Interior Lights dimming

[Jersey Camper]

When I am plugged into city electric my interior coach light get dim and then brighten every fifteen minutes or so. I cleaned the battery and electric 30amp terminals and plugs. I also put a load test on battery with a meter and dc volts were good. I am thinking maybe a problem with invertor/convertor..Is there a way to test it and hoe big of a job to change it

[Paul R. Haller]

Disconnect the positive wire from the converter to the battery or fuse panel and measure voltage at the converter with the trailer plugged into shore power and the battery out of the circuit. It should read about 13.5 volts. What kind of converter do you have? Leave the meter on and read it to see if the converter is bouncing voltage. Normally, unless the converter is overheated or something else is wrong, you do not get output voltages bouncing like you suggest. What about the shore power? Is it bouncing?
-Paul R. Haller

[Jersey Camper]

I have a WFCO 45 amp converter, Its a combo converter and charger. The shore power seems steady

[Jim Stewart]

That Inverter/Charger senses voltage every time you apply a load. This could be the 12 volt supply to the refrigerator or air conditioners switching on. If the voltage is below 13.2 volts, it goes into the bulk charge mode (14.4 volts) Your batteries could be dropping below the 13.2 volts and you are seeing the reduction momentarily when it switches to the bulk charging mode. The bulk charging mode drops back when it hits 13.6 volts and goes into the absorption mode (13.6 volts).

Don't know if this is it or not, but would make sense, you could have weak batteries that are dropping voltage quickly.

[Paul R. Haller]

Contact WFCO either by looking them up on the web or call and ask specs on your unit. Talk to Customer Service and be sure to back up your concerns with facts as witnessed by volt meter readings. See if this is a multi stage or single stage unit and check batteries. Ask their opinion. Good luck, and keep us posted.
-Paul R. Haller-

[FiverBob]

You gave us no model number on your converter, but I noticed on their website even their small 35a charger is a three stage charger. It is rated at 13.2, 13.6 and 14.4 volts for the various charging stages. My gut feeling is you are noticing the difference in the lights when the voltage kicks up when needed by the batteries. You are obviously charging and by your figures not overcharging. I don't think you have anything to worry about unless when you say the lights are "dimming" you mean "really" getting dim.

Bob