How Should a FOX ESS System Work in Self-Use Mode?
Hi,
I have a FOX ESS system with an EP12 battery and a 5 kW hybrid inverter installed on 18th December. It was sold with the idea of overnight off-peak charging from Ovo, but I was later informed this option is no longer available.
The system is set to Self Use mode with a minimum SOC of 10%, 10% battery reserve, and grid charging turned off. However, I’ve noticed the system exporting to the grid while the battery is only around 38%, and importing power even when solar generation is active. Overnight, the battery also charged above the reserve level, which I didn’t expect.
Can anyone briefly explain how Self-Use mode is supposed to behave, and whether it’s possible to access or adjust more advanced settings beyond the basic controls?
Thanks.
Re: How Should a FOX ESS System Work in Self-Use Mode?
Normally Self-Use mode is as follows: The Solar (PV) will first supply the house Load, then any excess will fill the battery up, then once the battery is full, it will then export the remaining PV.

Example, 5kW of PV, and a house load of 1kW, the battery would charge at 4kW until full, and once full, the 4kW becomes export to the grid.


If OvO tariff is pants, or is causing your grief, it might be an idea to look at Octopus.
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Re: How Should a FOX ESS System Work in Self-Use Mode?
Ever since I updated the app to the newer version I have experienced the same thing. the older version charges the battery first then start sending the rest to the grid but it seems to send the electricity to the grid first instead. Also when I force to discharge the battery to sell to the grid, it does it but even when it has enough charge left in the battery, it uses electricity from the grid instead of discharging from the battery. The new update has been really annoying.
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