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sam-carleton asked

Inverter Alarm when unplugging from shore power

I'm in the USA so on 110V. I have had my VE system in my travel trailer two weeks now and am running into a strange problem. My setup: The travel trailer is a 50A trailer so I have two Multiplus 3000 in it, one for each leg. I am pretty sure they run in parallel, not split phase since it is my understanding RV's don't ever need true 220.

It is on shore power right now and is limited to 13A, and everything works as expected. I can run both air conditioners and the Multiplus's kick in to to provide the energy needed. The moment I unplug the shore power the inverters stop inverting and the whole RV loses ac power and I see the "Inverter Alarm #1 device switched off".

How do I troubleshoot this? All the fuses are good, the batteries have 13.5v. There is a Hughes Voltage Booster with Surge Protection installed, it is deep enough that it takes some tooll to see the status lights.

P.S. I have called the installer, but they are OOO so I am posting here, too.

multiplus in parallel
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dc-marine avatar image dc-marine commented ·
Your Multis are most likely running in split-phase otherwise they need their own neutrals since the loads wouldn't be balanced as one phase and would burn up a single neutral. Food for thoughts.


One thing I could think off would be that one of the multi has the black switch set to charger only ?


Or a bad ve.bus configuration from the installer.

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4 Answers
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sam-carleton answered ·

We found the problem! I talked with the installer today and we went through the whole system and found the problem. I am guessing multiple parties made mistakes that caused it...

BOTH inverters were physically set to charge only!

Here is what I *think* happened... When I first got home two weeks ago I tried going into the Cerbo GX and setting it to charge only and it didn't work. I found that a bit strange, but I figured it was because I was on 110V, not 220v.

Then last week I installed the SmartShunt in metering mode to meter the DC is going to the camper. The SmartShunt is right next to one of the Multiplus'.

My theory: When I picked the unit up the inverter farthest away from the new SmartShunt was in charge-only mode, thus why I could not get that mode to work when I first got home. Last week when I was installing the SmartShunt I inadvertently flipped the other inverter to charge only, too.

Now that both are in the right position everything is working as expected. I am currently on invert only and I can also be in charge only, both work fine!

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kevgermany answered ·

The alarm is normal, can be switched off.Odd that the inverters stop, they should continue on battery.

Do you have a GX device, like a Cerbo in the system? To troubleshoot we need info from that .Also to turn the alarm off.

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sam-carleton answered ·

Yes, I do have a Cerbo GX. I was running the large image, reverting back to the normal image and that had no change. While I don't have the MK3, I just ordered one and it will be here on Saturday. What can I do in the meantime via the Cerbo GX to troubleshoot this?

What is super weird is that everything works when on shore power, but nothing works when disconnected. The travel trailer was parked in my driveway and I played around with it a bit a week back and all was good. The ONLY thing that has changed is that I added a SmartShunt between the Lynx Distributor and the travel trailer's DC system.

I don't see how that could be a factor, but who knows :)

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kevgermany answered ·

In the Cerbo, settings, system settings, monitor for shore disconnect. Disable that. Should stop the alarm.

Also in the Cerbo menu, under the multiplus, the switch should be set to on.

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