HeidelBridge is a firmware for ESP32 microcontrollers. It allows you to bring your Heidelberg wallbox into your WiFi network. This is done by turning your wallbox into a Daheimladen compatible device. This way the wallbox can easily be integrated into home energy management systems like evcc.
You only need two components for this project: an ESP32 microcontroller and a MAX485 module. Both are available in large quantities and at reasonable prices on the Internet. You will also need a breadboard and a few jumper wires. All in all, it shouldn't cost you more than 10$.
Parts list:
- ESP32 microcontroller*
- MAX485 breakout board
- 6 jumper wires
- A breadboard
This should be enough for quickly putting together a fully functioning prototype. Of course a well designed PCB would be much nicer, but this is still work in progress. Once the design is ready, the schematics will be available right here.
* This project is currently based on the classic ESP32. It has not been built/tested for newer models, like the S2 and C6.
To compile this project you will need to install VS Code and the PlatformIO extension. Both are available for free for Linux, MacOS and Windows.
- Start by cloning or downloading this repository.
- Change
board = ...in platformio.ini to match the ESP32 board you are actually using. - Copy the file
Credentials.cpp.templatetoCredentials.cpp. - Change the SSID and password in
Credentials.cppto match your home network settings. - If you want to use MQTT, also insert your MQTT server's address and your user name / password (can be left empty if not required).
- Compile the project.
- Now connect your ESP32 via USB and upload the firmware.
- Disconnect the wallbox from the power supply.
- Open the housing.
- Set DIP switch S4 pin 4 to 1 (this sets the Modbus ID to 1).
- Set DIP switch S6 pin 2 to 1 (this enables the 120 Ohm termination).
The hardware connections are very simple:
- ESP32's GND to MAX485-board GND
- ESP32's 3.3 V to MAX485-board VCC
- ESP32 pin 18 to MAX485-board RO pin
- ESP32 pin 19 to MAX485-board DI pin
- ESP32 pin 21 to MAX485-board DE+RE pins
- MAX485-board A terminal to Heidelberg wallbox A terminal
- MAX485-board B terminal to Heidelberg wallbox B terminal
Important
Please make sure that you set up your HeidelBridge before adding it to evcc. Evcc won't start up, if it can't find your HeidelBridge!
Adding your HeidelBridge to evcc is very straight forward. Start by defining a new charger:
chargers:
- name: heidelberg_ec
type: template
template: daheimladen-mb
host: 192.168.178.133 # IP address or hostname
port: 502 # Port (optional)
Next, add a loadpoint:
loadpoints:
- title: Heidelberg EC
charger: heidelberg_ec
mode: off
guardduration: 5m
Aaaaaand you're done! Start evcc with your new configuration and the HeidelBridge should be there.
HeidelBridge offers a simple MQTT API (see below). It also supports Home Assistant's MQTT auto discovery feature. This way HeidelBridge can easily be added to Home Assistant:
- Make sure the MQTT integration in Home Assistant is enabled.
- Power on your HeidelBridge.
- The HeidelBridge should immediately show up as an MQTT device.
GUI Example:
The following topics are published by HeidelBridge:
| Topic | Unit | Data Type | Description |
|---|---|---|---|
| heidelbridge/version | - | String | The version of the HeidelBridge firmware (e.g. 1.0.0). |
| heidelbridge/build_date | - | String | Build date of the HeidelBridge firmware. |
| heidelbridge/ip_address | - | String | Currently assigned IP address of the HeidelBridge. |
| heidelbridge/is_vehicle_connected | - | Integer | Boolean (0 or 1) indicating if a vehicle is connected. |
| heidelbridge/is_vehicle_charging | - | Integer | Boolean (0 or 1) indicating if a vehicle is charging. |
| heidelbridge/vehicle_state | - | String | 'disconnected', 'connected' or 'charging'. |
| heidelbridge/charging_current_limit | A | Float | Charging current limit in Ampere. |
| heidelbridge/charging_power | W | Float | Momentary charging power in Watt. |
| heidelbridge/failsafe_current | A | Float | Current the wallbox will fall back to in case of a communication error. |
| heidelbridge/energy_meter | kWh | Float | Total charged energy so far. |
| heidelbridge/temperature | °C | Float | Current wallbox PCB temperature. |
| heidelbridge/charging_current/phase1 | A | Float | Momentary charging current on phase 1. |
| heidelbridge/charging_current/phase2 | A | Float | Momentary charging current on phase 2. |
| heidelbridge/charging_current/phase3 | A | Float | Momentary charging current on phase 3. |
| heidelbridge/charging_voltage/phase1 | V | Float | Momentary charging voltage on phase 1. |
| heidelbridge/charging_voltage/phase2 | V | Float | Momentary charging voltage on phase 2. |
| heidelbridge/charging_voltage/phase3 | V | Float | Momentary charging voltage on phase 3. |
| heidelbridge/internal/uptime | s | Integer | Total time this HeidelBridge has been up and running. |
| heidelbridge/internal/wifi_disconnects | - | Integer | Total number of WiFi connection losses since start. |
| heidelbridge/internal/mqtt_disconnects | - | Integer | Total number of MQTT connection losses since start. |
| heidelbridge/internal/modbus_read_errors | - | Integer | Total number of Modbus RTU read errors since start. |
| heidelbridge/internal/modbus_write_errors | - | Integer | Total number of Modbus RTU write errors since start. |
The following topics are subscribed by HeidelBridge. Use these to control your wallbox:
| Topic | Unit | Data Type | Description |
|---|---|---|---|
| heidelbridge/control/charging_current_limit | A | Float | Charging current limit in Ampere. |
❤️ Help is welcome! Do you own a Heidelberg Energy Control wallbox? Are you a Modbus expert? Do you have ideas for improvements? Did you find a bug? Feel free to review the code, create pull requests, open issues or contact me directly.
The following assets and libraries are used by this project: