Installing solar panel on roof of JayFlight SLX 264BH

[RoadAdventurer]

My JayFlight SLX 264BH came with a 100 watt solar panel installed on the roof. It looks like its screwed into the roof. I want to add another panel, so
I bought a 200 watt Renogy panel but am not sure on the best way to mount it. I have been reading some of the posts on this forum to get ideas.

It seems there are two schools of thought. One is to go no-holes and mount the panel to rails or struts that are attached with adhesive or adhesive tape, the other is to use screws to attach brackets. I rather like the idea of no-holes however some of the posts suggest that when you mount with just adhesive or tape, you are only bonding to the membrane on the roof which may or may not be bonded completely to the roof panels.

I reached out to Jayco support for advice and they replied "We cannot advise or recommend any modifications be done on the from the original build of the unit". However, they did provide a schematic of the roof. The schematic appears to show the that .34 plywood is used on the roof and I suspect after the plywood there is empty space until the ceiling panels (aside from any wiring or ducting that's in there)..

My original thoughts were to use well nuts as anchors and screw brackets to the roof , however I don't think that would work well with the thin plywood. I could screw into a roof truss, but I am not sure I can safely locate them with my stud finder.

Has anyone installed a solar panel on a TT with a similar roof? Did you go the adhesive route or the screwed route? I'd appreciate your thoughts.

Thanks in advance.

[Jayhawk 29]

Well I would begin by accessing the location of the current solar panel mounted on the roof. Consider the location that may be along one side as it compares to your ducting in the ceiling. This will tell you about the area to be cautious when running screws into the roof. Normally the solar panels are installed with their own solar panel brackets. And they come with fasteners. There are corresponding duct work on both sides on mine, one duct on one side of my AC going foward and the other side going aft on the plans that Jayco sent after sending their service department an email.

Now I did modify my mounting screws for the brackets when mounting them along the edges. I used a form of panhead hexhead slotted screws. I did use the factory supplied screws on the inside brackets. Now if you wish to see what the factory used, maybe pull one from their bracket and see what they used.

You can always bed them back down and cover them with the same caulk, possibly Dicor when you mount the new panels. I always use caulk under the bracket and across the bracket when done. Dry fit your brackets mounted on the solar panel. Pilot bore a small hole for realignment when going back down with the caulk. This keeps the burrs and slight sawdust from being in the mix if you dry screw your fasteners down and thru the brackets.

[RogerR]

I simply used the Renogy provided screws and mounting brackets. i did take my handy roll of Etearnabond and cut out a patch for each foot about 1 inch bigger all round the foot and applied it to the roof membrane. I then installed the feet which were attached loosely to the solar panel. This made sure the placement was correct. Applied a bit of Dicor on each screw and after it was set up I slapped a patch of Etearnabond over the screw heads.

[jimmoore13]

FWIW, I mounted my Renogy panels with the drill-point lags that came with the panels. I have no HVAC ducting in my ceiling, and gravity takes care of wiring, etc. above the ceiling so the lags pose virtually no risk to wiring above the ceiling so long as you keep a bit of distance from things like your roof vent/fan.

• Install the charge controller so that it is connected to your battery bank and to the gland on the roof...if you have solar already, this should already be done. You want the charge controller connected to the battery before you connect the panels to the charge controller. See instructions with charge controller.
• Layout the panel(s) location.
• Assemble panels/brackets.
• Mark drill holes with a Sharpie.
• Assemble wiring. In my case, 4 panels in parallel, so I had 2 panels in parallel with adapter/connector X 2 plus a 3rd parallel adapter to join the two sets. I paired up each set of two panels, fiddle farted around with the wire to dress it out as I wanted...all connections under the panels, then paired up the two sets...also with connector and wires under the panels.
• Place the panels to match the Sharpie-marked drill holes and double check the wiring is tucked away without causing issues.
• Connect to the gland or add a parallel connector, or wire in series, to your existing solar panel-to-gland connecting wire per your design.
• Test the system prior to anchoring panels to the roof.
• Brand new, premium grade drill bit about two sizes smaller than the lags to drill pilot holes through the roof membrane and into the roof sheathing below. This part seems redundant with the drill-point lags, but I didn't want to risk snagging and tearing my EPDM roof membrane with a faulty drill-point on one or more lags.
• Clean the roof membrane where the brackets will connect using something like 90% rubbing alcohol. It's gentle, but it cleans, and it dries very quickly.
• A tiny bit of Dicor caulk in the pilot holes and on the lag threads.
• Butyl Tape under the brackets between the brackets and the roof. This stuff is sticky and squashes out when you snug the lags.
• Fasten the panels to the roof. DO NOT OVERTIGHTEN THE LAGS. Jayco already confessed to sheathing the roof with "plywood" that is LESS than 3/8" thick. 3/8" = 0.375. They said 0.34" sheathing. Feel free to use a drill or impact driver to drive the screws in to ALMOST SNUG, but then use a hand nut-driver to finish the job. Some of the biggest problems in RVs are screws stripped out due to using power tools to drive the home. Hand tighten ONLY.
• Slather on a generous amount of Dicor Self Leveling Sealant over each bracket and lag.

It appears the water's over the dam on your purchase of the 200 watt add-on panel. Perhaps you can still return it and get 2 or 3 100 watt panels to take full advantage of your charge controller, which is likely to be able to handle 400 watts (30 amps). Your call on that.
Here is a primer for mixing and matching panels of different watts outputs...and issues with mixing voltages. Make sure that your existing panel is nominally 18 volts and that your 200 watt panel is also nominally 18 volts. If they are a mismatch, read on about issues that causes in the Bouge documentation. I found this Renogy 200 watt panel, and its voltage is nominally 18 volts (19+). This would likely be a good match for your current 100 watt panel.

If you are stuck with a 200 watt panel that puts out more like 36 volts, you could add a second 100 watt panel in series with your current panel to raise the voltage to about 36 volts.

My installation is 4 years old. It's as secure and dry as any other factory roof penetration...probably more so, because my work is far more meticulous than that of an RV assembler.