FoxESS Community - Owners & Installers Forum

Hi,

Sorry to ask a possibly repeated question, I did a quick look and didn't see anything relating to this issue. My solar setup is as follows:

Fox ESS H3 Pro 15kW 3-Phase Hybrid Inverter
34 x 440W (3 strings 12+12+10) - Jinko Tiger Neo 440W N-Type All Black Mono Panels
Fox ESS EC2900 - 14.4kW Li-ion Battery (1 x Master + 4 Slaves @2.88kWh each)
3-Phase Export

The system was setup by the installer to run the house first, charge the batteries 2nd and then export anything else to the grid with the 100% priority for house consumption during the day. In essence my understanding on a good solar day , there would be ZERO draw from the grid other than the negligible Grid SYNC required of a few watts each hour or whatever the timeframe is.

As the sun drops and the solar produces less power, my understanding was that the batteries begin to pick up any short fall the house needs first and will discharge all night before charging as the sun comes up in the morning (providing sufficient power is in the batteries to not need grid import). The cycle then should just repeat. But.....

I'm seeing a nightly IMPORT from the grid the moment the sun drops to the moment the sun rises, not a full whack of usage but I was under the apparent naïve understanding that the batteries would cover 100% of the house usage at night so there is little to no Grid import.

But I'm pulling between 1.5kWh - 2Kwh per over night as seen on the octopus account usage. That doesn't seem right at all and the app even shows grid import. Is something not set correctly here, why would the batteries not cover the full load as they never drop below 88% for the following morning so there is no demand for the grid at all.

The screen shots are EXCLUDING the standing charge, this is over night usage showing before solar and then afterwards (Before solar starts at the bottom). Any help on this would be great please as if its a simple settings issue ion the inverter can I do this myself?

Thank in advance for any help.

Hi, welcome to the forum.

You have a large system there, and being 3 phase (and large) it is prone to using more power when biasing the grid in Self-Use, the amount of gird bias is specific to your system as it will depend on how you use the system, which bigger loads switch on and off and how frequently but 2kW isn't unreasonable.

The smaller 5kW single phase inverters would likely take between 0.5 & 1.5kW depending on the loads when running in Self Use.

The larger systems when updated with the latest firmware have a new feature called Grid Compensation, this allows the installer to set a bias power that will compensate for the normal incoming bias when running in Self Use and this allows you to use the batteries to compensate for the self use bias power.

Ask your installer to make sure to update you to the latest version of Master/Manager inverter firmware and also about setting a grid compensation value of approx 80 watts and hopefully you'll get the grid usage much, much lower.

Thank you Dave,

I will speak to the installer tomorrow and get this looked at. Many thanks

I'm waiting on the installer to come back to me but I took a photo of the inverter software versions. Are these up to date?

Ok, latest versions are -
Master 1.58
Slave 1.06
Comm(Manager/ARM) 1.33

Hi,

I'm still waiting for the installer to get back to me on these recommendations but where can I see the latest software / firmware version of the inverter etc from the mobile phone app or the FOX web login? IS that possible? Can't seem to see it as wanted to check the 3 versions of software you said were the latest?

Many thanks

In the V2 app click on Device and then Inverter, then click the serial number under the inverter picture and it will provide all that information

Thank you Dave,

I didn't see the small print where to click but have it now, thanks again.