FoxESS Community - Owners & Installers Forum

Hi guys,

Just had my Fox ESS Evo 10 installed yesterday, I have set it to not charge or discharge at all until I get my EV Tarrif (Have no solar, just a battery system to take advantage of cheap night rates..)

I noticed it drained from 61% to 55% over night (7 hours ) and indeed it shows on the fox app and and the inbuilt display a discharge of around 80 watts continuously.

Is this a normal amount of parasitic usage for the battery to drain when it's doing nothing?, or should I be looking at configuration / setup or firmware update to help lower?

I have the 5kw inverter for reference.

Thanks

Sounds like the inverter is still running even with limited load so you’re seeing the worst case system losses or battery warming maybe?

Once the system is commissioned check back in should you need any help.

Will wrote: ↑Sat Dec 20, 2025 6:35 pm Sounds like the inverter is still running even with limited load so you’re seeing the worst case system losses or battery warming maybe?

Once the system is commissioned check back in should you need any help.

Thanks very much - it has bene setup and is in use, if that is what you mean by commissioned?

Would love to understand what is using that 80 wats an hour, and if i can do anything to decrease it.

Many thanks.

I'm seeing the same, 80W of drain and cannot pin point it to anything, running EVO 10 -5 - H, new install.

I had over 100W of parasitic drain when my Evo 10-8-H was first commissioned. After the last firmware update, it’s gone down to about 70W. Installer said I should expect some parasitic drain but wasn’t sure how much, as these units are quite new.

That feels about right for a 10kW inverter, the drain is effectively the system losses, and when idle it is power taken to keep the inverter awake, logging, and grid tied with the various conversion losses to get from DC to AC (it has a number of large capacitors that are necessary for the regulation and smoothing of the grid connection).

I'm not sure whether the EVO has yet been provided with the meter compensation setting, many of the other G2 inverters have had it added recently (i.e. H1, KH, H3 Smart).

The meter compensation setting effectively allows the installer to change the level of bias i.e. the amount of power taken from the grid when idle, instead it is taken from the battery and whilst it is impossible to make the system losses disappear it certainly helps to avoid taking power from the grid at peak tariff and allows you to get closer to (near) zero grid usage.

For the EVO owners it would be worth asking your installer to see if it is available yet, if it is you can set it to your desired level of compensation, many people go with -50 watts - if not be a good thing to raise with Fox support to see if/when they might add that feature.

All of that makes perfect sense. I’ve emailed Fox support asking if meter compensation is available for the EVO on the present firmware.