Help troubleshoot Magnum 2000w inverter/charger -- very low AC voltage

[BTroll]

Can anyone help troubleshoot a Magnum 2000w inverter/charger that isn't putting out proper 110v power? Things like a 100w lightbulb, shop vac, and microwave will not work properly or turn on at all so I am trying to figure out why.

MS2012 is the part number, I tried calling their tech support twice today -- waited on hold for over an hour the first time before they said their phone system was down and it hung up on me, second time I left them a message and they said they'd call back -- and I never heard back.

The inverter worked previously but I just did a 12v rewire so I'd have to consider that the changes I made are related even though I was very careful and all of my 12v power works as expected. According to the Magnum display, the inverter is getting 13.2v from my lithium batteries, but the inverter is putting out a strange fluctuating AC voltage -- it was bouncing between 120v and 100v AC without any load, but now sometimes it will only put out about 20v AC (according to the Magnum display). When it is putting out 120v AC with no load, when I turn a 100w lightbulb on plugged into one of the outlets, the voltage its putting out drops to 68-70v and holds steady there (and the lightbulb is dim).

Does anyone know if the Magnum display is reading the voltage out directly from the inverter, indicating this is an issue with the inverter itself? I don't want to jump to that conclusion if there could be something else thats inhibiting its operation.

The lithium batteries should be fully charged from solar (Victron BMV shows 100% battery which is 400Ah) and I have about a 5' 2/0 + and - cable between the batteries and the inverter.

I also disconnected the "hot in" and "hot out" wires on the inverter to test and its still putting out that strange fluctuating erratic voltage. I also turned off all of the circuit breakers, still no change.

I plugged into shore power and the voltage holds steady, and also powers the 100w lightbulb much better and shows about 110v steady with the lightbulb on. The toaster also worked on shore power, and it doesn't through the battery/inverter.

Any ideas or anything to look at? Everything I find online references the fault light being on and a fault code but I have no fault light or code showing up on my Magnum display!

[twinboat]

Did you try it with a larger load ?

Is it a MSW inverter and are you using the correct volt meter ?

Check your search watts settings. It may be why the voltage is low with a small load.

[BTroll]

It won’t run a 1500w toaster, 1200w microwave, a shop vac, or power the lightbulb fully. When I turn the lightbulb on the magnum display drops from 120v to 70v.
Also the display says “Inverting”

[Reka]

just went the thru same, thing in my case it was the house solenoid acting up flipped the salesman switch a couple times and all good.

[Reka]

you could by pass the solenoid by putting the 2,4 or 6 guage wires together with a bolt, that will confirm if your solenoid is the problem

[BTroll]

Which solenoid are you speaking of?

[BTroll]

I have a manual battery cutoff switch but why would that be related? I have had it on and off a few times to test other things already.

[twinboat]

Most inverter/chargers are connected directly to the battery. They do use a large fuse.

May want to check that connection.

The house disconnect would have nothing to do with it. That controls small 12 volt items.

[twinboat]

Originally Posted by Reka

you could by pass the solenoid by putting the 2,4 or 6 guage wires together with a bolt, that will confirm if your solenoid is the problem

2, 4 or 6 gauge wires would melt on a 2000 watt inverter/charger.

[Reka]

have someone flip salesman switch you will hear it clicking, mine is located in the front run box under driver side window. monaco - you don,t say what type of rv you have

[Dutch Star Don]

This is a long shot. A neighbor had a similar issue, everything should the inverter working, but once a load was placed on it, it didn't work. He took it to two different shops and they finally replaced the inverter, but he still had the same issue.

As stated above, there is a large 250 amp fuse, about the size of standard band aid inline between the batteries and the inverter, on the positive cable. It's typically covered/encased in a rubber boot that snap opens. By accident I was checking the fuse and found that it had burned about 3/4 of the way through, but would still carry voltage. Once replaced, problem solved.

[YC1]

As Don is eluding to you need to be measuring the DC input voltage on the Inverter when under load.

It should be showing a low input voltage but sometimes things don't go to plan. Since you have messed with the input supply there is a good chance of a loose connection or as suggested a sick but not blown fuse. That would be rare but I never say never.

[BTroll]

Thank you, I will try to check into this today and report back -- I'm under the gun to move out of my house and into my RV this week and drive it cross country. I'm on a decent pace now but did not plan for the inverter issues so I'm concerned it will set me back.
Appreciate the help and hopefully can get this sorted out with your feedback! I'll update a bit later.

[BTroll]

Just to be sure -- assume the 100w lightbulb is a good load to put on the inverter since its obviously having issues with that?