evcc MQTT Listener for Tesla Powerwall

This project listens to evcc state updates via MQTT, to control the discharge of a Tesla Powerwall. The powerwall is swichted between two "logical" modes BACKUP_ONLY and STANDBY (normal operations). To achieve this behavior the backup reserve percentage of the PW is controlled. BACKUP only mode simply means setting the reserve percentage to 100%, effectively preventing any discharge (unless grid fails). STANDBY mode is achieved by resetting the reserve percentage to a configured default value of your installation. Usually this value is configured via the slider in the Tesla App.

decision logic

• as long as evcc is not charging, put Powerwall in Standby
• If evcc is charging, check the charge mode.
• If charge mode is fast put PW into BACKUP only mode.
• Alternatively, if charge mode is PV and at the same time the planner is active, also put PW into BACKUP only mode

Limitations

• only supports a single loadpoint
• overwrites backup reserve percentages set via the Tesla App

Configuration

You need to create a configuration, an example template can be found in the config folder. At a minimum you need to adjust the mqtt.broker.url, and you need to provide an oauth refresh token for your Tesla account (in tesla.refreshToken). Optionally, you may also want to adjust the tesla.backupReservePercent to match your current settings in the Tesla App. The configuration file needs to be mounted into the container as /usr/src/app/config/default.json.

Running

The docker image can be used in a compose file (e.g. together with evcc) as shown below.

  evcc-mqtt-listener:
    container_name: evcc-mqtt-listener
    image: ghcr.io/grimmimeloni/evcc-mqtt-listener:main
    volumes:
      - ./evcc-mqtt-config/default.json:/usr/src/app/config/default.json
    restart: unless-stopped