Community Forums

vsheetz · 12-04-2012, 11:58 PM

Adhesive or screws for solar panel mounting? What have you used? Pros and cons? Ability to be removed if needed?

The wires running from the panels to combiner box - how best to secure them to the roof?

thanks!

Shadowcatche · 12-05-2012, 05:23 AM

I have a set of ABS solar panel mounts with large mounting base. I did not want to use screws and felt that 3M VHB tape might work. After talking with a 3M engineer at length about the calculations of necessary surface area which the mounts had. Proper cleaning and use of the correct VHB tape and I have a 185W panel mounted with no holes.
The plus side no holes and removable with a fair amount of effort (orange and a couple of types of solvents). It will stand up to wind speeds over 110MPH, but you need to have the surface area on the mounts.

mgscott4 · 12-05-2012, 05:45 AM

I used both screws and adhesives, sort of. I have a rubber roof and there is only 1/8th inch piece of Luan under the rubber. I used Molley bolts and Dicor self leveling sealant. The sealant has some adhesive features.

I used 2 pieces of aluminum angle iron bolted together with a slot in the middle in the shape of a Z. 3 Molley bolts per bracket on the roof, 6 brackets per panel for a total of 18 holes per panel. Dicor in each hole with the Molley bolt, Dicor on roof under each bracket, and Dicor over the top of each bracket after screwed down. No leaks yet.

The slots on the Z brackets allow for the slight curvature of my roof and allowed me to angle the panels down in the front for wind over the panels not under while driving. The bolts on the Z bracket allow for removal or tilting if needed without removing the sealed roof bracket.

The wires between panels and to the combiner box can be secured using the same Dicor self leveling sealant directly to the roof about every 2 to 3 feet.

Here are a few examples of what others have done.

RV.Net Open Roads Forum: Tech Issues: Forum Members Solar Installations With Pics

michelb · 12-06-2012, 07:05 AM

Most places I've seen say that with fiberglass roof, only using 3M VHB tape is the preferred way. With rubber roofs, you have to use screws.

wa8yxm · 12-06-2012, 08:24 AM

Screws or Adheasive...

BOTH

Lay the thing down and figure out where the screws will go

now lift it and lay a pad of adheasive (Or Dicor caulk) on the spot where the screw will screw in.

now lay the mount back down and insert screw

now Calk over the screw to completly seal

Strong (Thanks to the the screw) leakproof (Thanks to the caulk)

With two exceptions that is how everything on my roof is mounted.

Those 2.. Air conditioners, instead of screws it's bolts, and instead of caulk a foam gasket, but the concept is the same.

WheelingIt · 12-06-2012, 08:39 AM

We used only 3M VHB tape on our fiberglass roof. No holes and solid as a rock. Two years fulltiming with the tape so far and no issues at all. With a fiberglass roof I'd choose the same again.

alv3769 · 12-12-2012, 10:41 AM

i plan on using tape to mount my solar panels. does anyone that did this remember the number of the 3m tape they used?

Manuel B · 12-15-2012, 04:07 PM

The factory 50W panel was missing due to hail damage when I bought mine, I bought a 120W replacement which was much larger and I didn't want to drill more holes in my fiberglass roof so I went to the boat supply shop and bought a tube of marine sealant adhesive, the panel covers where the wire comes out, I didn't know about the 3M tape, what I used came in two flavors, semi or permanent, I picked permanent,

YC1 · 12-15-2012, 06:23 PM

I would not sleep well with tape only. I have seen this tape give up way to often. Four screws and the shear force to tear it off increases tremendously. If you use both and then cover with Dicor you should never have an issue. You can still take it apart as well.

TdogKing · 12-15-2012, 09:27 PM

I wouldn't trust just tape with expensive Solar Panels. I've driven in some pretty high head winds in the So Cal desert areas and wondered if anything was going to left on top my Motorhome when I got home !! Everything else on your roof is put on with screws and sealer so Solar Panels is no different. I mounted 3 on mine over 10 years ago and never had a problem but I take care of my roof also.

Shadowcatche · 12-16-2012, 04:48 AM

You have to do the calculations for surface area to make sure you have enough and you have to prep the attachment area. The semi's going down the road with no apparent rivets/screws in all likelihood are using VHB tape. The mounts I am using have a great deal of area.