FoxESS Community - Owners & Installers Forum

Hello,

I have a FoxESS inverter with a home battery and solar panels, installed about one month ago. Everything worked as expected until around the 14th of June, when the behavior changed.

Inverter: H1
Version_Master: 1.35
Version_Slave: 1.03
Version_ARM: 1.43

Yesterday evening around 8pm the battery dropped very fast, from about 85% to 20% in less than an hour, with nothing special running in the house. Then in the middle of the night it started to charge from the grid on its own, which it never did before.



When I look at the grid power meter, I now see flat rectangular plateaus at a fixed power, around +4500W (charging from the grid) and -4500W (discharging to the grid), lasting several minutes. This is very different from normal solar production or normal consumption, which are always noisy and irregular. A flat plateau at a fixed power looks like a forced charge or forced discharge order from the inverter.

On the attached screenshot (17 June, 00:00 to 16:00) you can clearly see these flat plateaus at about -4550W during the night and the morning, including periods when there is no solar production at all.



For comparison, a few days earlier (7-8 June) the grid meter was flat at zero during the night, with only noisy solar production during the day. No grid charging at night, no fixed plateaus.



My settings are the usual ones: minimum SoC 10%, maximum SoC 100%. I am in Self-Use mode, like since the beginning, and I checked: there is no schedule active. I did not change anything myself.



My installer told me that other clients seem to have the same issue, so it could be a firmware update that changed or activated something. One colleague also suggested it could look like a battery calibration run.

Is this a known behavior after a recent firmware update? Could something have been activated by itself even in Self-Use mode with no schedule? And if it is a calibration run, how often does it happen, because doing this when there is no solar production is a problem.

Thanks for any help.

That looks like a battery dump/cycle which you tend to see when there are CT clamp issues - if nothing has changed on the system i.e. there has been no work on it, CT clamp removed/replaced for any reason I would strongly suspect that this is a reverse meter sensing problem, i.e. the inverter believes that the CT orientation has changed and has flipped the polarity.

There is an installer setting that can be adjusted to stop this happening - ask your installer to disable the automatic meter reverse connection detection (which can be done remotely)

Thank you for the answer!

Quick update on my side. I called my installer about this. The CT / reverse meter detection lead makes sense to him, but he now has a bigger problem: he has completely lost access to my installation in the cloud view, as if my system had been deleted. So for now he cannot check or change any installer setting remotely. He has contacted FoxESS support and is waiting for them to understand what happened before he can do anything. I will update once I know more...

Also a question while I wait: night is coming in my area, so no more solar production. With this problem going on, will the battery try to charge from the grid during the night? How can I avoid that? Should I change the max threshold (max SoC)?

ok, fingers crossed.

I think it's very likely it will do the same and start to charge from grid - if it does, you could try a full shut down and restart, it might auto detect correctly on startup and it should stay like that until the morning.

Another option is to stop the inverter, you can do that at the inverter itself by holding the 'tick' button (3rd button from the left) and the inverter will say 'Stop' press again and it will stop all inverter operation.
(but don't forget to start it again when the sun comes up by repeating the same process, but when it says 'Start' click again)

Thank you!
I could not find how to do the full shutdown and restart as you described, so I just stopped the inverter.