azloafer:
Welcome to iRV2.com! I installed 570W of solar panels on our motorhome's roof over a year ago and have had no problems to date
. Our roof is TPO covered plywood, but installation in fiberglass would be similar.
There are other panel mounting methods, some of which use adhesive that require no drilling at all (3M VHB adhesive tape), but they cannot be used on TPO roofs, so I could not use them. Here's what I did:
I used wellnuts (
https://www.acehardwareoutlet.co/%28bnrp4j553iyxyo55z1ztynqt%29/ProductDetails.aspx?SKU=2147001895) to mount the panel's mounting brackets to the roof and sealed liberally with Dicor lap sealant. Note I bought them from our local bolt dealer, not the website I linked to.
I ran the wiring through the fridge vent, you should be able to do the same as long as your fridge has a roof vent. If not there are other ways to seal the hole you will have to put through the roof.
Since your roof is fiberglass you could use 3M 4200 (or 5200) sealent (
3Mâ„¢ Marine Adhesive/Sealant Fast Cure 4200) instead of the Dicor, I used it on window reseals on our last RV and it worked great, there are other positive reviews of it as well on this site and other RV forums.
Our system just charges the house batteries (I installed 1000AH worth of them), although the chassis battery gets charged when the house voltage is high enough because of our BIRD (
Bi Directional Isolator Relay Delay)
.
We really enjoy not having to run our generator every night when camping with no hookups
!