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

[kabbro]

I am prepping and cleaning travel travel for upcoming trip...had the unit plugged into my 30amp connection at home, was inside with only the air conditioner running and 3 overhead lights in trailer on...suddenly the output in the lights decreased to about 25% of normal output, stayed that way for maybe 15 to 20 seconds and then gradually reverted back to normal.....about 5 minutes later the same thing happened, again reverting back to normal output. When this occurred the ac was running steadily, hadn’t just turned on or cycled or anything (at home when the air kicks in I can often see a minimal sudden lowering of light for a fraction of less than a second)...my wife said nothing was going on in the main household electrical input or output.

I would appreciate any ideas about what may be occurring and whether this needs to be pursued further at this time (probably won’t be using the air on trip, though not certain this has to do with ac....have used ac a lot with this never happening before)

Thank you for any help.

[theoldwizard1]

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, and that is my first guess.

[enblethen]

Age, Make and model of converter when you can get it.

[wa8yxm]

Ok the lights going DIM then brightening back up suggests something is drawing one HECK of a lot of 12 volts.
One possibility is bad batteries (They suck the converter down) as suggested up in fact I'd rate 'em high on the list and there are often self-resetting thermal breakers in the main battery line. along with other types that you need to manually reset depending on the RV.

It is also possible something else is sucking 'em down.

[DrewE]

Besides the batteries and the converter, the problem could simply be a bad connection or wire (usually where it connects), causing a high impedance connection between the lights and the 12V power source. Make sure the cables at the battery are all in good shape and the ends clean where they connect, and the ground connections are likewise sound where they connect to the frame.

This is fairly easy to check, actually, beyond a visual inspection. If you measure the voltage at the battery terminals themselves, and it stays (nearly) the same while the lights are changing in brightness significantly, then clearly there is a difference in voltage between the battery and the rest of the system, indicative of a poor connection somewhere between them.

[TurnThePage]

Something similar to these two items would keep you pretty well in the know about your current power situation.

12 volt plug in gauge

Kill-a-watt meter

And while you're at it, get one of these and keep it plugged into the Kill-a-watt.

Circuit tester

[3_tons]

If plugged in to shore power, then repeat this same scenario, but this time around (after first verifying batts are good) with the converter breaker switched to OFF…

3 tons

[bgum]

Either failed battery or converter is bad.

[time2roll]

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.

[kabbro]

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?

[kabbro]

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.

[enblethen]

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.

[CA_Traveler]

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