Lights flicker when AC is plugged in

Hello, I am new to this site, but in need of help.  I have a 3yr old coleman pop up with a Centurion 3000 series converter. When I hook up AC power the lights flicker and the overload dummy light is illuminated. Coming from the converter I have 3 blue wires and 1 red wire all with 13.4v, I also have one white wire (Battery and DC Negative). When I hook up AC and disconnect the battery I get a good 13.4v leading to the battery, but as soon as I connect the battery My lights start flickering again. I have tried unplugging everything in the pop up (Furnace, lights, Fridge, water pump, and DC outlet) but I still get the same results.

Is my converter bad, or do I have a short somewhere???

If the lights flicker with the battery connected but not when it is offline, I would suspect the battery is bad, perhaps shorted internally.

The battery is only 1month old. Also when the AC is connected and the battery is disconnected I still have flickering lights, but I thought the battery had to be hooked up for the lights to work anyway. The service guys out here told me that the 12v ckt had to be complete and that the battery had to be hooked up for the lights to work. I never tried it without the battery when it was operational.

Also when the AC is connected and the battery is disconnected I still have flickering lights

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I assume you mean that when you are plugged into shore AC power the lights flicker. Shore power is what powers your charger and the lights are still running off the 12v system, i.e. being fed by the charger and battery. Plugging into shore power does not "disconnect" the battery in any sense.

What happens when the battery is in the circuit and there is no shore power? Lights work without flickering? Are they nice and bright or do they dim fairly quickly? If you have a short, it should drain the battery fairly quickly and the lights should begin to dim. And check the battery voltage with shore power disconnected and lights on, fridge running, etc. It should stay up around 12.6V for a t least a few hours if the battery is good and fully charged.

You could also disconnect the Centurion from the battery and hook up another battery charger to it and see if the flickering goes away. Any 12v battery charger will do. If the other charger does not shut itself off (usually what happens on a short) and there is no flickering, then your Centurion is suspect.

The 12v circuit does need to be complete but it can be complete without actually having the battery online. Just hook the 12v feed from the charger direct to the trailer's 12V wiring and leave the battery out of it.

You mentioned an "overload dummy light", but I am not sure what that is. Some kind of indicator light that says you have an electrical overload? From what I can determine, the Centurion boasts an automatic reset when a short circuit is detected. This could produce flicering if the circuit is continually opening and resetting. The short could be a very low resistance in the battery (even though it is only 1 month old) or somewehere in the 12v electrical system.  Try unplugging the 12v fuses one at a time to see if one of them stops the flickering. Or is that what you meant by "unplugging everything"?

I have 4 DC fuses and I tried unplugging them one at a time. The only difference is on the battery protector fuse, when unplugged the lights get very dim with a lot of noise. When the AC is disconnected the lights are bright. right now I have all three lights on and the fridge. I have a steady 12.16 on my battery. It has been steady for 15min. I will monitor for a couple of hours or so. I do not have another battery charger. Is there any other way to complete the 12v ckt so I can have the battery disconnected and run off AC only (through the converter)???

I just took a battery out of my truck that was 12.4v and tried it on the camper. Same results, no luck, I am stummped.

With some small converters if the battery is run down the converter has not enough "oomph" to charge it.  This will give you exactly the results you see.  The solution is to find another way to charge the battery, then load test the battery

Also.. I somewhat strongly suspect you might have hooked up the battery..... Backwards

NOTE: Suspect means just that.  So check to insure you have hooked the battery up properly


Make sure the NEGATIVE battery lead is the one that goes to the chassis.

I have a steady 12.16 on my battery. It has been steady for 15min.

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To me that indicates a battery that is only about 50% charged. Not good.  A few lights for 15 minutes should still leave the battery at 12.6V.

I'm not sure what you mean by a "battery protector fuse", but it seems to be the one that isolates the problem circuit.  Exactly what does it disconnect when you remove this fuse?  If it is the fuse that disconnects the charger from the battery, then the battery is indeed bad. But if it disconnects the battery itself from the trailer power circuit, I'm not sure what to think.  You may need someone with a good working knowledge of 12v power systems and electrical test procedures.

John I did check the battery connection and the leads are set up correct. Also I did hook the battery up to my truck (via jumper cables) and let it charge for 3hrs, same results in the end.

There is a resistor (looks like to me) close to the battery, probably so the battery does not get overcharged, that I have not checked out. I am thinking today after work that I will bypass this resitor by disconnecting the battery and running a lead from the camper to the battery only for a short time.  What do you think????

I am assumming I do not have a short in the DC wiring because when hooked up to battery only everything works properly.  Is this correct?

I have contacted the RV service department here locally and they told me that there is a ckt breaker attached to the battery to prevent a power surge from the battery. I will try to bypass this and see.

Also the service department could not tell me if the lights should work when plugged into AC with the battery disconnected.

Can anyone tell me this:  When I have the battery disconnected and AC plugged in, should my converter run my lights and DC powered equipment?

Yes, your converter should run all the DC accessories without a battery present, but if the output voltage is high, it could shorten the life of any bulbs.  The battery acts as a sink to keep the voltage at the proper level.

What you call a resistor is probably a high amperage fuse.

There should be no resistor near the battery.. There may, however be a small metal case (or a somewhat larger plastic case) with two posts that have wires attached,  One runs to the battery,, One to everything else

This is a self-resetting circuit breaker and you should NOT, Ever bypass it.

Ned said:

Yes, your converter should run all the DC accessories without a battery present, but if the output voltage is high, it could shorten the life of any bulbs.  The battery acts as a sink to keep the voltage at the proper level.

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In my case with the battery disconnected and AC plugged in the ac accessories do not work properly, but with the battery connected and the AC disconnected the DC accessories work fine. Would this mean that the converter is faulty? or Could I still have a short somewhere (even though the DC works off battery only)?

If the lights continuiously flicker when plugged into AC I would suspect your converter is at fault and is letting the AC 60 cycle ripple through due to poor filtering.

I agree with the last post but not for the same reason.  The battery itself should provide adequate filtering and you don't see flickering in house bulbs and they work off 60 cycle AC.

I would think that your Converter is cycling between charging and not charging which says that its internal voltage sensor is faulty.

Thank you so much everyone for the help. It makes sense to me that the converter is cycling between charging and not charging. This is why I am seeing DC voltage on the outputs, but as soon as I connect to AC the lights flash, hence the cycling. I am placing an order for a new converter now and will update the posting when installed.

I think the whole time I just needed some reassurance before spending and extra $110.

Although I am a newcomer to the forum, I will continue to be an active member because of the friendly people.

Hope the new converter fixes the problem.  Looking forward to hearing the results.

Re; No filtering on converter causing "Flicker" Your eyes should not be able to see 60Hz flicker but... Some can

One problem I have with this thread is the word "Flicker"  I assume you mean they get bright/dim/bright/dim. but how fast

Very rapid, every 3 seconds, every 2 minutes.  Flicker means something to me (Roughly 1 to 50 HZ) anything slower I'd call "Blink" but .... I do realse that the word Flicker can mean every few seconds or even longer.

In my case "flicker" means about every 2 sec, bright to dim to bright.

Yesterday before ordering a new converter I put my meter on the battery and plugged in the AC. I found the voltage fluctuating between 12.3 - 12.6 off and on, in sync with the lights flickering. To me I am assuming that when the converter is placed on DC load the converter is indeed cycling between charging and not charging. When there is no load the DC voltage is a steady 13.3v.

There is no doubt in my mind that the flicker is caused by the charger cycling on/off, but I remain unsure that the converter/charger itself is bad.  It is designed to shut itself off if there is a current overload (aka "short" or if the voltage goes too high or too low.  The thing that makes me most suspicious is that your battery voltage is too low - you say it varies from 12.3-12.6V with the charger on.  It should be in the 13.6V range. That indicates the charger is not able to produce sufficient charging current/voltage and suggests  ahigh current load somewhere in the trailer (not necessarily a direct short to ground), a corroded connection (high resistance to charging) or a bad battery. And yes, a one month old battery can be bad.  Of course,  defective charging control circuitry in the charger could produce the same results.

If you are confident you have ruled out the other possibilities, pay the $$ for a new converter/charger. But to me the evidence is not conclusive.