Mode 8 power control never engages

[Animatozeus]

Mode 8 power control never engages (modbus_power_control stays "Disabled") on X3-Hybrid G4, while Mode 1 works fine

Summary

On my SolaX X3-Hybrid G4, Mode 1 remote control works correctly, but Mode 8 never engages. When I trigger any Mode 8 submode, the select is set, the autorepeat counter runs, the trigger fires without error, but sensor.<inverter>_modbus_power_control stays on "Disabled" and the PV is never limited. The inverter keeps exporting at full PV during negative injection prices.

I would like to know whether there is a precondition I am missing (e.g. an installer-menu VPP / external-control setting that must be enabled), or whether this is a known limitation for this inverter/firmware.

System

• Inverter: SolaX X3-Hybrid G4 (rebadged as Qcells Q.VOLT HYB-G3-3P, 8 kW, 3-phase)
• Battery: ~6.2 kWh, Self Use Mode
• Firmware on the inverter LCD: DSP 2.07 / ARM 2.03
  • Note: the integration reports a different version in HA: DSP 1.33 / ARM 1.31-1.08. This mismatch may be a separate reporting issue.
• Integration version: 2026.07.01
• Connection: Waveshare RS485 TO ETH (B), Modbus TCP, gateway mode "Simple Modbus TCP to RTU", 19200/8/N/1, Modbus address 1

What works

• Reads: 100% reliable.
• Mode 1 remote control works: setting remotecontrol_power_control_mode_1 to "Enabled Battery Control" with an active power target and pressing remotecontrol_trigger_mode_1_7 makes active_power_target follow the command and the battery responds.

What does NOT work

• Mode 8 never engages. Tested submodes:
  • "Negative Injection Price"
  • "Mode 8 - PV and BAT control - Duration" (with explicit pv_power_limit_mode_8_9 = 500)
• In both cases:
  • remotecontrol_power_control_mode_mode_8_9 is correctly set to the chosen submode.
  • remotecontrol_autorepeat_remaining counts down (e.g. from 3600), so the loop is armed.
  • The Mode 8 trigger powercontrolmode_trigger_mode_8_9 fires without error.
  • But modbus_power_control stays "Disabled" and never shows "Individual Setting - Duration Mode".
  • PV is not reduced (e.g. stayed at ~9280 W with pv_power_limit set to 500), and grid export continues (~3300 W) during negative injection prices.
• Full parameter set was applied before triggering (pv_power_limit, push_mode_power_mode_8_9, duration_mode_1_8, timeout_mode_1_9, autorepeat_duration_mode_1_9, timeout_next_motion_mode_1_9 = "VPP Off"). No effect.

Additional context

• Standard EEPROM writes (function 0x06), e.g. export_control_user_limit and battery_charge_max_current, are rejected by the inverter with "No response received after 1 retries". Only the 0x10 remotecontrol (Mode 1) writes are accepted. This is why I am relying on Mode 8 for PV limiting rather than the export limit register.

Question

• Is there an installer-menu setting (VPP / external control / remote power control permission) that must be enabled on this inverter before Mode 8 will engage?
• Or is Mode 8 known not to work on this hardware/firmware combination, despite Mode 1 working?

Happy to provide a full debug log if useful. Thanks for the great integration.

[TCWORLD]

Debug log would be useful.

It seems likely that the firmware could be a very old version, or even be customised by Qcells (i.e. same hardware but different firmware).

The Mode 8 loop uses the "new" (well, relatively, last 2 years) VPP register set at 0xA0 (supports mode 0-9).
While the mode 1 loop continues to use the legacy register set at 0x7C (supports mode 0-7 only).

There's currently no feedback - the control loop currently assumes writes were accepted by the inverter. The original legacy register set had no readback facility. The new register set does actually have a readback, though we don't actually use that as it was only recently documented.

[TCWORLD]

From the VPP docs:

So if our reported version number is accurate, your firmware is too old for Mode 8.
If the inverter display reported value is correct I'm at a loss.