To read Hoymiles inverters there is a nice project called OpenDTU that uses an ESP32 to communicate with them. This is a ready-to-use SMD PCB with an ESP32 (ESP32-D0WDQ6) and a NRF24L01+ radio module to run OpenDTU (or Ahoy) firmware on it.

Specifications:

• Size: 50mm x 40mm with 2mm mounting holes
• Processor: ESP32 on ESP32-WROOM-32 module (Wi-Fi, Bluetooth®, Bluetooth LE)
• Nordic 2.4GHz NRF24L01+
• Power Input: 5v via USB-C Connector
• Onboard CH340C USB to serial interface for programming
• Read live data from inverter
• Show inverters internal event log
• Supports up to 10 inverters
• MQTT support (with TLS)
• Home Assistant MQTT Auto Discovery support
• Displays (SSD1306, SH1106, PCD8544)
• MicroSD card slot to save important data offline (e.g. as a CSV file)
• Configuration management (export / import configurations)

NRF24L01+ Configuration:

Attention: We recommend a power supply with 5V and at least 2A for our OpenDTU. We are currently selling the remaining boards from the first batch. If there is enough interest, we will order a new batch with more parts.