ABB Terra AC Wallbox - Home Assistant Integration

Custom Home Assistant integration for ABB Terra AC W11 wallbox via Modbus TCP.

Features

Entities Created

Sensors:

• Charging Current (L1, L2, L3, Total)
• Voltage (L1, L2, L3)
• Active Power (W)
• Energy Delivered (Wh)
• Charging State (with IEC 61851-1 state names)
• Current Limit Setting
• Max Current
• Error Code
• Socket Lock State
• Communication Timeout
• Serial Number
• Firmware Version

Controls:

• Number Slider (0-16A) - Set charging current limit

  • Set to 0A to pause charging
  • Slide to desired amperage to charge at that rate

• Start/Pause Switch - Quick start/pause control

  • ON = Start charging at 6A (default)
  • OFF = Pause charging (0A)

• Stop Button - Emergency stop

  • Sends STOP command (register 16645 = 1)
  • Use for immediate charging termination

Services:

• abb_terra_ac.set_current_limit - Set current limit (0-16A)
• abb_terra_ac.start_charging - Start charging with optional current (default 6A)
• abb_terra_ac.stop_charging - Emergency stop

Installation

1. Enable Local Controller Mode

On your ABB Terra AC wallbox:

1. Download and install the Terra Config app on your phone
2. Connect to the wallbox via Bluetooth
3. Navigate to settings
4. Enable "Local Controller" mode
5. Connect wallbox to your network via Ethernet cable (WiFi not supported for Modbus)

2. Install the Integration

Copy the custom_components/abb_terra_ac folder to your Home Assistant custom_components directory:

homeassistant/
  └── custom_components/
      └── abb_terra_ac/
          ├── __init__.py
          ├── button.py
          ├── config_flow.py
          ├── const.py
          ├── manifest.json
          ├── number.py
          ├── sensor.py
          ├── services.yaml
          └── switch.py

3. Restart Home Assistant

Restart Home Assistant to load the integration.

4. Add Integration

1. Go to Settings → Devices & Services
2. Click + Add Integration
3. Search for "ABB Terra AC Wallbox"
4. Enter configuration:
   • Host: IP address of your wallbox (e.g., 192.168.1.100)
   • Port: 502 (default Modbus TCP port)
   • Unit ID: 1 (default)

Usage

Basic Control

Using the Slider:

• Drag slider to desired amperage (0-16A)
• Set to 0A to pause charging
• Wallbox will adjust charging rate in real-time

Using the Switch:

• Turn ON to start charging at 6A
• Turn OFF to pause (0A)

Emergency Stop:

• Press the "Stop Charging" button
• Sends immediate STOP command to wallbox

Automation Examples

Charge at Solar Surplus:

automation:
  - alias: "Charge EV with Solar Surplus"
    trigger:
      - platform: state
        entity_id: sensor.solar_surplus_power
    action:
      - service: abb_terra_ac.set_current_limit
        data:
          current: >
            {{ (states('sensor.solar_surplus_power') | float / 230 / 3) | round(0) | min(16) | max(0) }}

Stop Charging at High Grid Price:

automation:
  - alias: "Stop EV Charging at Peak Price"
    trigger:
      - platform: numeric_state
        entity_id: sensor.electricity_price
        above: 0.30
    action:
      - service: abb_terra_ac.stop_charging

Smart Charging Schedule:

automation:
  - alias: "Start EV Charging at Night"
    trigger:
      - platform: time
        at: "23:00:00"
    action:
      - service: abb_terra_ac.start_charging
        data:
          current: 16  # Full speed

Technical Details

Register Map

Read Registers (0x4000 - 0x4020):

• Serial Number, Firmware, Max Current
• Error Code, Socket Lock, Charging State
• Current Limit, Actual Current (L1/L2/L3)
• Voltage (L1/L2/L3)
• Active Power, Energy Delivered
• Communication Timeout

Write Registers:

• 0x4100 (16640): Set Current Limit (32-bit, mA)
• 0x4105 (16645): Start/Stop Command (0=START, 1=STOP)

Charging States (IEC 61851-1)

• 0: Idle (State A) - No vehicle connected
• 1: EV Connected - Pending Auth (State B1)
• 2: EV Connected - Ready (State B2)
• 3: EV Ready - No PWM (State C1)
• 4: Charging (State C2)
• 5: Other

Important Notes

• Only ONE Modbus connection allowed at a time
• Modbus only works over Ethernet, not WiFi
• Minimum charging current: 6A (per IEC 61851-1)
• Setting current below 6A pauses charging
• STOP button sends actual STOP command (different from pause)
• Default polling interval: 5 seconds

Troubleshooting

Integration won't connect:

• Verify "Local Controller" mode is enabled in Terra Config app
• Check wallbox is connected via Ethernet (not WiFi)
• Ping wallbox IP address to verify network connectivity
• Ensure no other Modbus clients are connected

Current limit not changing:

• Check charging state sensor shows state 4 (charging)
• Car must be connected and authenticated (badge tap)
• Some cars may require manual authorization to start charging

Car won't start charging:

• Tap badge to authenticate on wallbox
• Check car is not set to scheduled charging
• Verify car's charge limit is not reached
• Try using STOP button, wait 5 seconds, then use Start/Pause switch

Credits

Integration developed based on testing with ABB Terra AC W11 wallbox (firmware 1.8.34).

Register discovery and validation performed using Python scripts with pymodbus library.