Intermittent loss of power

BWidget

2015 T@B 320  Outback.

Recently I am having intermittent loss of power while plugged into shore power. I've had this happen at a campground and at home, with and without a surge protector inline.

I know this is happening because if I have the radio on it will go 'dead' for a second and then come back on.

When I have the AC and the radio and ceiling fan on when the power cuts out the AC keeps running but the radio and ceiling fan do not.

I could not see any loose connection in the wiring that is under the driver side well, where the power comes in.

I just replaced the main 3015 circuit breaker to try to fix the issue but that was not it.

Any suggestions.

Thanks

ScottG

The A/C runs exclusively on 120VAC directly from shore power. The radio and fan run on 12VDC from the converter (which is in turn powered by 120VAC shore power).

Therefore, the symptoms you describe suggest the shore power connections are okay, but the converter is cutting out for some reason. What that reason might be is out of my pay grade, but at least this may help narrow down the possible culprits.

Grumpy_G

Assuming the trailer has a working battery a simple dropout of the converter would not cause the 12V appliances to go dead. If the converter or anything else for that matter creates a huge power draw through e.g. a short there would be smoke signals and/or blown fuses. 
I'd still have a closer look at the fuse box and the wiring on the 12V side, specifically at the connections to the PCB that carries the fuses. Disconnect 120V before removing the front cover. 

MuttonChops

@BWidget ;  I agree with @ScottG comments that your issue has something to do with the Power Center Convertor Section.  If the Convertor itself is OK then a possible intermittent open/short in your T@B wiring.  An Open being more likely than a short as shorts tend to be non-intermittent since something has melted or otherwise been joined together.

With your Battery Cut-Off switch in the ON or OFF position an intermittent DC Ground Connection might cause the symptoms.
  - - Check your Ground Bus Bar located behind the Power Center on floor.
        Confirm all wires are nice and tight.
  - - Also confirm screws without wires are tight . . . one may contact trailer chassis ground.

If the problem continues after checking the ground bus bar then the Power Center could be detecting a really weird trailer wiring issue or more likely is starting to fail with it's internal protection circuits falsely tripping.

Am not sure how to troubleshoot that type of failure mode. Perhaps sitting in T@B watching/listening to Power Center might indicate something; fan quick cycles, heat on face plate, ? ? ?
Yes, this is unlikely to provide useful information but no harm in trying.

Some of the 8700 Series protection features from WFCO web-site manual.

BWidget

I did an initial check of the wires on the Ground Bus Bar, I will double check.

I do not have a battery cut-off switch. The batteries though are disconnected from the terminal while at home. I believe they were connected while in the campground.

BWidget

Another note, before this started happening the 2 6v batteries were good, and now they are dead. Not sure if there is any correlation. I drive with the batteries connected then when I store the trailer I disconnect all connections at the terminals.

ScottG

Grumpy_G said:

Assuming the trailer has a working battery a simple dropout of the converter would not cause the 12V appliances to go dead. If the converter or anything else for that matter creates a huge power draw through e.g. a short there would be smoke signals and/or blown fuses. 
...

Duh. Good point @Grumpy_G! I retract my previous diagnosis and agree its probably a loose connection on one DC leg or the other.

However, if that were the case it seems the problem would occur when running on battery as well as shore power. Have you noticed it when running on battery alone?

BWidget

Dead batteries now, but I do think I first noticed it while camping on batteries.

I'll hook it up to my vehicle and see what that does.

MuttonChops

BWidget said:

. . . before this started happening the 2 6v batteries were good, and now they are dead.

Well that makes me think the Convertor is dead.
While you were on shore power with the A/C running the convertor should have been charging your batteries but clearly it did not.  The intermittent operation of DC powered items could be indirectly related to dropping battery voltage since the convertor may not be generating any 12VDC.

There is a troubleshooting method to test the convertor output.
It requires removing fuses and probing Power Center panel with a voltage meter.
Any RV shop would be able to do the test if it were beyond your comfort level.

ScottG

Curiouser and curiouser.

I like the idea of checking things while hooked up to your tow vehicle. I suggest doing so with both the battery and shore power disconnected--this will ensure that the tow vehicle is the only source of power (assuming your tow vehicle trailer connector is equipped with a 12V charge line).

I also suggest checking things while hooked to shore power but with the battery (and tow vehicle) disconnected--this will ensure that the converter is the only source of power.

If you isolate each 12V power source (shore power/converter vs. battery vs. tow vehicle) and find the problem occurs in all cases, that would suggest an intermittent loose connection in the 12VDC distribution system. If the problem occurs in some cases but not others, that could point back to the converter as @MuttonChops described.

Please keep us updated as to what you find. 

BWidget

Running strictly hooked up to my tow vehicle (no shore power and no batteries) I did not notice any interruption in power. I only did about two 15 minute tests but under shore power only in that time frame I would have had issues.

I won't be able to get a new power cord or battery for about a week, that's when my new trailer arrives and I will have those items.

So it looks like it is pointing to the converter.

ScottG

If you are getting a new battery I presume your old one is toast and won't take or hold a charge. I wonder if your battery was so depleted it was taxing the converter and causing it to cut out because of the over-temp protection feature @MuttonChops mentioned in his first post.

If that were the case, a new battery might solve the problem. Fingers crossed!

BWidget

My latest test with shore power was with the batteries disconnected. I am seeing a bulge in one of the batteries so I assume it will not be any good.

ScottG

So what were the results of that test? Did the problem occur when the battery was not connected?

BWidget

No finite resolution as I sold my trailer as-is. I was trying to fix this before I sold it but I got a good price.

Thanks for everyone's help.