SolaxModbus: load_first mode disables battery discharge (EMS rate written as 0)

[bess-agent]

Bug

SolaxModbusGrowattController.apply_period() calls _write_period_to_hardware(controller, False, 0) for all modes, including load_first.

_write_period_to_hardware calls set_discharging_power_rate(discharge_rate). When discharge_rate=0 is written to the EMS discharging rate register, the inverter disables discharge entirely — defeating Load First's inverter-native discharge control.

Impact

Any period whose strategic intent maps to load_first (IDLE, LOAD_SUPPORT, SOLAR_STORAGE) will have the EMS discharge rate zeroed, preventing the battery from discharging during those periods.

Root Cause

In core/bess/solax_modbus_growatt_controller.py (apply_period), _write_period_to_hardware was called unconditionally after the TOU segment update block, regardless of mode.

Fix

Gate _write_period_to_hardware on mode != "load_first". Load First relies on inverter-native discharge control; the EMS rate register must not be touched.

Fix is on branch fix/solax-ems-discharge-rate with a regression test.

[bess-manager-claude-bot]

Thanks for the detailed report — it clearly describes the control flow and impact. To proceed to code-level analysis, please attach a debug log from a system where the issue occurs. Navigate to System Health → Download Debug Report and paste the JSON in a comment. This log captures configuration, sensor state, and active mode, which Stage 2 uses to verify the root cause path. Reply @claude-bot analyze once the log is attached.