Self Re-setting CB Problem

[coachmanrvr]

During my last night out on our Michigan Trip we started hearing an odd noise from the battery compartment. Upon inspection we found that the self re-setting CB on the converter/battery charger kept opening, then resetting only to repeat the cycle. Unplugging the converter stopped the issue and the coach ran fine on just batteries. (So I would think the batteries are ok)

Turning off the coach disconnect and plugging in the converter again worked no problem. The coach will run on the converter if plugged into AC even with the battery disconnect off. (So now I assume the converter is ok?)

The pic has a vertical brass bar. The converter is connected on the top right connection to the bar through the re-setting CB.

Any ideas?

[Mike Canter]

Well that self resetting CB is doing what it is doing because something is drawing too much current through it.I would suspect a bad battery, maybe shorted out inside the battery. If the inverter/charger works OK without the batteries connected but not with the batteries connected then there is a problem. The coach may run off just the batteries but is the battery voltage up around 13+ volts or is it running down fast?

[coachmanrvr]

The batteries read 12.9 volts with the converter unplugged. Turning on some lights in the RV draws it down a bit, but the batteries seem to hold just fine.

[Mike Canter]

Still something causing excess current draw. What about the chassis batteries?

[coachmanrvr]

Chassis battery seems all good as well. Starts right up with no issues.

[nodine]

Quote:

Originally Posted by coachmanrvr Chassis battery seems all good as well. Starts right up with no issues.

As Mike has pointed out I would suspect that the battery bank is requiring too much current when charging or that the circuit breaker has gone bad. If you are skilled in this kind of stuff, use a DC current measuring device that has a range higher than the circuit breaker and see how much current is flowing in the line. One other trick you could try is to disconnect one battery in the bank and see if the breaker holds.

Bob

[coachmanrvr]

I would love to be able to measure the current, but don't have a DC device that can carry the 50 amp rating on the CB. AC is easy with an induction type meter....DC, the only way I know is in line.

The battery bank is two 6 volts in series. No way to test each one. I guess I am down to either replacing the batteries, CB, or the converter. Got to be one of the three.

[Mike Canter]

Take the batteries out and take to a battery place like Sears or Interstate Batteries and have them tested.

[coachmanrvr]

That's a good idea. Can they check 6 volt batteries?

[coachmanrvr]

Talked to the techs at Monaco and together believe the 50amp self-resetting CB is bad. Would you believe that the local O'Reillys has self resetting CBs in stock! They did not have the 50, so I bought a 30amp to just try it. (3.99 each I figured why not?) Swapped it out and so far it is good. We plan to go out in the garage and watch a movie in the RV tonight to make sure the fix is ok. We plan to put some more miles on it this weekend and then know for sure.

[coachmanrvr]

Put the 50 amp CB in place tonight. It seems a solid fix. Fellow UFO'ers, put this one away, cause I'll bet it will be there for you guys soon. Three dollar and 99 cent fix. Easy!