Off grid restarts every 5 minutes...

[Ultek]

Hey
We had quite a storm and the power grid went down. The inverter switched to offgrid mode unfortunately it restarts the power every exactly 5 minutes (the message "grid volt fault" pops up for a while and then goes back in "off grid")
What could be the cause of this?

I have hybrid inverter FoxESS H3-8.0-E

Thanks for help!

Edit: when production from pv at the morning went a bit above 0% the resseting issue stopped...

[Dave Foster]

Do you have batteries ? - if it stopped doing it when the PV got above a certain level it sounds like your batteries maybe off-line - a complete shutdown and restart should clear that - to do that turn off PV, turn off AC, power off batteries, open battery breaker.... wait for inverter screen to go blank, then close battery breaker, power on batteries, turn on AC, turn on PV.

[Ultek]

Yes, I have batteries - 4x Mira-HV25
In general, in the evening everything worked fine - the electricity for the house was from the batteries (TV, refrigerator, etc. totaling 300-500W of use).

The only problem was with that reset every 5 minutes, which ended as soon as the voltage from the PV came on at the morning

I will try to reboot everything and see if it helped.

[Ultek]

Unfortunately, it didn't help. I restarted everything including the batteries (the screen on the inverter went blank) and just again after sunset the inverter started to restart every 5 minutes.

Does it matter that only 1 phase is available from the mains?

[Dave Foster]

Unfortunately, it didn't help. I restarted everything including the batteries (the screen on the inverter went blank) and just again after sunset the inverter started to restart every 5 minutes.

Does it matter that only 1 phase is available from the mains?

Yes I would have thought so, if 2 phases aren't connected you would expect it to report grid lost faults - but in all honesty i've never seen a 3 phase inverter with only 1 phase connected - that sounds like trouble.