FoxESS Community - Owners & Installers Forum

Good morning,

I have a KH10 fox inverter coupled with the ECS2800 fox batteries (x2 with total 5kWh), installation was relatively simple and have put a CAN logger between the battery and inverter to record messages and signals due to an EPS overload error I have been getting.
To my undertsanding the inverter (in EPS mode) can output 10kW of power. However due to the battery configuration I have, I would only be able to output close to 5kW (limitation on battery discharge limits). As a test I have only plugged in an oil heater and LED camping light to the EPS output of the inverter (both cumulatively only draw about 1500W together at max power, obviously well below the 5kW limit) and the inverter seems to handle this fine for about a minute or two before throwing up the EPS overload error and going out of normal operation mode. It then goes through the checking cycle and eventually returns to normal mode only to produce the EPS same error a few moments later.
I have tried looking through this forum as well as the internet and haven't been able to find any information about this error. Has any experienced this or has a solution/explanation as to why this would be happening?
I haven't been able to spot any issues in the CAN comms when this error occurs and I assume it might have to do with the config of the inverter.
Within the remote settings for the inverter I have set the EPS output to UPS mode, power limit to 100%, auto recovery is on, the frequency is set to 50Hz and the rated volatge is 230V.
Any help would be greatly appreciated.

Regards,
Murray

1x KH10 Fox Inverter
2x ECS2800 Fox Batteries

It should certainly be capable of supporting that load without any trouble, the BMS might throttle the battery current depending on state of charge but you'd still expect a minimum of 2.5kw at 20C, obviously in a good state of charge it would be higher than that.

The settings you have would appear to be correct - it might be worth checking in Settings, Battery that you have the inverter maximum charge current set to 50A (or as high as it will let you set it).

Are you sure it's an EPS overload and not a grounding fault ?

As the KH is relatively new, there have been lots of firmware releases for it - Fox don't provide release notes so with all problems it's best to start by making sure your firmware is totally up to date.

Latest versions on the fox cloud for KH are -
Master: 1.34
Manager: 1.27
Slave: 1.01

Hi Dave, thanks for replying so quickly.

I have set the output current to the maximum of 50A and the BMS is not throttling the current (I have been able to see on CAN traces that the discharge current transmitted fomr the BMS remains at 50A). I have been going through the thread on this forum (found at viewtopic.php?t=52) and am thinking it may be a grounding error but am not 100% sure. The inverter and battery have PE connections between one another (connected using standard yellow and green PE cable on the PE screw terminals on the side of the inverter and battery), within settings the grounding has been disabled since everytime I disconnected grid to test the EPS mode it would trip the mains breaker while grounding was enabled. The installation site does have earth protection through an earth rod (I think, am about 90% sure but will have to double check). The mains trip is concerning me though.

My fimrware versions for the inverter are -
Master: 1.14
Manager: 1.09
Slave: 1.01
Could I ask where I could see what the differences are between the firmware versions?

Any thoughts? Thanks

Regards,
Murray

Those are really old versions, before you do anything else I would get them updated.

I don't know for sure what all of the differences are but a lot of bug fixes, the KH is able to bond the N-E on EPS and I think you get an option to disable that (which might help), plus extra features like force charge/discharge and the MaxSoC now works correctly.

If you have agent access you can update them yourself, do Master first, then once it has completed and restarted do the Manager - if you don't have agent access email Fox service with your inverter serial number and they'll do it for you remotely.