Power inverter

johnat4mc · 06-11-2018, 08:37 PM

I have a Xantrex pro XM1000 power inverter in a 38 ft Cedar Creed fifth wheel. The camper has started throwing breakers and I have traced to to the inverter. When I throw the inverter breaker in the camper, it throws the shore power breaker. There is no error code showing on the inverter, but when I turned it one (it had been off) it showed either battery or fault on the display but no error code. However, with it on something started smelling hot in the kitchen and something started popping. Obviously I turned it off.
So I assume I need to get the inverter repaired. And have I fried my refrigerator?

Thanks, John

SeaDog · 06-12-2018, 06:57 AM

Along with checking the inverter I would also check the battery condition and ensure thats not part of the problem. It might be that the inverter is not the problem you say the frig is fried could there be a short in the frig causing the inverter to draw high amps?

CHICKDOE · 06-12-2018, 09:39 AM

i'll bite, but i'm totally confused! a 1000 watt inverter should be dedicated to the refrigerator. it will draw power from the batteries, make 110 volt power, and send it to the refrigerator. there will be some type of transfer switch mechanism, either in the inverter itself or a small external one, that ensures the refrigerator is connected either to shore power, or inverter power, but not both.

in a standard install like this there is no connection between the inverter output power and shore power. there is no way the inverter can trip breakers in the shore power panel or trip the main shore power breakers. if you are tripping these breakers you have a problem with shore power, not the inverter.

the first thing to do would be to unplug the refrigerator and plug it into an extension cord running from a known power source. this will tell you if the refrigerator is working.

next thing would be to use a voltmeter or test device (lamp, radio) and plug them into the 110 outlet on the inverter. do they work when you turn on the inverter? that should tell you the status of the inverter. unplug shore power when doing this in case you have an inverter with the internal bypass feature.

all of the above is based upon a standard factory install. if modifications have been made all bets are off.

johnat4mc · 06-13-2018, 09:16 AM

Thanks for your replies. I plugged the refrigerator into another outlet and it does work, so I am thankful I did not fry my refrigerator. As best I know the inverter is wired as from the factory, although I did buy the camper used. I changed the inverter twice yesterday, both times they were salvaged units, same make and model. The first one at least would show an error message. Called the manufacturer tech support and went through the diagnostics that they recommended and seemed to indicate that the unit was bad. The second salvaged unit would not even turn on.

On the panel inside the camper there is a breaker marked INV, I assume that means inverter. Whenever I turn that breaker on, it throws the breaker outside. With that breaker off I can get everything to work but the refrigerator (which I now have plugged into another outlet and it does work) and the Zone 2 A/C.

I have called a mobile RV repairman but he cannot get here till Tuesday and he appears to be the only game in town.

Also another question. When all this started, when I turned the inverter on, there was a popping noise in the area of the refrigerator and it began to smell hot. Why was that? The inverter was not sending the proper power to the refrigerator I guess? Or could it all be a shore power issue? I am camped at a private campground related to a flying service, I am a crop duster. This all seemed to start when 4 other campers moved in, they are utility workers putting up a sub-station somewhere. It did not seem to start till they all moved in, but according to the owner, none of them are having trouble. Actually I guess that is three questions.

Again I appreciate your replies and any suggestions you would have for me.

Thanks, John

johnat4mc · 06-13-2018, 09:17 AM

Almost forgot. The batteries are less than a year old. Got them in January of this year.

John

CHICKDOE · 06-13-2018, 11:41 AM

ok i looked up the xantrex xm1000 inverter. it has an internal transfer switch. so that explains the circuit breaker labelled 'INV'. it would be used to control a/c power into the inverter / transfer switch.

you say when you turn this breaker on it trips to breaker outside. what it the amperage of your trailer and the outside power source you are plugged into? i'm wondering why the outside circuit breaker is tripping as opposed to the circuit breaker you mentioned that is labelled 'INV' or even the main circuit breaker in the trailer distribution panel.

you mention a popping noise and a smell behind the refrigerator. there might be a receptacle behind the refrigerator that the refrigerator is plugged into. this receptacle would be wired directly to the inverter. my guess is that the noise and smell you experienced are being caused by a loose connection in this receptacle. this is just a guess but it makes sense to me. it is also possible that the a/c wiring from the main distribution panel the goes into the inverter has a loose connection or short, especially after you having swapped inverters a few times. i'd spend my efforts of checking out the a/c cable going into the inverter and the output wiring going from the inverter to the refrigerator. you've got a short or loose cable somewhere in the path.

**Bama Rambler** · 06-13-2018, 02:50 PM

Sounds like a dead short, and from the popping you heard it could be in the fridge receptacle. I'd take it apart and see if it's shorted internally.

johnat4mc · 06-14-2018, 08:36 AM

Thanks for all your replies.I will keep looking.

John

CHICKDOE · 06-14-2018, 09:08 AM

there are a couple of other things you should check. unplug the refrigerator from the inverter. disconnnect from shore power and turn the inverter on, with nothing plugged into it. just check it to see if it turns on and shows the proper lights and indicators using only battery power. then plug something into it like a light or radio and see if they work using only the battery power. an output voltage measure would be nice at this point if you can take on. the intent of this is to determine if the inverter side of the inverter is working properly. now unplug everything from the inverter and turn that circuit breaker labelled 'INV' off. you might want to also disconnect a lead from the battery so that no 12 volt power can get into the inverter. now flip that 'INV' breaker. does it still trip the outside breaker? if so you know the problem is between you electrical panel and the a/c side of the inverter. if it does not trip that 'INV' breaker plug the same test devices into the inverter and / or take an output voltage measurement. there got to be a short somewhere.

johnat4mc · 06-27-2018, 08:40 AM

Thought I would post what the problem ended up being, at least according to the RV tech who came to the camper. Actually ended up being two problems. First, apparently there was a bad inverter. Second, there apparently is a bad wire somewhere in the line going from the inverter to the refrigerator. Anytime refrigerator was plugged into the outlet for the refrigerator, it would throw the circuit breaker on the panel outside. The problem there (someone had posted earlier wondering why the breaker was throwing outside) was that who ever wired the campground, put GFI circuit breakers on the outside panels. The RV tech said that should not have been done. Said would probably never had noticed a thing at a regular campsite. Anyway, thanks for all your help.

John.

CHICKDOE · 06-27-2018, 08:53 AM

i'm still wondering. you say there is a bad line going from the inverter to the refrigerator. wouldn't that be the refrigerator power cord? yet you say the refrigerator works if plugged into another outlet (indicating the cord is ok). it could be that you have two gfci receptacles in series, the one on the pedestal and the one in the inverter. this could be what is tripping the pedestal.

how do you know you have an inverter problem? does the inverter work from batteries if you disconnect from shore power (and the gfci on the pedestal)? can you plug into another pedestal without a gfci and see if everything runs ok on shore power (or power from a generator without a gfci)? i'd check these two scenarios before you assumed a bad inverter.

johnat4mc · 06-27-2018, 03:32 PM

The RV tech said (and he ws quite puzzled by it all) that he thinks in the line that went from the inverter to the refrigerator outlet, there was a loose or broken wire, and that the refrigerator had been getting it's power through the neutral, not the hot wire. Again, he said that in a normal campground where there were not GFI breakers on the main box, it would not have caused a problem. But in out campground, the GFI is detecting a problem in the return path so it trips. He said GFI breakers should not be put in campgrounds because by definition a camper is not all that well grounded, ie doesn't have a 5 foot rod driven in the ground as a house would. We have taken the refrigerator plug and plugged it into the plugin up near the stove, not the one behind the refrigerator. He tried completely bypassing the inverter by taking the AC input and output wires and putting a male plug on one and a female plug on the other. Whenever he would plug them in, the outside breaker would trip. He looked up underneath the camper to see if there were a junction box where he could troubleshoot the wire and there was not. He said would have to take the under panel off to trouble shoot and it is not worth that. We don't need to have the refrigerator on going down the road any way. Now..I understood very little of what he said. I don't understand electricity at all so most of what he said went over my head, but as best I understood it, that is what he decided.

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