Electric issue has me baffled

[blrdck]

30 amp travel trailer without an inverter, converter only.  Plugged up to 30 amp pedistal which checks out fine. Slide would not come out (12 volt DC), A/C would not work, 1/2 the 120 AC outlets not working. Two 15 amp circuit breakers. One trips. A/C breaker does not trip but A/C won't run. I looked at dead outlet connections and saw no issues. GFI not tripped. Battery is dead. I go buy a new battery, install it and everything now works. How could a dead battery affect half the 120 volt AC?

[Daveh]

Interested in hearing the answer. I know a lot of our appliances have 12 volt control boards and your AC thermostat is probably 12 volt. But I don't understand having no at all. 

[Kirk W]

I would need to check it out to do more than just guess. If your old battery has a shorted cell it may have caused an overload, but that is only a guess. 

[blrdck]

I understand that a shorted battery could affect the 12 volt DC but how could that affect the 120 volt AC not working which are on different circuits than the converter?

[Yarome]

1 hour ago, blrdck said:

...how could that affect the 120 volt AC not working which are on different circuits than the converter?

It doesn't.

The battery and "1/2 the 120 AC outlets not working" are not related. The 15 amp breakers are for your outlets. One trips.. you reset it.. they now work. The first time around are you sure that you completely disengaged the breaker... completely to the "off" position and then "on"... and reset it rather just flipping it back over to the "on" position? That would be my guess.

Second guess would be oxidation or corrosion on your breaker post, or internally, not making a proper contact, but in the process of moving it around while fiddling with it a contact was made. Don't know how old your rig is, how often it's used or what secondary factors may/may not be at play.

My money's on the former.

120vac outlets... problem solved.

A/C, and pretty much any of your other appliances (refer, WH, furnace, slides, water pump, etc.), are related to the battery. As Dave mentioned... they all utilize 12vdc control boards. 120vac power to your A/C unit may be just fine but the thermostat and controller require 12vdc to activate the unit. 

If a battery cell had shorted then you would be talking blown 12v fuses, which you didn't mention, so I have no idea how that entered the discussion. Completely separate and unrelated power systems.
 

[Kirk W]

10 hours ago, blrdck said:

I understand that a shorted battery could affect the 12 volt DC but how could that affect the 120 volt AC not working which are on different circuits than the converter?

It may cause a problem due to the converter drawing max load. As I said before, without being there to investigate and to take some meter readings, nobody can do anything more than to guess. After 40 years of electrical service work, I assure you that there have been times that a problem was resolved and even the professed experts could not give a supportable explanation for the solution, even with a very experienced tech making all sorts of tests and measurements. I suggest that you simply keep a close eye on things to be sure none of the issues return and don't worry about the exact reasons. It is possible that you did have more than one problem at the same time, but past experience tells me that it is not probable. Let's not make something more complicated than it needs to be. If you have no further issues, just accept that and travel on. 

[Daveh]

23 minutes ago, Kirk Wood said:

......... Let's not make something more complicated than it needs to be. If you have no further issues, just accept that and travel on. 

 

I would put this on the back of my trailer but it is a little too long 🙂. Still ,it would make a great tagline to a profile Kirk

[Yarome]

I prefer to stick with the obvious solutions first to avoid confusing someone with an off-the-wall extremely improbable issue and work down.

In the event of a shorted battery cell there is an inline 12vdc fuse. That "could" fail.. but then there is the converters output limitations, overvoltage protection (found in most modern converters which, not knowing the age or type of converter installed, yours may or may not have), internal fuses and a breaker feeding the converter.

So the battery/ies main inline breaker "might" not pop. The overvoltage protection "could" fail to kick in (is so equipped). The converters internal fuses "may" not pop. The circuit breaker in the power distribution panel "could" fail to trip... and if your outlets were tied into the same circuit as your converter then, yes. All 4 or 5 of those conditions being met then it is "possible" a shorted battery cell might kill your 120vdc outlets.

But I'm just guessing...

Who really knows how 12vdc or 120vdc really work anyway, right? 😁

[Kirk W]

6 hours ago, Yarome said:

But I'm just guessing...

Exactly! Just as I said before, nobody can do otherwise with the little that we know. 

12 hours ago, Kirk Wood said:

Let's not make something more complicated than it needs to be. If you have no further issues, just accept that and travel on. 

 

[Yarome]

1 hour ago, Kirk Wood said:

Exactly! 

I "guess" the sarcasm was lost in translation. 😉

YOU may not be sure, but the possibility of a shorted battery cell tripping the breaker on an isolated 120vac outlet string... in any standard battery/converter/PD panel configuration... as described by the OP...  is not a "guess"... it's physics.

Kind of like saying you were towing your 5er with your pickup, stepped on the brake and your 5er slides went out. 😄

Is there some miraculous/crazy/miswiring/catastrophic situation where that might actually occur? Nothing is outside the realm of possibility, but to discount any conventional wisdom or understanding of electrical systems becase there is a 1 in a billion chance that it "could" be "this", "that" or "the other".... no one can do anything but guess as to why... is ludicous.

Personally, if I hired a professional electrician and he was unable to diagnose a problem, but fixes it without even knowing how he did it, would not be anyone that would ever get my business again. Just because someone goes about doing something in the wrong way for a decade... or 2 or even 5...  doesn't somehow make it "right".

 

It seems I often see these, "No one really knows. We're all just guessing" statements when someone disputes information you've presented. Might be worth a little self examination why you feel that's necessary or how it contributes to the discussions at hand.

[Ronbo]

My mother in law keep loosing power to her laundry and bathroom. Called an electrician. He checked all the junction boxes, supposedly, and wanted to run new wires from panel to her laundry room. I to.d her to send him away as we’re going to be there in a week. She wired the house 50 years ago so was familiar with everything. I laced a ladder in the attic crawl way and when I climbed up, my hand fell onto some wires. The power came back. There were 2 junction boxes tight there he had not even touched. I opened them up, redid the connections and retapped the wore nuts. No more problems. Some electricians are idiots.

[Alie&Jim's Carrilite]

10 hours ago, Ronbo said:

 There were 2 junction boxes tight there he had not even touched. I opened them up, redid the connections and retapped the wore nuts. No more problems. Some electricians are idiots.

 

No, Some electricians think they find an easy dollar..... Drag some wire up the ladder, open an outlet or 2 in the laundry room, 3-4 hours later "Its Fixed"....

[Kirk W]

10 hours ago, Alie&Jim's Carrilite said:

Some electricians think they find an easy dollar.....

They are no different from any other service worker. Some are skilled and reliable while others are lazy and opportunistic. Some people have ethical standards while others will just look for an easy way out. It is true for every group, even RV folks.

[Ronbo]

12 hours ago, Alie&Jim's Carrilite said:

No, Some electricians think they find an easy dollar..... Drag some wire up the ladder, open an outlet or 2 in the laundry room, 3-4 hours later "Its Fixed"....

He truly had no idea where to look. He had been there for at least 4 days trying to fix the problem. This was his last resort. I am just glad my MIL called me befor she let him do his deed.