H3-10.0-E Inverter shows Sw Bus Volt Fault upon shifting to EPS (EP5) when there is Grid shortage

[asad1999]

Hi all,

I own a H3-10.0-E Inverter hybrid 3 phase inverter. and a EP5 is attached for emergency load. Recently there was grid outage and my appliances which i have kept on EPS didnt turned on. I looked into the inverter and found this error on display screen but nothing was shown on fox cloud 2.0 (only errors of *No utility *Frequency fault etc.)

But when grid was available everything was normal no errors etc.

For those interested i have attached battery stats as well and the pictures of error as well. In the video you can also hear inverter trying to trip/changing to on-grid.

What could be the issue, previously there were grid outages and everything worked normally? The system is new and installed on 16th December 2024.

[Dave Foster]

This is the advice Fix give for that error -

Bus voltage out of range detected by software.
Please check whether the N line is connected to the GRID port of the inverter.
To upgrade to the latest software, at least ensure that the master is upgraded to
1.69 or above.
• Disconnect PV, grid and battery, then reconnect.
• Or seek help from us, if not go back to normal state.

I think the first sensible step will be to make sure that you are on the latest Master firmware - also worth checking that the appliances you have on EPS are highly inductive and overloading the output (disable all loads, switch to EPS, then enable loads individually).

Also make sure you have a Neutral>Earth bond in place when the grid is disconnected and the EPS is active (there should be ~0V between Neutral and Earth)