Dacia Spring EVCC MQTT OBD-II ELM327 Monitor

This project is a Python-based tool for monitoring and interacting with a Dacia Spring electric vehicle via an ELM327 OBD-II adapter. It connects to the car's OBD-II port (using an ELM327-compatible device over TCP), reads battery and charging information, and can publish this data to an MQTT broker or print it to the console. It also integrates with evcc to monitor and control charging sessions.

Background & Motivation

There is no official API for the Dacia Spring’s charging state - only Renault’s "My Dacia" mobile app. Reverse-engineered libraries often face strict rate limits and break when APIs change. This project bypasses those issues by using a wireless OBD-II adapter to read charging and battery data directly from the vehicle.

The main goal is to optimize PV charging with evcc. Since the Dacia Spring doesn’t automatically resume charging after long pauses, polling the OBD-II port wakes the high-voltage (HV) battery system to allow charging. To reduce HV system wear, polling is limited to when the charger is connected, during charging, or if charging fails to resume; otherwise, it runs only every few hours to monitor battery status and detect drain.

Features

• Reads 12V battery voltage, high-voltage battery State of Charge (SoC), and State of Health (SoH).
• Publishes readings to MQTT for integration with home automation or monitoring systems.
• Optionally connects to an evcc instance to synchronize charging state.
• Designed for use with Dacia Spring (Renault K-ZE platform) but may be adaptable to similar vehicles.

What You Can Do With It

• Monitor your Dacia Spring's battery status remotely.
• Integrate car battery and charging data into your smart home or energy management system via MQTT.
• Automate or optimize charging using evcc integration.

Adapter Compatibility

While in theory any network-enabled OBD-II adapter that supports the ELM327 protocol should work, this project has been developed and is in active use with a MeatPi WiCAN adapter. This project is not affiliated with MeatPi, but I know that it works and the firmware is open-source, which is cool.

Getting Started

Prerequisites

• Python 3.9+ (developed and tested under Python 3.12)
• ELM327 OBD-II adapter (WiFi/TCP recommended)
• Dacia Spring (or compatible Renault K-ZE platform vehicle)

Installation

1. Clone this repository:

   git clone https://github.com/capi/springwatch-elm327-evcc.git
   cd <repo-name>

2. Install dependencies:

   pip install -r requirements.txt

Configuration

• Copy .env.template to .env and fill in your settings (MQTT broker, ELM327 host/port, etc.).
• See comments in .env.template for details on each variable.

Usage

Run the main script:

python wican-elm327-evcc-mqtt-dacia.py

Docker

You can build and run this project using Docker.

Build the Docker image

docker build -t springwatch-elm327-evcc .

Run the container

Replace environment variables and volume mounts as needed for your setup (check .env.template for additional variables to set.):

docker run --rm \
  --name springwatch \
  -e MQTT_BROKER_HOST=your-mqtt-broker-host \
  -e MQTT_BROKER_PORT=your-mqtt-broker-port \
  -e ELM327_HOST=your-obd-host \
  -e ELM327_PORT=your-obd-port \
  springwatch-elm327-evcc

You may need to adjust device access or network settings depending on your OBD-II adapter and MQTT broker configuration.

Docker Compose

You can also use Docker Compose for easier management. Create a docker-compose.yml file like this:

services:
  springwatch:
    image: springwatch-elm327-evcc
    env_file:
      - .env
    restart: unless-stopped

Make sure your .env file contains the required environment variables (see .env.template).

Build and start the service:

docker-compose up --build -d

Python Version

This project requires Python 3.9 or newer. It was developed and tested under Python 3.12. Older versions (such as Python 3.8) are not supported due to usage of newer language features.

Project Structure

• wican-elm327-evcc-mqtt-dacia.py: Main entry point.
• springwatch/: Core logic (ELM327 communication, MQTT, polling, etc.).
• requirements.txt: Python dependencies.
• .env.template: Example environment configuration.

License

MIT License. See LICENSE.