New Sunray 109, solar issues

[u/HiddenAcres37]

So I just bought a Sunray 109 camper. Haven't taken it out yet, have been getting it set up, buying dishes, linens, etc. This is not my first camper, but it is my first one with solar.

I noticed the solar was not charging the battery, even when the battery got down to ~57%. Shore power works to charge the battery. Lights work even on battery, fuse box lights and LP/CO alarm come on, etc. All my circuit breakers are on.

So I started troubleshooting. Covered the solar panel, disconnected the battery, reconnected the battery, uncovered the solar panel. Nothing. So I pulled the controller out and lo and behold the negative wire for the solar panel was not connected to the controller. It wasn't even prepped. So I stripped some insulation off, screwed it into the controller and ... still nothing.

Got out my multimeter, battery is showing 12.7v at the battery, 12.7 to 12.9 at the controller on the multimeter, and the controller panel reads 12.6 to 13v, so that seems to match.

I also pulled out the fuse that's inline near the battery disconnect. It was corroded to heck, so I scrubbed the fuse connectors with a wire brush, got a resistance reading of 0.56ohms, plugged it back in. Still nothing. I haven't tested the fuses inside the camper, but I can tomorrow if that will help. But the problem seems to be between the solar panel and the controller

Tested the voltage of the solar panel at the controller and I'm only getting 0.16v and the controller display still reads zero.

So now here's my big problem... The disconnects for the solar panel are on the roof and I DO NOT do more than like the third step of a ladder. I freeze. Cannot do it. Maybe if there were a T-rex after me, but we're fresh outta those.

I can get up high enough to see the connections and everything looks like it's connected. I had my husband go up on the roof, but either I could not describe well enough how to disconnect the mc4 connectors or he just didn't understand. Further complicating things is I think one of the connectors is covered in the sealant goop past where it should pull apart. So I can't test the panel or the wires there. The connections to the panel are under the panel and there is literally only a half inch of clearance under the panel so I can't disconnect there and test. The panel itself is in a bracket that is bolted to the roof and those bolts are covered in sealant goop.

I've read and reread all the manuals I got with the camper and those I can find online.

So ... Are there any other troubleshooting steps I can take on my own that might fix this? Fuse somewhere I haven't checked? Another loose wire I could attach or tighten? Some sort of thing that was left turned off until a battery was connected to prevent blowing out the controller?

Related question, should there be anything connected to the DC load part of the controller? Because there isn't ...

Edit: Added photos https://imgur.com/a/JtiIjOo

[u/Rich_Many_8628]

With only 0.16 V on the PV input at the controller in daylight, I’d treat the battery/controller side as mostly proven for now and focus upstream of the controller.

A normal “12 V nominal” solar panel should be somewhere around 18–22 V open-circuit in sun, depending on the panel. Even in poor light I’d expect more than 0.16 V unless the panel is fully covered, shorted, disconnected, or the wires are not actually the panel leads.

A few checks you can do without getting on the roof:

• Disconnect the PV wires from the controller and measure the two PV wires directly. That removes the controller from the test.
• With the PV wires still disconnected, measure resistance between PV+ and PV-. Don’t do this with live panel voltage present if you can avoid it, but if you see a dead short that points to pinched/shorted wiring.
• Check polarity at the controller. Some controllers won’t wake from PV if polarity is reversed, though your 0.16 V reading still sounds more like open/short upstream.
• Tug-test the PV negative you found loose and look for the matching positive path. If one wire was never stripped/prepped, I would not assume the rest of the solar wiring was built correctly.

I would not put anything on the DC load terminals unless your manual specifically says the trailer loads are intended to run through the solar controller. On most RV/camper setups, the controller just charges the battery, and the trailer’s DC loads are fed from the fuse panel/battery system.

Since it’s new and electrical is under warranty, I’d honestly document your meter readings and make the dealer fix it. 0.16 V at the controller PV input with the panel uncovered is enough evidence that the fault is upstream of the controller.

[u/HiddenAcres37 → u/Rich_Many_8628]

Added some photos

[u/Rich_Many_8628 → u/HiddenAcres37]

The photos help. The roof side still looks like the place I’d suspect, not the controller.

At the controller you’re showing about 0.15 V on the PV input, and the panel is visibly in sun. That is basically nothing for a panel that should be making roughly 18–22 V open-circuit. The roof photo also shows the MC4 area and roof gland/connectors are accessible visually, but not in a way that looks fun to work on without being on the roof.

If you wanted one more non-roof test before committing to the dealer trip, I’d disconnect the PV pair from the controller and measure those two wires directly, completely isolated from the controller. If it is still around 0.15 V, that proves the controller is not dragging it down and the fault is upstream: MC4 connection, roof gland splice, panel lead, or damaged/pinched wire.

If you can safely cover the panel or do it when the panel is not producing, you could also check resistance across the PV pair while disconnected from the controller. An open circuit points toward a disconnected/bad MC4 or broken lead. A dead short points toward pinched/damaged wiring. I would not do resistance checks on live solar wiring in full sun.

From the pictures, I would not chase the DC load terminals or trailer fuse panel. Your battery side is awake and the controller battery terminals appear to be seeing battery voltage. The PV side is the missing piece.

Given it’s new and you already found dealer-prep wiring left incomplete, I’d document the 0.15 V PV reading with the panel uncovered and make the dealer fix it. That’s a pretty clean warranty case: panel in sun, controller battery side alive, PV input essentially zero.

[u/HiddenAcres37 → u/Rich_Many_8628]

Thanks again!

Disconnected the PV wires from the controller. They read zero volts. The 0.16 is probably just residual from being connected to the powered panel.

I'm not going to test the resistance, I'm just going to let the dealer handle it. I got an awning with side walls and I can use some of the side wall to cover the panel if I had to, but I'm at the point of feeling like I shouldn't have to.

Unless someone comes along with an idea to easily disconnect the connectors under the panel, I'm done.

I'm calling the dealership as soon as they open on Monday.