SolarInverterLimiter

ESP32 RS485 Solar Inverter Limiter

This project is an ESP32-based solar inverter limiter that can be used to limit the power output of a solar inverter to a specific value. The project uses an ESP32 microcontroller and an RS485 module to communicate with the inverter.

Features

• ESP32-based solar inverter limiter
• RS485 communication with solar inverter
• Publishes power and sensor values via MQTT
• Configurable power output limit
• Web-based settings UI (ConfigManager)

Hardware Requirements

• ESP32 microcontroller
• RS485 module (e.g. MAX485 or similar)

How to use

1. Build and upload with PlatformIO:

• Build: pio run -e usb
• Upload: pio run -e usb -t upload

2. On first boot (or when WiFi SSID is empty) the device starts an access point:
3. Connect to the AP and open the web UI (usually http://192.168.4.1/) to configure WiFi/MQTT and other settings.
4. After WiFi is configured the web UI will be available on the device IP in your LAN.

Wiring Diagram

• connect the RS485 module to the ESP32 microcontroller as follows:
• see Wokwi for a wiring example

ESP32 Pin | RS485 Pin
--------- | ---------
GPIO 19   | TXD (Transmitter)
GPIO 18   | RXD (Receiver)
GND       | GND
VCC       | VCC (5V or 3.3V depending on the RS485 module)

Home Assistant Integration

• See the examples in docs/HomeAssistant.yaml and docs/HomeAssistant_Dashboard.yaml.
• Minimal MQTT sensor example (topics depend on the configured MQTT base topic):

mqtt:
  sensor:
    - name: "SolarLimiter_SetValue"
      state_topic: "SolarLimiter/SetValue"
      unique_id: SolarLimiter_SetValue
      device_class: power
      unit_of_measurement: "W"

    - name: "SolarLimiter_GetValue"
      state_topic: "SolarLimiter/GetValue"
      unique_id: SolarLimiter_GetValue
      device_class: power
      unit_of_measurement: "W"

    - name: "SolarLimiter_Temperature"
      state_topic: "SolarLimiter/Temperature"
      unique_id: SolarLimiter_Temperature
      device_class: temperature
      unit_of_measurement: "°C"

    - name: "SolarLimiter_Humidity"
      state_topic: "SolarLimiter/Humidity"
      unique_id: SolarLimiter_Humidity
      device_class: humidity
      unit_of_measurement: "%"

    - name: "SolarLimiter_Dewpoint"
      state_topic: "SolarLimiter/Dewpoint"
      unique_id: SolarLimiter_Dewpoint
      device_class: temperature
      unit_of_measurement: "°C"