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


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


This project was started from this discussion ( 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.


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

Github Discussions Discord Chat

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.

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  1. Data Transfer Unit