Flat Panel Replacement

By Robert Oakman and Bob Kelly
February 11, 2021

Rob Oakman has a 19D with flat ‘flexible’ solar panels mounted on the roof. When Winnebago manufactured the unit, they did not install flat flexible Zamp Panels, and substituted SunPower panels. The rest of the system is Zamp products. Rob was concerned amount the heat transferred to the roof, and the subsequent potential damage to the roof, i.e.: crazing and discoloration of the fiberglass, and opted to replace the panels mounted on the roof. The panels worked perfectly, both before and after removal.

Rob ordered a 200W and 100W Renogy panel from Amazon. Since the roof appliance for the Zamp panels is an SAE connector, and the majority of the solar panel manufacturers use MC4 connectors, he purchased SAE to MC4 connectors. Zamp polarity is the reverse of the Renogy, so gender changers were also purchased. Renogy sells Z brackets to attach the panel to the roof, unfortunately, the brackets attach in such a manner that the panels cannot be removed from the feet, once the panel assembly is affixed to the RV. I had machined aluminum offsets manufactured, that allow the panel assembly to be removed from the RV without difficulty.

Prior to removal, the Z brackets were mounted to the panels. The Z brackets should be mounted to the panels so that the long axis of the Z bracket will be parallel to the long axis of the RV. Red locktite was used to secure the nuts and bolts. The bolts were installed so that if the nut fell off, the bolt would still go through the panel and the Z bracket. The aluminum offsets were then hand tightened to the Z brackets, as the solar panel would be removed immediately after mounting, in order to caulk the edges of the offsets. The solar panels were then turned bottom side up, and the 3M 4952 VHB tape was applied to the offsets.

The flat SunPower panels are affixed to the roof with six ¾ inch self tapping screws, butyl caulk, and what appeared to be Dicor. The screws were topped with a dab of Dicor. Removal consisted of removing the screws and then attempting to remove the panels without damage. The caulk and Dicor affixed the panels to the roof sufficiently; screws were un-needed. The panels were removed by carefully scraping the fiberglass roof with putty knives and plastic razor blades. The Dicor came off reluctantly. The butyl caulk was really sticky, and was more difficult to remove. Denatured Alcohol and a 3M pad and elbow grease completely removed the butyl and the Dicor.

The roof was completely cleaned using denatured alcohol, plastic razor blades, the putty knife and 3M pads. Once the roof was cleaned, the screw holes were filled with caulk, and the screws were inserted. Covering them with Dicor was done when the standoffs were caulked after mounting. After re-inserting the screws, the panels were affixed. We used a small combination square to assist in locating the panels on the roof. The square allowed us to easily mount the panel the same distance from the painted portion of his roof. The general location of the panels was marked with pencil lines, offset from the actual location of the mounting feet/pads. The roof was again cleaned with denatured alcohol; the 3M scrub pad and a cotton towel.

Roof after removal of flat panel, prior to cleaning.	Rob cleaning roof.
Roof after cleaning. Notice crackling and discoloration.	Discoloration of roof.
Screw re-inserted in roof, prior to caulking.	Roof after cleaning. Note the image of the flat panel.

Examination of the roof revealed that water is retained under the panels. We were in New Mexico, had been in Arizona and Southern California, and had experienced no rain, low humidity and sunny skies for several weeks. Additionally, there was a crackling on the roof and discoloration. The discoloration appeared most prominent under the collecting cells. There were noticeable spots where it appeared the panels became very hot.

The panels were then mounted. The 3M VHB covering, to keep the tape from sticking, were removed; the panels were propped on foam or a piece of 2×4 to keep the panel elevated from the roof, until it was in the proper position. The foam/2×4 was slipped out on one end, then the other, and the panel was affixed. The solar panels were then removed, exposing the offset pads. Rob then waxed the roof, to afford additional protection, especially for the crazed section of the roof. The was was removed from around the offsets, so as not to inhibit the Dicor from adhering. The offset pads and the screws were then caulked, and the panels were re-attached and blue locktite was applied to the mounting screws. The SAE to MC4 connector end gender changer was installed. The panels were plugged in, zip tied and then a glob of Dicor was applied to hold them in place.

The mounted panels , prior to caulking and setting in place.	Pencil marks to assist the cleaning of the roof where the feet are mounted.
The offsets mounted on the roof and caulked.	Caulking the offsets.
Detail of the offsets, feet and panel at completion.	Panels plugged into the Zamp roof appliance.

In all, the removal of the old panels and installation of the new took the two of us about three hours, including a lunch break. Rob intends to use the SunPower panels as portable panels after obtaining a 25’ cable, allowing him to plug into the Zamp port in the wet bay.