FoxESS Community - Owners & Installers Forum

I'm trying to understand is how did my battery, last night at 19:10 02/12/2025, go from 100%SOC to 84% when according to these logs, hardly anything being exported or imported - see top attachement

Comparing the log file with what actually got exported to Amber (see bottom image), clearly some data never made it to the log file

has anyone experience log file issues on 02Dec2025 and how can this be explained?

I’m not sure it’s a logging problem, SoC jumps tend to suggest a battery pack that hasn’t yet achieved balance, the BMS is seeing one of the battery pack cells voltage fall and is re-calculating the SoC (which is a virtual calculation based on all pack cell voltages)

On new systems it can take a couple of 100>10>100 charge cycles before the pack is balanced, if a battery is added to the pack and the SoC is different to the other batteries (Fox recommend all batteries should be added at 50% SoC +/- 3%), then that can take several weeks for them to effectively balance.

It is also possible (but highly unlikely) that one of the batteries has an issue in which case after several weeks of normal operation and attempted cycling if the SoC still jumps that should be investigated further.

Hi Dave and thanks heaps for the reply....

My issue is not SOC.

My issue is that the log file that I exported from FOX Cloud V2 for Wed 02Dec2025 (see attached PLANTaee0b39c-db9d-4968-95f8-cab118853f3d_20251202_27.zip) is inaccurate and doesn't even lineup with FOX Cloud V2 satistical graph (see Cloud Usage Graph.jpg)

According to the export log file, I exported 28.32KW to the grid.
Yet the Fox Cloud usage graph and Amber data show that I exported 34.2KW to the grid

I know the graph data is correct because it lines up with what Amber has recorded.

I was hoping that by raising this issue, someone from Fox would review the data and explain/fix the inaccuracy

I'm also waiting for a reply on something similar (incorrect accounting of charge/discharge energy in a battery system). No reply yet.

I would still suggest creating a ticket if you haven't already done so.