Lightbulb problems: fixture or wiring?

OK, I'm going to chalk this up to being more than just one fixture.

I was sitting around last night with just the fixture over the table on; which is not something that normally happens.

It started getting dimmer in a cycle that ran maybe about 5 minutes? (I did not time it.) The bulb would be normal brightness for several minutes, then get dimmer for may 10 seconds, go back to bright, wash, rinse, repeat. During the cycles the bulb never got brighter than normal.

So, one fixture burning LEDs in a reproducible pattern and another fixture (maybe on the same circuit?) getting dimmer, but not brighter, in cycles. Where do I start looking for that?

I have not noticed all my bulbs getting brighter or dimmer at the same time.

Right now we are perma-parked and always on shore power unless it is down.

I have a solar system that includes a smart charger / battery tender.

I have had this happen while parked at two different RV parks.

I do use cheap bulbs, but the same cheap bulbs are working fine in the other fixtures.

@RoyB: I'm just barely getting my toe wet for the first time in my life with anything to do with electricity. I can only guess that you sound like you know what you're talking about. But, it's all greek to me. So, once again a little more slowly please?

The LED Assy has a DC VOLTAGE specification. Some LED's are operated with a small range of DC Voltage. I have some ceiling LEDs that operate in the 12-14VDC range...

If the LED ASSY has a built-in regulator then this range can be extended over a wider range... I used to have a LED ASSY that operated from 9-30VDC range...

You need to find out what range your LED ASSYs are specified for and then measure the operating voltage to see what it reads for this location...

I am only discussing a 12VDC LED specification.... LED's can also be a 120VAC unit...

I guess another question for is do you ever see all of the LED lights getting brighter and dimmer sometimes. this could be traced to your converter/charger unit may be starting to go bad for you... This could also be related to a battery going bad on you and being charged at a higher than normal DC Current causing the converter/charger working very hard trying to keep the battery charged up... This could be determined if you have lost any battery fluids which is a common failure sometime associated with a single mode converter/charger unit that only puts out 13.6VDC.

Need to do some DC voltage measurements..

In my trailer setup my battery DC volatge without being conncted to shore power will read from 12.0VDC to 12.6-7VDC depending from its charge state.

When on shore power my on-board converter/charger will only produce 14.4VDC-13.6VDC-13.2VDC smart mode charging levels.

As you can see with this my 12V operating range is only 12.0VDC to 14.4VDC. There is no other source in my trailer setup that will produce any higher DC voltage under normal operating conditions.

Both the converter/charger 12VDC output and the Battery 12VDC output feed the same point on the 12V Distribution Panel so that your trailer can operate from both shore Power connections or off the Battery when OFF-GRID...

Roy Ken

I would check the socket and the connections to it, making sure they are making good solid contact. My initial gut feeling is that this may be heat-induced, and a poor connection at the socket would cause localized heating. (My second thought is that it might be moisture related particularly if the LED bulbs are cheap quality ones, since this is over a sink.)

Since this is the only light doing this, and I assume the same sorts of bulbs are used elsewhere in the RV, I would tend to suspect it's not something more general with the RV electrical system.

Electrical ghosts are sometimes hard to figure. Have you opened the power converter to look for bad connections. Be sure to disconnect 110 power and the battery.