WIT Inverter Control Guide¶

Understanding WIT Control Architecture¶

WIT (Wireless Inverter Technology) series inverters (4000-15000TL3) use a fundamentally different control model compared to SPH/SPF hybrid inverters. Understanding this difference is critical for stable battery management.

Critical Difference: VPP Protocol vs Legacy Protocol¶

SPH/SPF/MOD Models (Legacy Protocol)¶

Direct mode control: Can set priority mode (Load First/Battery First/Grid First) via Modbus
Persistent settings: Mode changes remain active until changed again
Simple control: Write to register, mode changes immediately
Register range: 1000+ (holding registers)

WIT Models (VPP Protocol)¶

Time-limited overrides: Control commands are temporary (duration-based)
Read-only base mode: Register 30476 (priority_mode) shows TOU schedule default, cannot be changed via Modbus
VPP remote control: Registers 201-202 and 30407-30409 for temporary overrides
Register range: 30000+ (VPP protocol range)

WIT Control Model Explained¶

What You CAN Do:¶

✅ Read the current priority mode (register 30476) - shows TOU schedule default ✅ Override battery behavior temporarily using VPP remote control ✅ Set charge/discharge power and duration (30407-30409) ✅ Monitor all battery/inverter parameters

What You CANNOT Do:¶

❌ Change the base priority mode via Modbus (register 30476 is read-only) ❌ Permanently set battery mode externally ❌ Disable TOU schedule via Modbus ❌ Use SPH-style persistent mode control

Register 30476: Priority Mode (READ-ONLY)¶

Common Misconception: This register can be written to change WIT operating mode.

Reality: On WIT inverters, register 30476 is read-only and shows: - The default mode used outside configured TOU periods - What mode the inverter will return to when remote overrides expire - Current TOU period mode if a schedule is active

Values: - 0 = Load First (default) - 1 = Battery First - 2 = Grid First

To change this value: Must be configured via inverter display panel or manufacturer app, NOT Modbus.

VPP Remote Control Registers (Proper WIT Control)¶

Control Authority (Register 30100)¶

Purpose: Master enable/disable for VPP remote control Values: 0 = Disabled, 1 = Enabled Note: Must be enabled before using remote power control

Remote Power Control (Registers 30407-30409)¶

Register 30407: Remote Power Control Enable¶

0 = Disabled
1 = Enabled (activates timed override)

Register 30408: Charging Time (Duration)¶

Range: 0-1440 minutes (0-24 hours)
How long the override remains active
Timer starts when register 30407 is set to 1

Register 30409: Charge/Discharge Power¶

Range: -100 to +100 (signed integer)
Negative values = Discharge battery to grid
Positive values = Charge battery from grid
0 = No charge/discharge (passthrough)

Legacy VPP Registers (Registers 201-202)¶

Register 201: Active Power Rate¶

Range: 0-100%
Maximum power level for the operation

Register 202: Work Mode¶

0 = Standby
1 = Charge (from grid)
2 = Discharge (to grid)

Proper WIT Control Patterns¶

Pattern 1: Temporary Grid Charging (2-hour window)¶

Enable control authority (if not already enabled)
Set charging time: 120 minutes (register 30408)
Set charge power: +50 (50% charge, register 30409)
Enable remote control: 1 (register 30407)
After 2 hours, inverter automatically returns to base mode

Pattern 2: Peak Shaving (discharge during high rates)¶

Set discharge power: -80 (80% discharge, register 30409)
Set duration: 180 minutes (3 hours, register 30408)
Enable remote control: 1 (register 30407)
Inverter discharges battery for 3 hours, then returns to normal

Pattern 3: Cancel Active Override¶

Set remote control enable: 0 (register 30407)
Inverter immediately returns to base mode (TOU schedule or priority_mode default)

Common Problems and Solutions¶

Problem: Power Oscillation / Looping Behavior¶

Symptoms: Battery rapidly switches between charging and discharging

Causes: 1. Home Assistant automation writing to WIT controls too frequently 2. Multiple automations conflicting (TOU + manual control) 3. No rate limiting on control changes 4. Trying to write to read-only register 30476

Solutions: - ✅ Use v0.4.6+ which includes 30s rate limiting - ✅ Consolidate control logic into single automation - ✅ Use time-based overrides with appropriate durations - ✅ Don't write to register 30476 (it's read-only on WIT)

Problem: Control Changes Don't Persist¶

Symptoms: Battery mode changes but reverts quickly

Cause: This is expected WIT behavior - overrides are time-limited

Solution: - ✅ Set appropriate duration in register 30408 - ✅ Don't expect permanent mode changes like SPH inverters - ✅ Use longer durations for extended operations

Problem: Conflicts Between TOU and Remote Control¶

Symptoms: Inverter doesn't follow remote commands during certain times

Cause: TOU schedule periods override remote control

Solution: - ✅ Check TOU schedule configuration on inverter - ✅ Schedule remote overrides outside TOU periods - ✅ Or disable TOU schedule entirely (via inverter panel)

Rate Limiting (v0.4.6+)¶

To prevent oscillation and instability, v0.4.6 introduces 30-second rate limiting on WIT control writes:

How it works: - Integration tracks last write time for each WIT control register - If you try to write within 30 seconds of previous write, request is blocked - Warning logged: "Rate limit: WIT control writes must be 30s apart"

Impact: - ✅ Prevents rapid automation loops - ✅ Gives inverter time to respond to commands - ✅ Reduces Modbus traffic and errors - ⚠️ May delay rapid manual control changes (intentional)

Bypass: Wait 30 seconds between control changes (this is good practice anyway)

Control Conflict Detection (v0.4.6+)¶

The integration now detects potential control conflicts:

Checks: 1. Multiple VPP remote control registers active simultaneously 2. TOU periods configured while remote control is active 3. Rapid control changes (rate limiting violations)

Actions: - Warning logged to Home Assistant logs - User notified via persistent notification (if enabled) - No automatic remediation (user must resolve)

Migration from SPH/SPF Control Logic¶

If you're used to SPH/SPF inverters and moving to WIT, here are key changes:

SPH/SPF Approach (doesn't work on WIT):¶

# DON'T DO THIS ON WIT
automation:
  - alias: "Set Battery First Mode"
    action:
      - service: number.set_value
        target:
          entity_id: select.growatt_priority_mode
        data:
          option: "Battery First"  # Won't persist on WIT!

WIT Approach (correct):¶

# DO THIS ON WIT
automation:
  - alias: "Discharge Battery for 3 Hours"
    action:
      # Set duration
      - service: number.set_value
        target:
          entity_id: number.growatt_remote_charging_time
        data:
          value: 180  # 3 hours

      # Set discharge power
      - service: number.set_value
        target:
          entity_id: number.growatt_remote_charge_discharge_power
        data:
          value: -80  # 80% discharge

      # Enable remote control
      - service: switch.turn_on
        target:
          entity_id: switch.growatt_remote_power_control

Recommended WIT Control Setup¶

1. Enable VPP Control Authority (One-time setup)¶

service: switch.turn_on
target:
  entity_id: switch.growatt_control_authority

2. Create Helper Input Numbers (for automation logic)¶

# configuration.yaml
input_number:
  battery_override_duration:
    name: Battery Override Duration
    min: 0
    max: 1440
    step: 30
    unit_of_measurement: "min"

  battery_override_power:
    name: Battery Override Power
    min: -100
    max: 100
    step: 10
    unit_of_measurement: "%"

3. Create Automation Template¶

automation:
  - alias: "WIT Battery Override"
    trigger:
      - platform: state
        entity_id: input_boolean.battery_override_active
        to: 'on'
    action:
      # Set duration from helper
      - service: number.set_value
        target:
          entity_id: number.growatt_remote_charging_time
        data:
          value: "{{ states('input_number.battery_override_duration') | int }}"

      # Set power from helper
      - service: number.set_value
        target:
          entity_id: number.growatt_remote_charge_discharge_power
        data:
          value: "{{ states('input_number.battery_override_power') | int }}"

      # Wait for rate limit (v0.4.6+)
      - delay:
          seconds: 2

      # Enable override
      - service: switch.turn_on
        target:
          entity_id: switch.growatt_remote_power_control

Troubleshooting¶

Enable Debug Logging¶

# configuration.yaml
logger:
  default: info
  logs:
    custom_components.growatt_modbus: debug

Check for Rate Limit Warnings¶

Look for: [WIT CTRL] Rate limit: WIT control writes must be 30s apart

Verify Control Authority Status¶

Check entity: switch.growatt_control_authority (must be ON)

Monitor Active Overrides¶

switch.growatt_remote_power_control (shows if override active)
number.growatt_remote_charging_time (shows remaining duration)
number.growatt_remote_charge_discharge_power (shows current power setting)

Summary¶

Key Takeaways: 1. WIT uses VPP protocol - time-limited overrides, not persistent mode changes 2. Register 30476 (priority_mode) is read-only on WIT 3. Use registers 30407-30409 for proper WIT control 4. Rate limiting (30s) prevents oscillation (v0.4.6+) 5. TOU schedule and remote control can conflict 6. Design automations for time-based operations, not permanent modes

Best Practices: - ✅ Set appropriate duration for all overrides - ✅ Wait 30+ seconds between control changes - ✅ Use single automation for battery control (avoid conflicts) - ✅ Monitor logs for rate limit warnings - ✅ Test control changes during non-TOU periods first