OpenDTU: local ESP32 gateway for Hoymiles solar microinverters
Replace the cloud-tied Hoymiles DTU with an ESP32 and a radio module to read and limit your solar microinverters locally.
Photos
Photos: tbnobody
Key Facts
- Chip: ESP32 or ESP32-S3
- Radio: NRF24L01+ (HM) or CMT2300A (HMS/HMT)
- Inverters: Hoymiles, TSUN, Solenso
- Output: web API, Home Assistant discovery, Prometheus
About This Project
OpenDTU replaces the official Hoymiles DTU, the telemetry gateway that sends microinverter data to the cloud, with an ESP32 you build yourself. It started on Mikrocontroller.net, where the Hoymiles radio protocol was reverse-engineered, and it now talks to Hoymiles, TSUN and Solenso inverters. The radio module depends on the inverter: the HM series needs an NRF24L01+ and the HMS/HMT series needs a CMT2300A. The docs suggest a common ESP32 DevKit to start, with Ethernet/PoE boards like the Olimex ESP32-POE also supported, a 5V 1A supply, and optional display and LEDs. Pins are free to wire and described in a device profile you upload. Data is served through a web API, with Home Assistant auto discovery and Prometheus metrics.
Source & Attribution
Bill of Materials
Parts list
5 parts · 3 linked
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Not included: 3D-printed case, wire, solder, USB cable
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