used VHB tape after a long conversation with a 3M engineer and it has stood up to wind speeds of 140 MPH. HOWEVER The mounts I have give a large surface area for attachment.The 3M engineer gave me the number of square inches I needed for wind load and the specific tape to use and the cleaner for prepping the surface.
It would be possible to make a tilt bracket with aluminum angle with sufficient surface area to work with VHB tape. My feeling is that in each case of camper orientation on a camp site that there was no choice in position and none of them would have allowed me any advantage from tilting.
The mounts are ABS plastic. One source http://www.amazon.com/Universal-Solar-4 ... m_sbs_lg_5 They also have the longer side pieces.
I imported ours from the manufacturer in China prior to them being available in the US.

I see that you have the four corner "feet" and at least two "bars" running along the edge of the panel across the width of the roof... I can't quite see in the picture, do you also have two more bars running fore and aft as well?

What size panels are those?

Mine are 100 watt and look smaller, so I'm guessing that four corners plus two of the center pieces with VHB would probably meet the same specs as your install.

[Rustic313]

Ok, I've got it priced out and the ABS plastic no-drill mounts will run about $50 each with shipping (http://www.unlimited-solar.com/) plus VHB tape ($35 on Amazon).

Youch!

Even tilt mounts are cheaper than that.

I'm thinking about doing one panel with tilt mounts and the other just flat with cheap "Z" feet and drilling through the roof. The shore power plug went in ok. I have a tube of dicor... Then again, holes in the roof make me really nervous.

[Shadow Catcher]

The Panel is a 180W high voltage panel and is about 5' long and the mounts are from this manufacturer http://brightsolar-power.com/index.php/product
I hate getting stabbed by high prices because something is labeled "solar", not unlike RV. I am seeing the four corner mounts with shipping at about $30.
On amazon Unlimited Solar has the mounts for $10 for the long mounts and the corner mounts for $30. You can make L brackets out of aluminum angle for a few dollars and if you used enough (long) you could mount using VHB tape.
One of my reasons for choosing the Bright Solar mounts is that the screw/bolt holes (which you have to drill yourself) are hooded. I used tamper resistant screws which were drilled and taped into the panel through the holes drilled into mount, and with out the proper bit you can not grab them with channel locks.
I have the two long mounts and the four corner mounts. and as Tom points out traveling at 65-70 MPH and bucking 40 to 60 MPH head winds gets you up there in wind speed and when you factor in passing semi bow waves I was being a bit conservative.

[OverTheTopCargoTrailer]

Hey Shadow Catcher

If I was a tornado chaser like you guys

Last thing I would worry about was my panels blowing off

How is it that the wind ONLY comes head on while your doing 70 MPH
Does the road never turn 90 deg ? So that you also get a nice side wind of 60 MPH ?
At what point & wind speed to you guys feel it's safer to park your rig ?

On my 39" x 64" panels this time I just made a L bracket from .030 metal
Used VHB along the 39" length & am using spacers to support the panels 1" raised
And I'm making a front spoiler, now I have 1,275 watts on my roof - 5 panels.
That covers about 85-90% of my trailer roof.
Not planing on going over 60 mph or fighting 60 mph headwinds in my 7 x 18 in my old age

Just my 2 cents worth

[Socal Tom]

Hey Shadow Catcher

If I was a tornado chaser like you guys

Last thing I would worry about was my panels blowing off

How is it that the wind ONLY comes head on while your doing 70 MPH
Does the road never turn 90 deg ? So that you also get a nice side wind of 60 MPH ?
At what point & wind speed to you guys feel it's safer to park your rig ?

In My case the NM Highway patrol closed I10 because the dust storms were so bad that you couldn't see the road. If I was having any trouble staying in my lane, or I felt like the trailer was tipping I would have pulled over. As it was I did slow from 75+ down to 40 to 50 mph. Under normal circumstances I might have had more trouble, but my TV and my TD were both well loaded with tools, 4KW generator, 3 dogs, and assorted other things.
Tom

[Shadow Catcher]

If you ride a bicycle you understand that unless the wind is from dead astern there is little advantage and that a quartering wind is still a problem. Last summer we hit a consistent forty MPH for days headed west, it sucked, gas!

[OverTheTopCargoTrailer]

Since I'm using lots more tape,
I seamed to have noticed it does not stick that well in hot weather

So maybe as a caution while in Furnace Creek at 125F .......
You may wanna keep the speed down to ONLY 125


IMHO

[Shadow Catcher]

Part of the equation to getting VHB to stick is pre-cleaning the surface. 3M makes a cleaner (heptane) for this purpose or you use a 50/50 alcohol water mix. http://solutions.3m.com/3MContentRetrie ... =ImageFile
We hit some serious desert temps last summer, not Death Vally hot but in excess of 110 with no problems.

[OverTheTopCargoTrailer]

I'm using about 3-4 times the amount of tape per panel as your feet,
Plus my trailer is much higher then my TV
But I still see some problems on the alum roof when it gets 125- 150 deg ,
This is happening easy due to the heat from the panels & my interior insulation,
Time will tell if mechanical fasteners may be better on the next model.

On a small trailer with taller TV your feet should work fine.


3M warrants for 24 months from the date of manufacture that 3MTM VHBTM Tape will be free of defects
in material and manufacture. 3M MAKES NO OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

[hankaye]

Howdy All;

Just to throw something else into the mix ...
has anyone thought or attempted to build a deflector
to route the airflow over the top of the Solar panels?

hank

[cornfused]

Howdy All;

Just to throw something else into the mix ...
has anyone thought or attempted to build a deflector
to route the airflow over the top of the Solar panels?

hank

earlier in this thread....

I put a air spoiler in front of my solar panels , to help keep the wind down.