Monday, February 6, 2023


Dim interior lights: Battery problem or power converter?

By Steve Savage, Mobility RV Service

Here’s a common question that’s worth sharing.

From a reader: Recently my lights in my fifth wheel have started getting dim and sometimes flickering. How can I determine whether my problem is a four-year-old battery or the charger or the converter? I have disconnected my negative battery post while plugged into campground service.

When I disconnected the negative (battery cable) and checked my lights, they were very bright for about two minutes and then went dim. Then I turned on another light switch and they went bright again for a few minutes. How can I check the battery charger? I have a meter to check it, but I don’t know the procedure to check it.

My response: Very simple! Connect your battery and test the voltage with your meter. If you don’t see over 13 volts, your converter is dying. Any time a power converter is plugged in and working, you will always “see” more than 13 volts. The power converter is also the only thing that can make your 12-volt lights flicker, provided your AC power is good. That is to say, as long as you have good power at your receptacles and at your microwave, your power converter is the only possible villain.

It is not unusual that power converters become erratic before they fail completely. The battery is not relevant with an operational converter because it can easily carry the lighting load. You could have a completely dead battery and still have good lights.

You can temporarily work around this by putting a regular battery charger on your batteries, but you need a new power converter. I am not clear why you are using the terms “charger” and “converter.” You have a power converter that converts 120 volts AC to 12 volts DC, and that charges the battery. It also supplies 12-volt power to your lights, etc. The remainder of the panel is called the distribution panel. You either have a distribution panel with the converter built in, or you have a distribution panel with the converter mounted separately and tied to the panel with a red (+) and a white (-) wire.


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Larry Swisher
1 year ago

2016 nitro XLR, garage lights only started flickering from time to time now they are very very dim 🤷. Not sure where to even start looking

Katheryn Kerr
2 years ago

We are plugged into electric box or shore power I guess you call it, anyways recently when using our little conventional oven the lights flicker and a buzzing/electrical sound comes from the fuse panel also a couple of times while running the overhead AC units they have loss of power intermittently, but only a couple of times. I am deathly afraid of any type of electricity but I did manage to tighten all fuses but that didn’t help any. There is a couple of wires that seem to possibly be touching, would that cause this issue? Or does it sound like my converter is going out? Oh, and I do have a multimeter but do not have a clue how to use it, can you give me a link that SHOWS me how, I’m better hands on than anything. My RV is old but in good condition it’s a 1985 Southwind Fleetwood, I’m very RV illiterate and am now living in this thing. Lol

Mike Sokol
2 years ago
Reply to  Katheryn Kerr

I have tons of articles that show how to measure various things. Here’s a good basic one on meter usage:

3 years ago

This looks similar to my problem. I am living in a travel trailer and do not use it for travel. It is a wildwood lite with a Texas 2004 license plate on it parked in Mississippi. My uncle helped me get it and told me, “if you need anything, give me a holler.” Then he died a few months later. Most of the things in my trailer do not work now or I don’t know how to use them such as the gas oven, but I still have cold water. Things went out one by one like the microwave or the electrical outlets. Lately the lights have gone out and sometimes I can hear bleeping as the bathroom lights come on and off in time with the the rhythmic bleeping noise. I can no longer read after dark. I have to come home, find the bed and go to sleep until morning. I know where the fuse box is located, and there is something on a post in the back yard that I ought to look at. I am sorry that I do not have the vocabulary to tell you whatever questions you are sure to ask.

Katheryn Kerr
2 years ago
Reply to  Annette

This is so sad, I’m so sorry, did you ever get your issues in your RV fixed or find another place to live? I sure hope your in a better situation now. I wish I could help, but I’m pretty much like you, having electrical issues (although not nearly as bad as yours) and don’t have a clue on how this and that work. We bought this RV without knowing the first thing about the way things work, or anything having to do with batteries, electricity, any of it pretty much.

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