Solar Panel Mount on Rockwood Ultralite 5th Wheeler

[Chris61]

I am about to mount an extra 800w (4 x 200w) of solar on the roof of my Rockwood 2622RK 5h wheeler, It came with one 190w solar panel and this is just enough to run my 12v Magic Chef Refrigerator. Panels are 670mm x 1500mm and I am planning to use 60mmx 60mm aluminium angle brackets around 500mm long.

My question is do I need to find a truss to get a good mount or can I just use multiple screws through the plywood roof panel. What have others done

[Lundy]

I mounted two 200 watt panels on the roof of my Rockwood Ultra Lite TT. The roof construction is the same as your FW. After my research I determined that finding the roof studs was impossible, and I do not believe that the factory installers use roof rafters either. Here’s what I did, I bought and used Sticky Feet mounts and used 6 mounts per panel. These mounts come as a two piece set which makes for the actual mounting much easier and removal if ever needed. They have a strip of VHB tape on the bottom. I modified them by drilling two holes in each foot and used #8 screws to secure them to the thin roof taking care that I didn’t stripout any of the screws. Each hole was filled with Dicor before inserting the screw. Finally covering them with a solid coat of Dicor. So I have VHB tape + Screws + Dicor. They have been up there for over a year and about 5,000 miles and are rock solid. Feel free to ask me any questions you might have.
Link to Sticky Feet Mounts - https://rvsolarstore.com/index.php?r...product_id=112

[doc73]

Will the charge controller you have a handle the extra capacity from your solar addition? Also make sure the panels have similar voltages because if they do not comparing it to the original 190 Watt panel it could actually provide less power than you should and would think it would.

[Chris61]

Originally Posted by doc73

Will the charge controller you have a handle the extra capacity from your solar addition? Also make sure the panels have similar voltages because if they do not comparing it to the original 190 Watt panel it could actually provide less power than you should and would think it would.

I am going to have the new solar panels going through the Victron solar controller and retain the original solar controller and panels seperately. This will mean I do have to find somewhere through the roof for another set of cables. I can get good access through the wall behind original solar controller on the edge of the steps up to bedroom. I would like to know if all the roof trusses are spaced evenly so I don't hit one when ftting the cables and would like to find them for mounting the solar panels .

The solar panels I will be using are from a range that use same voltage across different wattage panels so if needed to I can add some smaller panels at a later date

[Chris61]

Originally Posted by Lundy

I mounted two 200 watt panels on the roof of my Rockwood Ultra Lite TT. The roof construction is the same as your FW. After my research I determined that finding the roof studs was impossible, and I do not believe that the factory installers use roof rafters either. [/url]

Thanks for the feedback, on my previous 5th wheeler I used 2 full length aluminium strips the full length of the solar panels, a fair bit of overkill and only used Sikaflex 252 to secure them to the roof. This stuff will not let go, however if the roof membane lets go, it could result in lots of damage. I would like to add a further level of securing the panel into a rafter in each corner of the panel and a few extra screws into the plywood panelling.

The below photo is a 100w panel on my last 5th wheeler. The small section on the front was mainly to limit airflow under panel while travelling down the highway. I plan to use to smaller sections in each corner this time, it still will have a reasonable surface area to glue to roof though, I just want the extra security of screws as well

[HangDiver]

Don't know if this suits your needs or not.... When I added panels to my Micro-Lite I pulled the cover off the awning bracket channel and ran the cables down behind the cover.

Good luck with your install.

[Hclarkx]

I have eight panels on the roof of my Rockwood Ultralite. Some have been there 7 years and 40,000 miles. All with Z brackets. Several have been moved as I've upgraded over the years, so I have some eternabond patches where I've removed z brackets. Actually quite a few such patches. Another upgrade will soon take me to 2000W and leave more eternabond patches. No problem yet so I'm not changing my modus operandi. I do check them once a year. Some have been on there for six years. The Ultralite is stored outdoors in the hot CA central valley.

If I have a complaint, it's the thin luan roof on the Ultralite. I add a third screw to each z bracket because of that. Only two of the z brackets have screws into an aluminum rib. That was just luck.

[Chris61]

Originally Posted by HangDiver

Don't know if this suits your needs or not.... When I added panels to my Micro-Lite I pulled the cover off the awning bracket channel and ran the cables down behind the cover.

Good luck with your install.

Thats thinking outside the square, never thought of doing that. I will probably still go through the roof, but ideas like that may be helpful to someone.

[Chris61]

Originally Posted by Hclarkx

If I have a complaint, it's the thin luan roof on the Ultralite. I add a third screw to each z bracket because of that. Only two of the z brackets have screws into an aluminum rib. That was just luck.

What sort of screws do you use? Have you used expanding type products like a Ramset hollow wall anchor. I was wondering if they would expand in the styrofoam under the plywood

[Chris61]

The plot thickens a little, just came across this Forest River video. It looks like truss spacings are all different. They seem to be either side of vents and air conditioner locations. The video is a travel trailer, which has a flat roof, but gives me an idea. The video features the roof for about a minute from 2m 5s

https://youtu.be/YGJvdcKApdY?t=125

Next question is how thick is the plywood

[JohnnyPop]

This is where Rockwood units don’t excel…roof strength. While in theory it sounds like a great idea…”vacuum bonded bla bla”…it’s actually not, it’s a disaster in the making. Basically it’s a thicker version of the laminated wall (4” with a crown) and the aluminum braces are only placed at: front, rear, air conditioning, roof vents. In my opinion I wouldn’t be mounting anything up there unless it came from the factory with it. On my old trailer I had a custom roof rack lag bolted to the wood roof trusses and carried 2 full size kayaks up there for years without any issue. Not possible on my new Rockwood…the structure and integrity is just not there, heck…it’s not even plywood sheathed…I think it’s luan board. Last fall I was walking up there (I’m 180lbs) just to sweep off the slides and heard a crunch in one spot. Yikes. But then again Rockwood botched my roof as I have one interior ceiling panel that has delaminated from the foam core…Rockwood had sneakishly tried to staple fix it before sending it out the factory door. Stapling 1/8th panel board to foam…yep, that’s your Rockwood Difference boys! Such rigorous quality for a 2022 fifth wheel ��*��

[Hclarkx]

Originally Posted by Chris61

What sort of screws do you use? Have you used expanding type products like a Ramset hollow wall anchor. I was wondering if they would expand in the styrofoam under the plywood

I used the screws linked below. Three screws per z bracket. I drilled minor diameter pilot holes to minimize splintering of the luan. A bit of butyl rubber under the z bracket foot. Some eternabond over the screw heads. Use a light touch on the screwdriver. Snug enough to spread the butyl rubber (maybe go over the screws a second time an hour later to squeeze the butyl a bit more without needing much torque.

On panels that I thought might catch wind, I put three z brackets down each side with the middle one a foot behind the leading ones.

The styrofoam under the luan is not dense enough to do any holding. The longer self tapping screws that came with the z brackets were too long in my opinion. There are ducts and some wires run in channels in the foam under the luan. The chance of hitting something critical (electrical wire) is low, but would be a disaster if it did happen.

I was careful to drill the pilot holes just barely through the luan, again to not hit something important underneath and give the screws a good bite.

My rubber membrane roof was not well adhered to the sealed luan so VHB or similar was not an option. The butyl rubber is a seal. It has no holding power to speak of.

There are anchor inserts that could expand under the luan (forming a bit of a rubber ball IIRC) but that would require a larger hole and would be overkill. Panels an inch off the roof don't catch much wind.

https://smile.amazon.com/gp/product/...e?ie=UTF8&th=1

[corn18]

I tried to find the roof trusses with a stud finder and failed miserably. Then I posted a pic of my roof and someone pointed out that they could see the trusses in my photo. I'll be darned. I used unistrut to mount my panels. If I missed the truss, there was absolutely no holding power. Whatever they use to covert the trusses, I would not trust it to hold anything. And my rubber membrane is not trustworthy. Obvious that it is not severely attached to the underlayment and anything taped to it would not be safe.

[Chris61]

Originally Posted by Hclarkx

I used three screws per z bracket. I drilled minor diameter pilot holes to minimize splintering of the luan. A bit of butyl rubber under the z bracket foot. Some eternabond over the screw heads. Use a light touch on the screwdriver. Snug enough to spread the butyl rubber (maybe go over the screws a second time an hour later to squeeze the butyl a bit more without needing much torque.

On panels that I thought might catch wind, I put three z brackets down each side with the middle one a foot behind the leading ones.

The styrofoam under the luan is not dense enough to do any holding. There are ducts and some wires run in channels in the foam under the luan. The chance of hitting something critical (electrical wire) is low, but would be a disaster if it did happen.

I was careful to drill the pilot holes just barely through the luan, again to not hit something important underneath and give the screws a good bite.

There are anchor inserts that could expand under the luan (forming a bit of a rubber ball IIRC) but that would require a larger hole and would be overkill. Panels an inch off the roof don't catch much wind.

Hi Hclarkx, thanks for your thoughts, I like your anchor inserts idea and have found some that require a ½" hole. I actually had some from a previous job. I was worried about using them with the styrofoam below so tested them out in a piece of side wall 1½" thick.

The three photos below show different angles after I scratched the styrofoam out after installation to see the final result. I was happy with the way the inserts crushed the styrofoam and made a tight clamp. I was thinking of using 3 brackets, 1 in each corner and 1 in the middle but only using one screw per bracket to keep the holes to a minimum. These anchors are designed for internal use, however they will be well covered with lap sealant.