FoxESS Community - Owners & Installers Forum

Hi All
Our battery went offline earlier today and the inverter screen is showing a Bat Volt Error.

I've powered the battery down / switch the battery breaker off for ~20 mins and switched it back on but it's still showing the error. Battery was discharging and charge was @ 37% when it went offline.

Firmware is fairly up to date (but I can update if it's related to this). Pic of error on inverter attached,

Does anyone have any experience / ideas how to get it back online?

Thanks
Tony

Battery: ECS 4300h (x3)
BMS: 2.008
Slave: 1.15

Inverter: H1-6.0-E-G2
Version_Master: 1.51
Version_Slave: 1.04
Version_ARM: 1.6

Datalogger
Version 4.14

Did you only power the battery off and on, or did you do the Inverter also?

Just power cycled both and it's back up and running now. Thanks! That was easy.

SandySolar wrote: ↑Wed Mar 11, 2026 8:34 pm Just power cycled both and it's back up and running now. Thanks! That was easy.

I was going to suggest it has to be done in correct order.
Happy you got it working for now, in case it occurs again, you may have to look a bit closer as to why.

SandySolar wrote: ↑Wed Mar 11, 2026 7:58 pm Our battery went offline earlier today and the inverter screen is showing a Bat Volt Error.

Any chance there was a firmware update about then?

I had 2 x 194 "Battery over voltage" errors the other day when I updated mine.

No - I wasn't running a firmware update. It just went during peak time battery discharge back to the grid. Fingers crossed it's a one off!

MaterialBarracuda48 wrote: ↑Wed Mar 11, 2026 8:39 pm

SandySolar wrote: ↑Wed Mar 11, 2026 8:34 pm Just power cycled both and it's back up and running now. Thanks! That was easy.

I was going to suggest it has to be done in correct order.
Happy you got it working for now, in case it occurs again, you may have to look a bit closer as to why.

Never stopped to think it there's a right order to things!!

I 'stopped' the inverter then powered down the battery, power cycled the inverter, started it up then switched battery on. Is that wrong order / is there a right order?

My installers left me a document with this on, but actually missed step 5.
I have rebooted a few times, and each time this works perfectly.

What can happen when you do it in the wrong order, is the battery is not seen by the Inverter from what I can tell. Hence I wake the battery 1st on start up sequence.


Shut-Down Sequence – (Switch OFF)
1. Turn OFF the PV supply at the consumer unit (3).
2. Turn OFF the AC isolator at the consumer unit (3).
3. Switch the AC Isolator at the inverter to OFF (2).
4. Switch the DC Isolators at the Inverter to OFF (2).
5. Battery off

Wait for your Inverter screen to go blank.

Then I do all of that in reverse.

SandySolar wrote: ↑Thu Mar 12, 2026 2:26 pm No - I wasn't running a firmware update. It just went during peak time battery discharge back to the grid. Fingers crossed it's a one off!

You don't have to as Fox are doing it to all installs it seems.

If you open your FoxCloud2.0 App, and press the bell icon near top right, it should show fault code if you look in your history.

You maybe lucky and it can tell you a fault code number: example error 194 = Battery overvoltage
You did mention you was exporting to grid when it dropped out.

MaterialBarracuda48 wrote: ↑Thu Mar 12, 2026 3:15 pm You maybe lucky and it can tell you a fault code number: example error 194 = Battery overvoltage

That error just happened to me again as I noticed a new battery bmu version v5.06 and scheduled an upgrade.

A one off fault is not too bad, a reboot typically cures.
If the fault keeps coming back, then it needs more investigation.

Any BMS over/under Volt errors will often indicate that the BMS has lost Cell Voltage limits, so needs calibration.
Dropped to 10% and held for a few hours, so it can settle and calculate, then up to 100% and held again so it can settle the cell Voltages. Then the BMS should know the 'end points' going forward.