FoxESS Community - Owners & Installers Forum

Our system (FE-H1-6.0-G2 inverter & a single EP5 5kWh battery) was installed in March and has been running as expected until today. As we were shutting down for the evening, I noticed we were drawing from the grid so I checked the app and discovered the fault message. The fault apparently occurred at around 8:00pm. There were no other errors, just the over voltage alert. The system is now in failure mode and no power is being supplied to the house.

Previous answers for this say to turn everything off and back on. I don't know how to do that. Where do I find instructions for this?

Is it safe to leave the system in failure mode until the morning? I don't want to be fumbling around in the dark on high voltage equipment.

And why would I get an over voltage failure late in the evening when the PV is almost down to zero?

I'm happy to learn but don't know where to start.

There is a video here which tries to cover the majority of the isolators, switches, etc.. you will see. viewtopic.php?t=5

The basic process is as follows-


Turn off PV solar to the inverter (DC isolator)
Turn off AC to the inverter (AC isolator or breaker)
Power off the batteries using the ‘power’ button on them.
Open the battery DC isolator switch.

Wait for the inverter screen to go blank.

Reverse the process, i.e.

Close the battery DC isolator switch
Press (and hold) the Battery Power button until the lights come on.
Close the AC isolator switch
Close the PV (DC) isolator switch

Thanks Dave

The error seems to have cleared overnight. If I'm reading the up/down arrow on the alert history I got two alerts (8pm and midnight, with up arrows) and an "error resolved" alert (5am, with a down arrow). Since then, we've been getting enough from the panels to supply the house so the battery remains at 100%. I'll continue monitoring the behaviour to make sure all is well.

Should I cycle the system anyway? I've found all the relevant switches apart from the battery isolator. I'll look again now that I have daylight.

Is it normal for an over voltage error to resolve itself like this?

Yes it is normal for the alarm to go away again as at 100% soc the batteries will not accept charge until they fall back a few % and in that time the voltages would have settled.

I genuinely work on the principle that if a fault can go away on it’s own, it can come back on it’s own.

I don’t think you need to cycle the system but instead make sure the battery is cycled i.e. take it down to 10%, then back up to 100% - when you do that the BMS will re-learn the limits and should avoid a cell (or cells) being over voltage.

The other thing to do is to make sure your battery firmware is up to date, I am seeing the latest as 1.007 - you can check that in the app by clicking ‘Device’, ‘Battery’ and then click the serial number below the picture of your battery, it will show the BMS firmware version there. If it needs updating you could either ask your installer or in the app, click on ‘Me’, ‘Contact Us’, ‘Support’ in the description ask for your battery firmware to be updated.