? electrical problem...what’s happening? Should I worry?

Either failed battery or converter is bad.

kabbro wrote:
Oops, thought of another question: if when I take the battery into a battery shop and they test it and if they say it’s “good”, then presumably the problem would be a failing converter?

Yes.

If you have a voltmeter you could find out right now by looking for 13.6 volts on the battery or to the cable if you disconnect a battery cable.

Is the battery warm and bubbling?

If you have a 10+ amp portable battery charger you could bring it along to use in place of the converter depending on the time you have to get this sorted out.

Oops, thought of another question: if when I take the battery into a battery shop and they test it and if they say it’s “good”, then presumably the problem would be a failing converter?

Thanks, appreciate the help that always comes from you folks. Right now I had to take the trailer back into storage but will definitely take the battery out and have it checked. I admittedly don’t know much about RV electrical systems. I always though that when the RV was plugged into shore power that “overrode” the 12 volt system and lights were working on shore power. So, if the battery were disconnected or removed, there would be no overhead lighting even though connected to shore power? 2nd question: the RV had been hooked up to shore power for 3 or 4 days prior to this event...I believe I heard the converter working a time or two while in and out of the trailer...that should be charging the battery, right, unless the battery is failing and won’t “take” a charge. Right? 3rd question: when the lights faded and then came back on, was it because the battery was “taking” somewhat of a charge but not holding it? 4th and last question: if I hadn’t had to take the RV out of the driveway and back into storage and had left the lights on, the battery would have almost completely lost its charge and the lights and everything else 12 volt would have failed/faded, right (of course I realize that that would happen also with a “good” battery, but not as fast. Actually the week before I brought the trailer home I had done some interior work while trailer was inside the storage building and I was pleasantly surprised at how well things worked on 12 volt power while I did the work...I was sort of expecting to run out of battery power over there but didn’t.

Lights work off the 12 volt DC system. When connected to shore power, lights and other 12 volt DC devices work off the converter. While this is happening the converter is trying to charge the battery(ies).
I am thinking you have a failing battery that the converter sends power to charge it, but can't.
Post make and model of converterz
Have battery charged and have it tested as suggested in earlier post.

Lights are connected to the batteries so I'd start by having them load checked.