2024 TAB 400 Black Canyon – Intermittent Factory Solar Issue (Looking for Other Owners' Experiences)

GordoB · July 5

I'm hoping to tap into the experience of other 2024 TAB 400 Black Canyon owners with the factory-installed Victron solar system.

I've been working directly with nuCamp Technical Support for the past couple of weeks, and they've been very responsive, but we haven't yet identified the root cause. I'm hoping other owners may have seen something similar.

My trailer

Factory-installed flexible roof solar panels (nuCamp advised mine are Sunflare Flex SI310 310 W panels)
Two roof panels
Victron SmartSolar MPPT 100/50 controller
Victron SmartShunt

Symptoms

The solar system behaves very strangely:

Solar charging works normally during parts of the day.
During the brightest / warmest part of the day, the Victron controller frequently changes to State = OFF and charging stops.
Later in the afternoon or evening, the controller often wakes up on its own and resumes charging.
This pattern has repeated over multiple days.

Diagnostics completed

With the help of an electrical engineer (and a lot of patience!), we've completed quite a bit of troubleshooting:

Battery side of the MPPT is normal.
Inline PV fuse tested good and was replaced as a precaution.
MPPT communicates normally via Bluetooth.
We disconnected the incoming PV wiring from the MPPT and measured the incoming panel voltage directly.
During one failure event, the incoming PV wiring measured only 0.6–0.7 V, suggesting the controller was not receiving usable voltage from the solar array at that time.

I've also discovered what appear to be concealed factory wiring connections behind the cabinetry, but they are not accessible without disassembly.

I'm hoping to learn from other owners

Has anyone experienced similar symptoms, especially charging that fails during the hottest part of the day and later recovers?
Has anyone had the factory roof panels replaced under warranty? If so:
- What was the actual failure?
- How did nuCamp diagnose it?
- Was it the panel itself, wiring, junction box, connector, or something else?
Can anyone confirm where the factory roof panel wiring is connected on a 2024 TAB 400?
- Behind the radio?
- MC4 connectors?
- WAGO connectors?
- Another hidden junction?
Has anyone removed the interior panels and taken photos of the factory solar wiring? Those would be incredibly helpful.
If you have the same system, what PV voltages do you normally see on your Victron controller during a sunny day?

I'm communicating with nuCamp and they've been trying to help throughout this process and I'm trying to determine whether this is an isolated issue or something that other owners have already solved. If I get to the bottom of this with nuCamp, I'll gladly post the solution here so future owners can benefit.

Thanks very much!

Gord

elbolillo · July 6

When you check the history of the MPPT controller. Do you see any errors? This could point you in the right direction.

Are all the wiring connections properly seated and tightened?

Where is the MPPT controller located? I am not certain where the panels are connected together. My assumption would be that it is behind the fridge.

pthomas745 · July 6

Have they discussed the Sunflare solar panel failures with you? Your panel may be in the early stages of this situation described in the thread below:

https://tab-rv.vanillacommunity.com/discussion/19753/nucamp-warning-about-sunflare-solar-panel-failures-july-2025

There have been a number of questions asked in the past about the (fill in expletive here) wiring for the solar panels that is hidden and not accessible without taking the trailer apart. I'm not exactly sure if "anyone" from any trailer year has done so. and, yes being able to do this would be an incredible advantage. Nucamp seems to have a great talent of building the trailer around the crucial components that may need to be inspected or replaced at a future date. Any "loose" MC4 connector or poor crimp/WAGO connection cannot be inspected easily.

f1xedgear · July 6

Gord, your solar-panel issue sounds very much like what we experienced this past spring, though our 400 is a 2025 (build date July 2024). The Victron app would show charging in the morning and evening, but at midday, in bright sunshine, the charger would be off.

I’m afraid nuCamp tech support wasn’t all that helpful to me in this instance. So, I decided to go through our dealership. Our dealer said the panels have a 10-year warranty. After some back and forth with them (where I supplied pictures of the app readings, along with corresponding pictures of the sunlight hitting the panels at different times in the day, and, finally, a picture of my multimeter showing 0 volts at the panel wires going into the solar charger at midday with full sun), they conferred with nuCamp, and it was decided that our panels were bad.

Our dealer ordered a set of new panels from nuCamp. They arrived within about 2 weeks. It took two days for the dealer’s techs to install the new panels (they started late in day 1 and found the old panels were “being a bit of a pain to get off” due to the installation glue, so the job was completed on day 2).

This work was done in late May. So far the panels have been meeting my expectations. Have patience. (I lost mine more than just once.) Good luck!

- Erich

GordoB · July 7

Thank you Erich, hopefully I get my issue resolved as well. I appreciate you sharing your experience.

Bill&Suze · July 7

Hi @GordoB, we also have 2024 400 Black Canyon. Several months after we got it, while out on a trip, it became apparent that the battery was not being charged by the panels. I spent a lot of time trying to sort out the issue, finally gave up and took it to the dealer. Their two technicians quickly found that the two solar panels had failed (on guy commented that they "ohmed out.) there was maybe a two week wait for NuCamp to get new panels shipped, another two days to install and now things have been great. No problems. The @pthomas745 comment and included post above get at the heart of the matter.

GordoB · July 8

@elbolillo Yes, we checked the controller via the app….no error codes, but there is a standard message which outlines the conditions by which the controller shuts off. My suspicion is that the solar panel shorting or "ohm-ing out" occurs and causes the controller to shut down in order to protect itself. here is a picture of one of the 2 blemishes on my panels.

GordoB · July 10

Update on my 2024 TAB 400 Sunflare Solar Issue

I wanted to thank everyone who took the time to respond to my earlier post regarding the intermittent failure of my factory-installed Sunflare SI310 solar panels. The comments and shared experiences from this community were extremely helpful in pointing me in the right direction.

After several weeks of troubleshooting, I thought I'd share where things ended up.

My system was exhibiting very intermittent solar charging. The Victron MPPT controller itself appeared to be functioning normally, but solar production would often collapse during periods of strong sunlight. Through testing, I was able to largely eliminate the MPPT controller as the source of the problem and narrow the issue to the factory-installed solar array.

While inspecting the panels, I also discovered that both panels have visible blemishes consistent with those shown in nuCamp's Sunflare advisory. Combined with the electrical symptoms and the experiences shared by several owners here, that provided a much clearer picture of what was happening.

I worked with Jordan in nuCamp Technical Support, who consulted with the nuCamp Warranty Department. They recommended that my dealer submit a warranty claim for evaluation under the published Sunflare warranty process.

I'm happy to report that I received a call from my dealer today confirming that the warranty claim has been approved, and that two replacement panels are being shipped to the dealership for installation. Assuming the panels arrive on time, the installation is currently scheduled for August 11.

I really appreciate everyone who shared their experiences. Without those posts, I may have continued chasing the wrong component.

Once the replacement is complete, I'll come back and post another update with:

the replacement panel model (if different),
whether the installation resolved the issue,
and any observations that might help future owners experiencing similar symptoms.

Thanks again to everyone who contributed. Hopefully this information will help the next owner who runs into the same problem.

— Gord

SavvyNurseCamper · July 11

@GordoB So what was happening to mine as well as yours was while cold would produce a little power and then when it heated up would separate the connections and arch power across the gap causing the blemish that you photographed. I have seen some that melted into the skin of the trailer which I have been told would need to be sent back to the factory to be repaired. One of my panels was producing 64.4 watts cold and shut off when it got warm- which would correspond with what you were experiencing . The heat would cause the poor connection to separate and shut off the flow of power. Sometimes that separation would arch power and cause melting which I can see yours did. Will update you on mine as well. Sunflare states production is back to full strength and will help out NuCamp as much as possible .

GordoB · July 11

@SavvyNurseCamper Interesting…..when are you scheduled to have replaced? Who is doing the work…a dealer or Nucamp directly?

SavvyNurseCamper · July 11

@GordoB I am pushing to have MEL trailers in Placentia do the work. They are already factory repair center for Airstream trailers and Victron components . They in addition have a working relationship with Battleborn batteries. MEL discovered the issues while wiring in the DC to DC converter from my truck to the Camper and while checking on the Victron app found little to no power coming from my panels. They then pulled the refrigerator and isolated the wires coming from the roof and discovered the rear panel was producing nothing and the front panel would produce 64.4 watts cold and then cut off when it got warm. I involved NuCamp warranty, Sunflare and Sean( NuCamp rep) to my ordeal with Blue Compass of Henderson Nevada.

If MEL trailer is authorized then we would have two major repair shops here in Calif. One in San Diego ( Little Guy trailers ) repair guy John Schilling. The other in Placentia (Orange Co/ LA ) through MEL trailers run by Albert Romo. John spoke with me yesterday and said they were so backed up it was not until end of September that they could work on my trailer.

GordoB · July 16

@aditto Here is my original thread on this forum, I have included a picture of my panel blemish above….also, I have detailed my current status with my repair. Let me know if I can help you in any way.

2024 TAB 400 Black Canyon – Intermittent Factory Solar Issue (Looking for Other Owners' Experiences)

My trailer

Symptoms

Diagnostics completed

I'm hoping to learn from other owners

Comments

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