# lumapu/ahoy

Various tools, examples, and documentation for communicating with Hoymiles microinverters

Repository: https://github.com/lumapu/ahoy
Canonical: https://ross.abutalabs.com/products/lumapu-ahoy
Homepage: https://ahoydtu.de
Language: C++
License: NOASSERTION
License Family: other
Topics: arduino, asyncwebserver, esp32, esp8266, nrf24, cmt2300, hoymiles, mqtt, pv
Last push: 2025-08-12T20:41:51+00:00

## Health v2 (maintenance only)
Score: 42/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 36, release rhythm 18, longevity 100
- inputs: {"age_days": 1629, "days_push": 386, "days_rel": 386, "gap_med": 156, "n_releases_24m": 2}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1012, forks 237 (observed 2026-08-28T04:03:13.394866+00:00)

## What it is
AhoyDTU is open-source firmware for ESP32/ESP8266 that communicates with Hoymiles microinverters via radio (NRF24/CMT2300A), providing a local web interface, MQTT, and REST/JSON APIs to read live solar data and set parameters like power limits. It acts as a cloud-free replacement for the vendor DTU and integrates with smart home systems like Home Assistant and ioBroker.

## Use cases
- monitor my Hoymiles solar microinverter without the cloud
- read real-time power, current, and daily energy from HM/HMS/HMT inverters
- set a power limit on my inverter for zero export to the grid
- integrate solar inverter data into Home Assistant via MQTT
- visualize PV production in Grafana or InfluxDB
- build my own DIY DTU for Hoymiles inverters with an ESP32
- troubleshoot individual solar panels by monitoring per-input voltage and current

## When to choose
- you have a supported Hoymiles MI, HM, HMS, or HMT microinverter and want local, cloud-free monitoring
- you want MQTT/REST integration into an existing smart home setup
- you need inverter control such as dynamic power limiting for zero export
- you want per-panel diagnostics to optimize panel orientation or detect shading

## When to avoid
- you have an HMS-xxxxW WiFi inverter with an integrated DTU, which is not supported
- you need a commercially licensed solution - the project is CC BY-NC-SA (non-commercial)
- you need a certified, plug-and-play commercial DTU product rather than DIY firmware on your own ESP hardware

## Facets
- artifact type: application
- maturity: active
- function: monitoring, web-framework, iot, embedded
- domain: iot, energy, self-hosted, hardware
- platform: iot, embedded, self-hosted
- tags: hoymiles, microinverter, solar, pv-monitoring, dtu, nrf24, cmt2300a, zero-export, firmware, smart-home-integration, mqtt, automation, esp8266

## Member repositories
- lumapu/ahoy (main) score 42

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:13.394866+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:11:46.246657+00:00, confidence not recorded.
  - readme: https://github.com/lumapu/ahoy (fetched 2026-08-28T04:03:13.394866+00:00, sha 8d1435a1dade)
  - homepage: https://ahoydtu.de (fetched 2026-08-29T13:11:23.842447+00:00, sha c5b2d1a7780f)
  - site_page: https://ahoydtu.de/web_install (fetched 2026-08-29T13:11:23.845017+00:00, sha 79d1c04886a6)
  - site_page: https://ahoydtu.de/faq (fetched 2026-08-29T13:11:23.847320+00:00, sha 3e0f273ea658)
- Data as of 2026-08-30T08:39:29.467469+00:00.