Introduction

OpenDTU

Open Source software to talk to Hoymiles solar inverters. It is an alternative to their DTUs¹ which sync everthing into the s-Miles cloud.

Note

You can only use one DTU for a specific inverter. You cannot query a inverter with two DTUs. Mixing up multiple DTUs may lead to an unexpected behavior!

Remarkable features

Read live data from inverter
Show inverters internal event log
Show inverter information like firmware version, firmware build date, hardware revision and hardware version
Show and set the current inverter limit
Show the current grid profile settings
Function to turn the inverter off and on
Supports up to 10 inverters
MQTT support (with TLS)
Home Assistant MQTT Auto Discovery support
Nice and fancy WebApp with visualization of current data
Firmware upgrade using the web UI
Time zone support
Ethernet support
Prometheus API endpoint (/api/prometheus/metrics)
English, german and french web interface
Displays (SSD1306, SH1106, PCD8544)
Status LEDs
Configuration management (export / import configurations)
Dark Theme

Features for developers

The microcontroller part
- Build with Arduino PlatformIO Framework for the ESP32
- Uses a fork of ESPAsyncWebserver and espMqttClient
The WebApp part
- Build with Vue.js and Bootstrap
- Source is written in TypeScript

Background

This project was started from this discussion (Mikrocontroller.net). It was the goal to replace the original Hoymiles DTU (Telemetry Gateway) with their cloud access. With a lot of reverse engineering the Hoymiles protocol was decrypted and analyzed.

Support

For support using OpenDTU you can find us on Github or Discord:

Github Discussions Discord Chat

Donate

The firmware is opensource and free to use!

If you like this project you can show your appreciation by making a small donation. This will help with offsetting the cost of the different hardware devices we support.

Data Transfer Unit ↩