24 T@B 400 Intermittent 12V Power Issue

floridaman · May 30

Hi all,

I’m looking for help diagnosing an electrical issue with my 2024 TAB400 Boondock Edition (lithium package). The camper was in storage for about six weeks with the battery disconnect switch engaged (so the batteries were disconnected). When I checked the Victron app, none of the usual components (shunt or solar) showed up. It was as if the system didn’t exist.

After plugging the camper into shore power, everything reappeared in the app, showing the battery at 100% charge. I unplugged shore power and the battery continued to display in the app, so I assumed all was good.

However, the next morning, the Victron app again showed nothing—no battery, no shunt, no solar—until I plugged the camper back into power, at which point everything came back and the battery still showed 100%. This pattern has repeated.

Another potentially related symptom: the solar shows 0W input over the last 5–6 days, despite being parked outside and several prior days showing 30-70 watt-hours

Has anyone experienced this behavior before? I’m wondering if the SmartShunt is acting up or if something else in the system might be causing the Victron to lose visibility to the battery when off shore power.

Thanks in advance for any insights.

elbolillo · May 30

can you take some detailed photos of your setup and post them?

floridaman · May 30

elbolillo said:

can you take some detailed photos of your setup and post them?

You mean take pictures of the battery? Apologies, I’m not sure what to take pictures of.

pthomas745 · May 30

We would be looking for your Victron status screens. If your trailer was parked with your battery switch off, the solar was still charging your batteries. After the batteries reached a full charge, the solar has nothing to do. Any type of battery will slowly "self-discharge", but this rate of discharge is usually quite low. So, if the battery is fully charged, and there is no "drain" from the trailer, the solar is off waiting for the "self discharge". If your Victron app on the Solar Controller is saying "Float", that means it is fully charged. (This sort of thing is why it is nice to see the status screens.)

There is one thing missing in your summary: when you turned your battery switch back on, and you were not on shore power, did any of the 12V items in the trailer work? The lights, for example? Or, were the 12V items working?

If you had no 12V at all, find your "Big Circuit Breaker" back there by the battery switch.

This thread explains what to look for.

https://tab-rv.vanillacommunity.com/discussion/15387/battery-power-issue-solved-2021-tab-400-bd

elbolillo · May 30

@floridaman I would suggest taking photos of the Smart Shunt so that we can see how everything is wired together. So photo of the battery install under the bed. Then some close ups of the smart shunt.

elbolillo · May 30

And also a photo of the battery disconnect switch with the fuse that it on the side of it.

floridaman · May 30

Thanks everyone for the comments. We’re on the road without the square bit to remove the panel for the battery under the bed. I checked the battery circuit breaker and is not tripped.

I’ll send pics of the victron screens here tonight.

mjwaldner · May 30

Not sure if this is your problem and I'm not sure what your setup is but if you battery is 100% discharged it might not take a charge because the battery managment system in the battery itself is turned off. When you plug it into shore power the Lithium charge controller might not send power to the battery to start charging because it effectively does not see a battery connected. To bring the battery back to life you need to give it some power just to turn the battery back on. This can be done a number of ways but without knowing what your setup is its hard to say.
See this video for more info. https://www.youtube.com/watch?app=desktop&v=-UjVtaDATMU

Bill&Suze · May 31

If you have a multi-meter that shows ohm resistance, check the 30 amp fuses, one located next to the battery shut-off and the other on the positive solar wire at the solar controller. With the meter's probes on each blade of the fuse, a good fuse should display zero. Of course if the fuse is fully blown you'll easily see it inside its window.

MuttonChops · May 31

floridaman said:
. . . on the road without the square bit to remove the panel

A ) that should be included in your basic TAB Stored Tool Kit

B ) even better, remove those darn screws , , , , they have no function for knowledgeable owners.

Binghi · May 31

I would not permanently remove the Robertson screws holding down the cover over your battery housing. In the event of an accident, the unsecured cover could fly around and cause damage.

PandL_explore · May 31

Two thoughts: (1) If your battery is 100% charged, I believe the solar controller will not allow current to flow from the panel to the battery, so you could be fine except for the app not finding the Victron bluetooth signal intermittently. (2) We also have a 2024 TAB 400. It came with the 310W SolarFlare panel that has had some issues and we are currently seeking warranty approval for replacement through our dealership to NuCamp to SolarFlare (apparently that is the process). Our panel stopped charging in bright sunshine even when we ran the Battleborn 100 Ah lithium battery down below 13.0V. Each morning and sometimes in late evening, the panel starts generating some voltage but not enough to fully recharge the battery before it quits again, either because it gets hotter (and dries out the dew) in the morning or dark in the evening. We can see this behavior day after day in the Victron SmartSolar trends graphs. The battery charges just fine from shore power. I wasn't getting responses from NuCamp tech support about this, but I finally called SolarFlare and got an immediate call back in which the person told me that they had warranty issues with that panel and would replace it, but I needed to work through NuCamp to initiate the process. NuCamp said I need to work through a dealership. It's been a couple of weeks and we're waiting to hear back about the replacement. We are not the only 2024 TAB 400 owners to report this problem. I wish you luck in figuring out what is happening with your system.

elbolillo · May 31

Binghi said:

I would not permanently remove the Robertson screws holding down the cover over your battery housing. In the event of an accident, the unsecured cover could fly around and cause damage.

If you have an accident serious enough to have the cover fly around I think that would be the least of your worries.

Bill&Suze · May 31

PandL_explore said:

Two thoughts: (1) If your battery is 100% charged, I believe the solar controller will not allow current to flow from the panel to the battery, so you could be fine except for the app not finding the Victron bluetooth signal intermittently. (2) We also have a 2024 TAB 400. It came with the 310W SolarFlare panel that has had some issues and we are currently seeking warranty approval for replacement through our dealership to NuCamp to SolarFlare (apparently that is the process). Our panel stopped charging in bright sunshine even when we ran the Battleborn 100 Ah lithium battery down below 13.0V. Each morning and sometimes in late evening, the panel starts generating some voltage but not enough to fully recharge the battery before it quits again, either because it gets hotter (and dries out the dew) in the morning or dark in the evening. We can see this behavior day after day in the Victron SmartSolar trends graphs. The battery charges just fine from shore power. I wasn't getting responses from NuCamp tech support about this, but I finally called SolarFlare and got an immediate call back in which the person told me that they had warranty issues with that panel and would replace it, but I needed to work through NuCamp to initiate the process. NuCamp said I need to work through a dealership. It's been a couple of weeks and we're waiting to hear back about the replacement. We are not the only 2024 TAB 400 owners to report this problem. I wish you luck in figuring out what is happening with your system.

Regarding @PandL_explore's second comment, our 2024 400 BD had exactly the same problem with the SolarFlare panels (we have two.) The dealer's service crew tested them and found them to be practically non-functional (one technician reported that they both "ohmed out"). Prior to that I spent many days trying to test various components and continuously experienced the same limited power generation early and late in the day. The replacement panels have performed flawlessly to date.

floridaman · June 1

here you can see it looks like my solar was delivering power to the batter about 9 days and beyond ago…

pthomas745 · June 1

It does look like your battery was charging...but always in he "Bulk" mode of charging. Which is "ok", but this does point to maybe a Victron SmartSolar not being properly setup to charge a lithium (maybe). But, your battery was getting charged to a decent level.

On days 2, 3, and 4, there was no solar input at all, and the battery levels reached some pretty low levels. Not sure if those day "2" voltage levels would have triggered the Battleborn "low voltage disconnect" or not. (This was mentioned earlier in the thread). Then apparently, yesterday and today, the battery charged on shore power. But, still not seeing the battery reaching a "float" stage.

The only way, really, to try to decode these sorts of things is with a basic multimeter, as mentioned further up in the thread. Is the panel not working? Multimeter on the panel wiring at the controller will tell you.

There are also fuses to check at the solar controller for the solar panel wiring. (Also mentioned earlier). it is also possible that one of the solar panel wires has simply disconnected from the controller.

PandL_explore · June 1

@Bill&Suze, thank you for sharing that you had the same defect problem with your panels. Glad to hear that your dealership was able to test them and help figure this out. With help from @pthomas745 and Andy J, I was able to narrow the problem down to the panels. How long did it take for NuCamp to approve the warranty claim and get the replacement panels to your dealership? Are you willing to share the name of your dealership in case ours in Michigan wants to call yours for advice? NuCamp has been being less responsive than I'd like over this issue.

Bill&Suze · June 1

PandL_explore said:

@Bill&Suze, thank you for sharing that you had the same defect problem with your panels. Glad to hear that your dealership was able to test them and help figure this out. With help from @pthomas745 and Andy J, I was able to narrow the problem down to the panels. How long did it take for NuCamp to approve the warranty claim and get the replacement panels to your dealership? Are you willing to share the name of your dealership in case ours in Michigan wants to call yours for advice? NuCamp has been being less responsive than I'd like over this issue.

Hi @PandL_explore, if I recall correctly our camper was with the dealer for about three, maybe four weeks. The diagnosis was within a day of taking it to them and once they received the new panels, installation probably took maybe 3-4 days. I don't know how long it took nüCamp to approve. I assume that SolarFlare shipped directly to the dealer. As far as I know, there is only one T@B dealer in Maine, located in Bangor - Webb's RV Center, email webbsrv975@gmail.com or phone (877) 806-9292. They sold and have serviced our camper.

PandL_explore · June 1

@Bill&Suze, thank you!! This gives me good information for when we talk to the dealership again tomorrow to get an update. We're going camping while we wait for the panels to arrive at our dealership in Grand Rapids, Michigan.

PandL_explore · June 22

After the SolarFlare 310W panel failed on our 2024 TAB 400 BD, as described above, I called SolarFlare directly on 5/16/25 to find out more about the panel and the rep I talked with acknowledged a "warranty issue" with those panels and assured me that our panel would be replaced without charge.

Short version: On 6/20/25 our dealership replaced the panel in a few hours and we now have a functioning solar panel that recharged our battery!

Longer version, in case this happens to you: NuCamp tech support and warranty units were not very responsive or helpful during the months of April and May while I was trying to figure this out. I resorted to calling SolarFlare on 5/16/25 and that's when I learned about the known issue with the panels NuCamp had installed. The NuCamp customer services unit rep listened, but ultimately told me I had to start with my dealership, which I did on immediately on 5/16/25. The dealership was unaware of any warranty or recall issue with the SolarFlare 310W panels, but they checked into it, submitted a claim to NuCamp on our behalf, and then NuCamp approved it and had a new panel sent to the dealership. When I checked in with the dealership on 6/16, they said the panel had just come in and we were able to make an appointment for 6/20/25 for them to do the replacement. They hadn't done one before, but called us 4 hours after we dropped it off to let us know they were done. The technician's report on the replacement indicated that removing the adhesive was a challenge and that it took more time than NuCamp had allotted for their work. As promised, though, the dealership did not charge us anything at all. We first noticed the problems with the panel not providing power (except minimally when damp and cool early in the morning or sometimes late in the evening) in early April. We learned a lot about troubleshooting from you all, including @pthomas745 and heard similar stories from two other 2024 TAB 400 owners, including @Bill&Suze. We went camping a couple of times during the nearly 3 month saga, using shore power for one trip and being super careful with our electrical use on the other (lights and water pump but no refrigerator use). We still love our TAB400 and are delighted to have it fully functional again!

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24 T@B 400 Intermittent 12V Power Issue

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