MultiPlus 2 Inverter and charger not working

DIY
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1

My Inverter/Charger is no longer working. I installed the MP2 in 2022 and it has worked flawlessly until now.

Both the inverter and charger do not work. I have a Cerbo GX and what I see is that when I turn the switch to ON the State briefly shows the word FAULT and then the State changes to “Unknown” and then the Switch changes to “Charger Only”. The DC Voltage reads normally (13.05V) and when I go to “Alarm Status” it shows a zero (0). - below that all the different options show “Ok” (ie. Low battery voltage, Temp, Overload, DC Ripple, Voltage Sensor, Temp Sensor and Phase Rotation). When I select “VE.Bus Error 8 / 11 Report” the screen is blank.

When I try to operate in Charger mode (with generator running) the system switches to “Passthru” instead of charging . The AC-In L1 nd AC-Out L1 show normal values indicating the system is “seeing” good AC coming from the generator.

I have tried turning the system on and off several times, both by shutting off the master DC power switch which feeds the MultiPlus, and I’ve tried flipping the rocker switch on the front cover to Off then On again.

When I run Victron Connect, I do see the Multiplus on the My Devices list, and I can select the MultiPlus from the list and it opens the display showing the status of the device.

Another odd thing is that if I try to set the Switch to On a second time, I do not see State=FAULT, it just reads “Off”.

Also, the first time I tried this was 2 days ago, then the next time I tried this today, the inverter actually worked after flashing the word “FAULT” in the State field. When this happened I opened Victron Connect and selected the Multiplus and immediately the Inverter stopped working, and has not worked again since even though I have repeated the exact steps several times.

Ive also tried to restart the VE.Bus system via the Cerbo (Advanced → Restart VE.Bus system) which had no apparent affect.

Is this system toast? Is there anything else I can try?

Thank you.

2

Update: I ran the VEConfig app and removed all the assistants. I had 5 assistants installed. After removing them and updating the device (“Send Settings”) everything is now working again, but I am baffled as to why. Both the inverter and charger are now working.

The assistants I had were:

  • relay turns on external fan when internal fan is active
  • relay turns off external fan when internal fan is inactive
  • relay turns off AC Line In when SOC% is below threshold (set via BMV-700)
  • relay turns on AC Line In when SOC% is above threshold (ditto)
  • relay turns off charger when BMS signals (ie. overtemp, undertemp, HVC/LVC, etc)

I can live without these assistants. I am now running the generator and charger for about 5 minutes without issue. I am suspicious about why this is working now and I have low confidence that it will continue to work because I do not know WHY deleting the assistants resolved the issue.

If the system continues to work for an hour or two, I will shut down the charger and generator and try to add the assistants back one at a time (or 2 at a time since the relay assistants are in pairs, one for when the relay is on and one for when it goes off as described above).

Does anyone have any ideas why this is working now and why deleting the assistants resolved (apparently) the issue?

THANKS!