Community Forums

Jeepster360 · 04-10-2025, 09:35 PM

So I bought a 3rd zamp panel a few months back to supplement the 2 mounted on the roof from the factory. I'm worried about shading/shadow from the air con unit. I have read that if any shadow is on the panel, the whole panel output drops to basicly nothing. It can also drop the other panels output down (depending on how its wired) to the same level? I don't know but it concerns me. Has anyone mounted a panel above or on top of the a/c unit? Biggest concern wold be 65mph wind ripping it off the roof. Any suggestions?

John

Isaac-1 · 04-10-2025, 11:52 PM

It depends on the solar panel, most modern panels depending on their size have one or more bypass diodes, which allow panels to partly operate in partial shade. For example I have some 305 watt LG Neon series panels with 3 bypass diodes on each panel allowing them to operate in 3rds, so if only a small portion of the panel is blocked I will loose only about 1/3 of the output.

Cumminsfan · 04-11-2025, 09:18 AM

Pretty easy to go up on the roof, unplug one of the panels hook up a voltmeter and wave your hand over it.

FWIW my Grape Solar panels drop drastically with my hand shadowing a corner of the panel.

Jeepster360 · 04-11-2025, 02:14 PM

Quote:

Originally Posted by Cumminsfan

Pretty easy to go up on the roof, unplug one of the panels hook up a voltmeter and wave your hand over it.

FWIW my Grape Solar panels drop drastically with my hand shadowing a corner of the panel.

I'm sure the voltage will drop. That is why I'm looking to somehow mount the 3rd panel over/on the ac unit. It's a zamp panel like what came with the trailer. Do you know how the ac unit is mounted to the roof? Maybe I can tie into that somehow with some brackets? Any help is appreciated.

John

Cumminsfan · 04-12-2025, 08:26 AM

Quote:

Originally Posted by Jeepster360

I'm sure the voltage will drop. That is why I'm looking to somehow mount the 3rd panel over/on the ac unit. It's a zamp panel like what came with the trailer. Do you know how the ac unit is mounted to the roof? Maybe I can tie into that somehow with some brackets? Any help is appreciated.

John

AC is mounted to the roof with through bolts. It's a two piece setup with the bolts sandwiching the interior and exterior component's together.

I would not want to just attach a larger 190W panel to the AC shroud. Have you thought about installing the 3d panel somewhere else or better yet use it as a portable?

ORV has the Zamp connection just for that. I carry a 6th panel and use the Zamp outside connection for an additional 100W panel. I bought a small Victron 100/15 controller and mounted it inside the front storage compartment. Rewired it to the Zamp fitting. That way I can position the panel where I want.

spogdog · 04-12-2025, 09:26 AM

I have a third panel on the roof and I put it in front of the A/C. Yes it could get shadowed but that always changes when I move. As stated I wouldn't attach it to the shroud of the A/C as it's way to flimsy. I also have a portable that I connect to the Zamp side port. I didn't require it to a controller as I like to use the Zamp port to power 12v items like my Dometic portable fridge when I have it.

fda fa · 04-12-2025, 02:48 PM

Quote:

Originally Posted by Jeepster360

So I bought a 3rd zamp panel a few months back to supplement the 2 mounted on the roof from the factory. I'm worried about shading/shadow from the air con unit. I have read that if any shadow is on the panel, the whole panel output drops to basicly nothing. It can also drop the other panels output down (depending on how its wired) to the same level? I don't know but it concerns me. Has anyone mounted a panel above or on top of the a/c unit? Biggest concern wold be 65mph wind ripping it off the roof. Any suggestions?

John

If all are wired in parallel, then the loss would only be the shadowed panel.

Jeepster360 · 04-13-2025, 02:00 PM

Quote:

Originally Posted by Cumminsfan

AC is mounted to the roof with through bolts. It's a two piece setup with the bolts sandwiching the interior and exterior component's together.

I would not want to just attach a larger 190W panel to the AC shroud. Have you thought about installing the 3d panel somewhere else or better yet use it as a portable?

ORV has the Zamp connection just for that. I carry a 6th panel and use the Zamp outside connection for an additional 100W panel. I bought a small Victron 100/15 controller and mounted it inside the front storage compartment. Rewired it to the Zamp fitting. That way I can position the panel where I want.

Wasn't thinking of attaching it to the plastic shroud but maybe tie in to the mounts that hold the ac on itself. Not sure if that is even possible as it looks like the bolts come from the inside the trailer up to hold the ac on? As far as the zamp port, I do have a small,100w, panel for that to move with the sun.

John

Jeepster360 · 04-13-2025, 02:06 PM

Quote:

Originally Posted by fda fa

If all are wired in parallel, then the loss would only be the shadowed panel.

The panel I bought will plug into the 3rd, empty port on the roof that the other two panels plug into. Not sure how that is. Looks to feed Into a single wire that runs to the charge controller. Everything is factory-installed as of now. Just adding the 3rd panel.

John

Dave Pelletier · 04-14-2025, 09:07 AM

The AC mounting isn't that strong as it is and I certainly wouldn't want to try to mount a panel above the AC unit regardless due to the extra height and potential for damage. IF I was convinced I had to do this, it would be by fabricating a robust frame that attached directly to the roof, independently mounted from the AC unit.

I plan on adding a third panel soon and I'll just mount in on the roof like the other two.

Dave

fda fa · 04-14-2025, 06:10 PM

I have three 170W panels on 21RBS Anniversary-- Two parallel to camper length (one factory installed) and one perpendicular and behind the other panels. All wired in parallel. It is a little challenging to walk all the way to front of camper, while on roof, but other than that I am fine with arrangement. Stepping between panels is a bit uncomfortable but I don't hesitate doing so to wax the top of the front cap.

After connecting all panels make sure they are all working by covering up one panel at a time and checking current to battery. A shunt or BT lithium app makes this easy while on roof.

The Zamp connection box SAE connectors are marginal so checking that panels are providing power, on occasion, is worth the effort. Especially watch the SAE reverse adaptor, if using one. See if it is getting very hot when solar is running. Mine are still fine so I have no plans to make changes.

Shirt · Yesterday, 04:28 PM

I have a 24RLS and want to add a third panel as well. Is there anything to beware of when screwing the mount brackets to the roof? Or is it just plywood with no wiring or ducting to look out for if using inch and half screws?

fda fa · Yesterday, 04:47 PM

To be totally safe, when I mounted two more panels, I used screws that were no longer than washer, butyl tape, panel bracket, EPDM and roof plywood--to make sure that no wires were damaged. I do not know what the actual screw length was.

Cumminsfan · Yesterday, 11:31 PM

The roof ply is only 3/8" I used 1"x5/16" lags. I went through 1/8" aluminum and butyl. Then covered it with a heaping amount of self leveling sealant. Been up there for 19,000 miles.

Unless you hit a truss I'd be nervous with a 1.5" fastener.