Need advice on why interior lights dim periodically.

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MN Blue Skies

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The lights in our 5th wheel periodically dim. It happens every few minutes. What do you think the problem is? TIA.
 

Kirk

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If you are connected to shore powerit is probably the converter. RV lighting is 12V and the dimming is probably a voltage drop. That can be an indication of a battery issue, or it could be some other 12V load that cycles on and off.
 

Ray-IN

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I agree with Kirk. A marine battery is a dual-purpose battery for engine starting plus powering a trolling motor, lighting when anchored, etc.
The battery might be low on liquid, if you can see the plates inside, add distilled water up to the split-ring in each battery cell, not over though. Wear eye protection when adding water, a splash of battery acid can blind a person.
You really need a deep-cycle battery, they will not list a starting amp number like a marine battery.
 

Ex-Calif

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The lights in our 5th wheel periodically dim. It happens every few minutes. What do you think the problem is? TIA.

LED lights or incandescent? If the lights are dimming on a cycle then it appears voltage is dropping on a cycle. Do you have any 12V equipment operating on a cycle, Fridge come to mind but the controller should be a steady draw.

Can you correlate the dimming to any other equipment cycling?

Do you have any indicators of battery voltage in your rig? A cheap USB or cigarette lighter voltage indicator would give some idea of your voltages.

I have a 400W inverter wired in that gives a continuous read out of battery voltage.
 

Gary RV_Wizard

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The most common cause is a battery in poor condition (see Kirk's reply). The converter/charger keeps trying to bring the charge up but the current (amp) draw is excessive, causing a drop in power available to operate lights and such. It's also possible that some other 12v device cycles on and draws a lot of power, but most RVs don't have any high-amp 12vdc devices.

A 3 year old marine battery is probably nearing its end of life unless you have been really scrupulous in care & use.
 

MN Blue Skies

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I
The most common cause is a battery in poor condition (see Kirk's reply). The converter/charger keeps trying to bring the charge up but the current (amp) draw is excessive, causing a drop in power available to operate lights and such. It's also possible that some other 12v device cycles on and draws a lot of power, but most RVs don't have any high-amp 12vdc devices.

A 3 year old marine battery is probably nearing its end of life unless you have been really scrupulous in care & use.
I don't think we have any high amp devices that would be drawing a lot of power. There doesn't seem to be any rhyme or reason/pattern for the lights to dim. The battery might just be the culprit. I will discuss with DH.
 

Krazeehorse33

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Check to make sure the battery connections are clean as well. I agree the battery may be tanking but it doesn’t take much corrosion to affect the charging and output on the battery.
 

DonTom

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The lights in our 5th wheel periodically dim. It happens every few minutes. What do you think the problem is? TIA.
I had that problem big time in my new 2022 RV. In my case, it was a loose fuse socket for the blade fuse that ran all the LEDs interior lights. A one-minute repair job.

-Don- Auburn, CA
 

John From Detroit

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Davison Michigan
What converter do you have.
There are only two or 3 reasons the lights would dim
Either the converter is cutting out from time to time (This may be due to external things.. or not)
Or the load on the system is cycling.. This too can happen in an RV

The 3rd one is .. Well I'm not sure
If one of the batteries is dead on a motor home (This would NOT apply to trailers) and the Isolator is a B.I.R.D. type (Bidirectional Isolator Relay Device)
Then as the isolator will cut in and out to help the weak/dead battery. If the chassis battery is the low one then when it engages lights dim. if the house. when it disengages lights dim (it should never engage however if the house battery has a shorted cell)
 

MN Blue Skies

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Unfortunately the 5th wheel is now parked in an offsite/outdoor parking space for the MN winter. No access to electric. Hmm... we're hoping to leave MN in January. I'm optomistic that we can make that happen one way or another.
 

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