FoxESS Community - Owners & Installers Forum

oh dear, oh dear.....
An unexpected power cut tested out the new installation today...and I am not happy
The whole point of using this expensive system was to prevent interruption of the supply to the house

The website https://fox-ess.uk/eps-box-sp-backup-gateway/#eps-more makes a point of, and clearly states that it provides uninterrupted power, changes over instantly, seamlessly and without interruption

I quote:
Whole home backup for residential storage installations

The Fox ESS EPS-BOX-SP is a single-phase whole home backup gateway that provides uninterrupted power during grid outages. Designed for single-phase installations, it automatically switches between on-grid and off-grid modes to keep your essential (or all) household circuits running without interruption.
How it works

The EPS-BOX-SP sits between your Fox ESS inverter, utility supply, and household circuits.

Normal Operation – When the grid is active, power flows normally from your solar and grid supply.

Power Outage – The EPS-BOX-SP instantly disconnects from the grid and switches to your battery and solar supply, maintaining power to your home.

Grid Restoration – When the grid returns, it seamlessly reconnects and resumes standard operation.

...except that it doesnt....when the power cut happened the whole house went off, then a few seconds later (!!!!) the supply to the house resumed from the battery......when the power came back again the same thing happened

I later ran the test again this time using the supply isolator switch to give a clean break and exactly the same happened.....router died, NAS offline, CCTV offline, PC shutdown potentially with open files then went offline etc. etc

Even this says the switchover time is only 20mS

https://www.google.com/search?q=fox+kh7 ... fId=ChxjMe

This is exactly the scenario I was hoping to avoid!

Completely unrelated but it is now pitch dark but the panels are showing 240V albeit at zero current...

You are obviously upset, but what Inverter do you have, and what errors are showing on the screen?
If you have a small 3.68kW Inverter and 5kW load, it won't handle it.
If your battery SoC is not enough, it won't work either.
Then theres the chance they wired things up wrong.

If you can provide more details, then some help can be given hopefully.

Hi, indeed I am not happy.....
system comprises:
14 x Aiko Neostar 2p plus 475W panels (6.6 kWP)
Fox EP12 10.4kW usable battery (>40% SOC)
FOX KH7 7kw hybrid inverter
EN-EPS-BOX-SP gateway
Pretty much all perfectly matched as far as I can tell...

Same inverter as mine, should be able to handle 7kW EPS load... unless you was using more than that at the time.
Do you have fault codes on Inverter screen?

I would expect grid loss and Voltage warnings to be stored (and usually in the FoxCloud2.0 App you can view once running) on the Inverter screen/history.

No errors or messages
Load was maybe 3 or 400 watts no more

Sounds like you need to chase the installers down to check into this.
I added UPS to all the important items, don't want my NAS to turn off either

I have had three UPS running for years.....one on the PC & bband /wifi, one on the TV and AV system, one kn the CCTV etc.....as well as going solar I opted for the Fox gateway in order to get rid of the UPS and their expensive battery replacements
The specs clearly state NO break and elsewhere 20mS which is fine....not the several seconds I am getting