Inverter Issue

[Jerry Emert]

We are plugged in to known good 50amp power source.  Discovered this morning that the HydroHot furnas function not working this morning so we had a space heater warming the inside.  The microwave was turned on and we lost 115ac. 
1.Checked all the usual GFCI plugs and the inverter breaker box in the Stbd side bay and found the galley breaker popped.  Turned it back on and problem continued with no 115 in the coach. 
2.12vdc items in coach still working. 
3.Checked inverter remote and found fault light which cleared when I cycled the inverter button.  I failed to note what the fault said exactly.  Over voltage or something similar was part of it.
4.Noticed that the charger indicator was not lit and would not come on when I cycled the button. 
5.I checked the inverter and found the green led was blinking green.  I tried to reset it but still green blinking. 
6.The the invert function is working.  When I turn on the inverter I get some 115 in the coach but batteries are not charging. 
7.Battery voltage down to 12.2. 
8.I tried the hard reset by unplugging the coach and taking the battery cables off the inverter.
9.After waiting 10 minutes I reattached the battery cables to the inverter and plugged the coach in. 
10. No change in 115 status.
11.Both AC units and the washing machine are working fine.
12.The inverter is a Magnum MS 2812 installed in June of 2014. 

Right now I believe the pass through circuit (or inverter internal transfer switch) is not functioning.  Please tell me I missed something because I have extension cords running all over the place for reefer and space heaters and computer charger of course. 

Any other ideas? Please tell me I missed something stupid!

Whats the current favorite inverter out there?

Thanks.

[Steve Huber Co-Admin]

Jerry,
Maybe I missed something in your writeup but if I understand correctly you have no 115 AC when plugged in to shore power. If so, your inverter is not the issue. Verify you have not lost a leg of the shore power at the pedestal. You should see 120V between ground (lowest connector and one of the side connectors. Then also 120V between the top connector and the other side connector. If OK. then check at the transfer switch.
Steve

[Jerry Emert]

Jerry,
Maybe I missed something in your writeup but if I understand correctly you have no 115 AC when plugged in to shore power. If so, your inverter is not the issue. Verify you have not lost a leg of the shore power at the pedestal. You should see 120V between ground (lowest connector and one of the side connectors. Then also 120V between the top connector and the other side connector. If OK. then check at the transfer switch.
Steve

Thanks Steve, both heat pump units are working fine.  I know they get AC before the Inverter does so I know power is good coming in and the transfer switch is good.  Just no pass through or battery charger.

[Scott Shearer]

Jerry,

Remove the AC access cover on the side of the Magnum and check the input AC and output AC (pass-through).

If there is input voltage and no output voltage, then the invertor is the problem.
If there is no input voltage, then the problem is upstream of the invertor (main breaker panel or the wiring to the invertor).
If there is both input and output voltage, then the problem is downstream of the invertor (invertor sub-panel or wiring to it).

Otherwise, it looks like you covered all the bases.

FWIW, this winter we had nearly the exact issue with our PT. I was running a space heater (and I knew better), lost all pass-through AC and charger functions. I didn’t want to tax the batteries, but the invertor function seemed to work.

The initial err-code was over-voltage then became an internal fault err.

I went through the troubleshooting steps with several resets; the inverter would work for a few minutes then err-out.

It took several attempts, but I finally got through to Magnum tech support. The tech was very thorough and patient, not at all in a hurry.

We repeated all the steps that I had already performed including a hard reset.

His diagnosis was a faulty control board but he was concerned that something else was going on…didn’t want to start throwing parts at it. He suggested a bench test. I took the invertor to an authorize repair facility where they diagnosed it as a bad control board and a bad AC board.

It was about $770 for the repair. I had to find the control board myself as they were extremely scarce, none were available from Magnum.

I can’t help but feel that the damage may have been self-inflicted by running the space heater through the invertor (pass-through, not inverted).

Control board $330
AC board and labor $440

-Scott

[Jerry Emert]

Thanks Scott. I didn’t think to check the voltage inside the inverter. Great idea. It sparked another thought though. We are on our property, on a mountain, in NE TN. It’s in the 20s and 30s all night.  I’m thinking of wiring 30 amps from the pedestal into the 115 output of the inverter to power the house, possibly at the inverter breaker box. There are no RV repair or sales in this area so it’s just another adventure. Thanks again.

Any nays or yays on my rewire idea?  Thoughts anyone?

[Fred Brooks]

    Jerry,
  Do as suggested by Scott. Confirm the incoming voltage to the inverter/converter. If you have 120 volts coming in and NO 120 volts output, the issue is the control board and or the "pass-thru relay" If that is the case, and you have to get by temporarily until you can have it repaired or replaced, you can remove the "incoming romex" and the "output romex" and wire nut them together. Black to black, white to white, and ground to ground. By doing it this way, you have by-passed the inverter/converter and have 120 volts going to all the respective inverter circuits down stream. The drawback now is that you have NO means to charge your house batteries. You can get by with a stand alone battery charger like a Schumaker from Walmart (25/50 amp). Please DONOT rewire another 120 volt source from the pedistal. Bad idea! Fred
 

[Jerry Emert]

Great idea for bypassing the inverter!  Thanks, exactly what I was looking for.

[Jerry Emert]

    Jerry,
  Do as suggested by Scott. Confirm the incoming voltage to the inverter/converter. If you have 120 volts coming in and NO 120 volts output, the issue is the control board and or the "pass-thru relay" If that is the case, and you have to get by temporarily until you can have it repaired or replaced, you can remove the "incoming romex" and the "output romex" and wire nut them together. Black to black, white to white, and ground to ground. By doing it this way, you have by-passed the inverter/converter and have 120 volts going to all the respective inverter circuits down stream. The drawback now is that you have NO means to charge your house batteries. You can get by with a stand alone battery charger like a Schumaker from Walmart (25/50 amp). Please DONOT rewire another 120 volt source from the pedistal. Bad

Scott and Fred, I found where the 120 input to the inverter comes from. A small junction near the inverter. I disconnected all the wires in the box. One comes in from an unknown source and the other I can follow directly to the inverter and is labeled 120 AC in. I checked the voltage and it is just spurious on both cables. So there is no 120 getting to the inverter. I assumed that the 120 in that box is coming from the breaker box in the rear closet. The breaker for the inverter is there. The breaker is working and the output of the breaker is 120vac.  So now I’m confused!  It looks like a bad wire between the breaker box and the inverter. What a coincidence if true. I can’t see how a space heater and microwave could burn through 10 gage wire. My next step is going to try to check that wire out with an ohm meter. The way we would do it in the Navy would be to attach one end to ground and then check the other end to ground to see if the wire is good. Going to go figure that out now. Any other ideas I would appreciate it. Thanks.

[Fred Brooks]

    Jerry,
Good news that the issue is upstream of the inverter. Monaco is famous for J-boxes along the route for the sake of production. Glad you narrowed it down. It sounds like to me you are looking for a melted wire nut. Trace the romex backwards from the J-box that is supplying the 120 volts to the inverter input. The fact you were putting a 1500 watt load on the incoming supply suggests a loose wire nut. With the coach power disconnected, perform a continuity test between the circuit breaker output at the house panel and last j-box and work your way physically towards the house breaker box. Soldier on my friend, you will find it!

[Jerry Emert]

This keeps going in odd directions. I originally checked the output from the breaker in the closet. I had 120. As I said before I checked in the J box in the bay and nothing. I put a jumper between the disconnected neutral in the breaker and one in the J box. Good continuity. Checked the black just for giggles knowing that it was bad at this point and it was good blowing my mind. So I swapped a couple of breakers and now I had power in the J box. So the breaker was bad in the closet box. Got a new breaker and now that’s fixed but the inverter still has the same problem. No charging and no pass through.  So tomorrows project will be to hook up a piece of 10/3 Romeo between the inverter 120 input and the inverter 120 output to get all my plugs and such back.
Another funny discovery or maybe I am just wrong but I always thought that there were some receptacles that were not off the inverter. I don’t have anything. Which means that every receptacle in this coach is running off a 10 amp breaker on the inverter sub-panel?  Does that sound right?  If not where is the breaker for the rest of them?  The washing machine still has power so wife is happy!  Thanks for thoughts!

[Fred Brooks]

   Jerry,
The output from the Inverter should go to a sub-panel with circuit breakers. My coach has the sub-panel mounted on the compartment ceiling near the inverter. Not sure of the location on your coach. Fred

[Fred Brooks]

   Jerry,
Here is the schematic for a 02 & 03 Patriot. You can see the 3 different circuits being powered from the sub-panel from the inverter. Fred

[Jerry Emert]

Thanks all. Inverter is bypassed. I have a charger on the batteries and a friend who has a board and is an authorized magnum tech. Good to go for now. Appreciate everyone’s help.

Jerry.

[Eric Maclean]

Jerry
Be very careful back feeding the inverter circuits the manuals for these inverters say that back feeding the inverter as you are suggesting will damage the inverter circuitry.

If you want to feed the inverter powered circuits directly it is best disconnect them from the inverter to avoid back feeding into the inverter and damaging the inverter.

Hope this helps
Eric

[Jerry Emert]

Jerry
Be very careful back feeding the inverter circuits the manuals for these inverters say that back feeding the inverter as you are suggesting will damage the inverter circuitry.

If you want to feed the inverter powered circuits directly it is best disconnect them from the inverter to avoid back feeding into the inverter and damaging the inverter.

Hope this helps
Eric

Thanks, I would never back feed into the inverter itself. I removed the output from the inverter and fed the input into the output Romex. It’s bypassed completely. No 120 is touching the inverter right now.