🔋 FoxESS Battery Details now working in app — hardware-proven EP-Series CAN protocol

[hughes4262]

Hi @dalathegreat

I’ve been working on a standalone FoxESS EP-Series CAN protocol for Battery-Emulator and have now reached a hardware-proven checkpoint that I wanted to share with you.

The work has been developed from genuine FoxESS EP12 CAN captures, Fox manager-firmware analysis and testing on a real FoxESS KH-series inverter using Battery-Emulator.

The current v67 checkpoint has been hardware-tested with:

• charging and discharging working correctly
• the FoxESS Battery Details page now fully populated and working, including remaining capacity/energy, nominal battery energy, SOH, Battery Cycles, Daily/Total Charged and Discharged values, and separate minimum/maximum cell-temperature monitoring in the app
• cumulative charged and discharged energy working through 0x187A
• an independent cumulative charged-capacity path proven through 0x1879
• equivalent-cycle movement through 0x1875 proven from 0 to 1
• the additional 0x1878 and 0x1900–0x1909 EP-Series frames mapped and documented to their current evidence level
• generic Battery-Emulator readiness logic rather than battery-specific logic

I’ve documented the frame mappings, evidence levels, hardware tests, Fox’s observed Total Charged fall-back behaviour, commissioning considerations and the areas that are still unresolved.

The main remaining release-quality issue identified during hardware testing is persistence of the cumulative installation counters. They are currently RAM-only, so a Battery-Emulator reboot or firmware reflash resets the locally derived values while Fox retains its previous baseline. In testing, this produced negative Daily Charged/Discharged values and could also cause Fox’s Total Charged fallback to become active again. I’ve documented the behaviour and left the best persistence approach open for upstream discussion..

Repository:
https://github.com/hughes4262/FoxESS-EP-Series-CAN-Protocol

Many thanks for Battery-Emulator — all of the implementation and hardware testing was made possible by using it as the underlying battery integration and CAN framework.

I’d be interested in your thoughts on the protocol and, particularly, where you would prefer the persistent counter state to live if this is eventually integrated upstream.

— Hughes4262