Question concerning power converter

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Rick Brooks

New member
Joined
Apr 9, 2013
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3
I have a question concerning the power converter in my 2006 KZ.  Sometimnes when we got to a park and hook up to the 30 amp electric power there.  I have noticed that the 12 volt overhead lights are really dim, and that when the convertor starts they begin to brighten quite a bit.  Also the convertor will run for 20 to 45 seconds then cuts off and the lights after a few minutes will begin to dim.

I replaced the battery with a new one but this problem still exists.

Is my convertor going out or is this just something that is supposed to happen?

Any help will be greatly appreciated. 
 
Hi Rick, welcome to The RV Forum!

No, having the lights get bright and dim is not supposed to happen.  It certainly sounds like the converter is overheating and shutting down.  Can you find the make and model number of the existing converter?

There are a couple of long shots you can check before condemning the existing converter. 

Make sure the cooling fan comes on before the converter shuts down.  Most fans are thermostatically controlled and if it doesn't start the converter will overheat and shut down until it cools off.  Also make sure there isn't a bunch of dirt and dust blocking the fan and cooling fins. 

And look for a self resetting circuit breaker between the converter and battery.  It looks like a small metal tin with two metal posts on top where the wires connect to it.  The breaker uses a bimetallic element that heats up and opens a set of contacts when excessive current flows through it, then it resets in a few minutes when the element cools down.  After it trips a few times the contacts become worn and add additional heat, making it trip at a lower current.
 
I would also look for a bad, e.g. corroded, wire connection between battery and converter and (if different) battery and 12v power distribution panel. High resistance in the connection can fool the converter and give odd effects like you are seeing. Sometimes a battery cable is bad between the wire itself and the connector on the end, inside where you can't see it.
 
The running for a short time then it dims, and does it brighten back up in a bit? and then perhaps dim again,, then finally, after a few cycles it gets bright and stays bright?

That would be an overloaded self-resetting thermal circuit breaker.

NOW...... This may be indicative of an aging breaker that no longer passes it's full rating.

Or it may be an indication that you've upgraded the battery bank to a larger size and they are so low that they are sucking more than the system can provide, so the breaker is working as designed.

i'd consider replacign the breaker.

BUT... Before you do that.. If you have a Surge Protector (And you should) plug in something 120vac and see if it "Blinks" as well, a simple night light will work,, Or a simple neon night light ..(like 5.00 each or less) plug it into a NON INVERTER powered outlet or a voltage monitor (IE: Kill-a-watt meter on Volts) and see if the 120vac is "Blinking"

If so.. Let us know and folks will advise how to "Fix".
 
Thanks for all of the input.  I still have a warranty on my trailer so I think I will take it to the dealer and have them check it out.  With the luck I have I would probably electrocute myself or burn the thing down to the frame. 
 
Gary RV Roamer said:
I would also look for a bad, e.g. corroded, wire connection between battery and converter and (if different) battery and 12v power distribution panel. High resistance in the connection can fool the converter and give odd effects like you are seeing. Sometimes a battery cable is bad between the wire itself and the connector on the end, inside where you can't see it.
I'm with Gary....... Sounds like all is well until the converter "Thinks" that the battery is at full charge. The converter goes to float mode and the battery can't keep up with the needs and shortly, the converter "Thinks" that the battery is low and kicks on again.

One quick test would be to disconnect the battery and see if it still does it. If that clears up the problem there is probably a dirty connection or even a bad wire somewhere. I had a trailer one time that drove me crazy until I replaced the entire wire between the battery and converter. I took a razor blade and cut the insulation the full length of the old wire. The wire was shiny bright copper all but one small place. There was about 1" that was all black (right in the mid-point of the wire). When I bent the wire, it just crumbled. The insulation was not even discolored.
 
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