Dimension scores are derived from public data and fields; weighted into the composite. Reference only.
AhoyDTU is an open-source firmware for reading data from Hoymiles microinverters. The project is hosted on GitHub and licensed under CC-BY-NC-SA 4.0. It runs on hardware such as ESP32 or ESP8266, communicates with inverters via NRF24L01+ or CMT2300A wireless modules, and provides a real-time web interface on the local network over WLAN. It is not positioned as a cloud-based energy platform, but rather as a local DTU that forwards inverter data to home automation, monitoring, and visualization systems.
According to the main documentation, AhoyDTU supports multiple generations of Hoymiles devices, including MI, HM, HMS, and HMT, and it also mentions support for some TSOL inverters. However, the HMS-xxxxW series cannot currently be read because it has an integrated DTU and no traditional wireless module. AhoyDTU can display AC parameters as well as the DC voltage, current, power, and energy output of each panel input, making it useful for troubleshooting shading, cabling, or module issues, and for optimizing panel tilt and orientation. The system can manage up to 16 inverters, depending on the configuration.
AhoyDTU is fairly developer-friendly: it includes built-in MQTT support and provides a REST API. MQTT can send collected values to a specified broker, even at second-level intervals. The official documentation also mentions successful integrations with ioBroker and Home Assistant, with data visualization available through Grafana. For long-term storage, external components such as Mosquitto, InfluxDB, or MySQL are required. There is also a special firmware build that includes a Prometheus Endpoint, which is suitable for users who already have a monitoring stack.
The firmware itself is open source, and the main text does not mention any software fees. The hardware mainly consists of an ESP32/ESP8266 plus a wireless module; the page states that the cost is around 15 euros, making it highly cost-effective. All data is processed within the local network, with no cloud connection required. This is appealing for residential solar users who value privacy, reliability, and offline availability.
The main advantages are low cost, no cloud dependency, open interfaces, strong compatibility with smart home ecosystems, and access to panel-level data. The drawbacks are that users need to assemble and solder the hardware themselves; HMS/HMT support was previously released as a Development Preview, so there may be stability risks; and AhoyDTU itself does not store historical data, requiring an external system for that. In addition, running multiple DTUs in parallel may cause communication conflicts. It is best suited to hands-on solar users, Home Assistant/ioBroker enthusiasts, and anyone interested in zero feed-in setups and fine-grained energy monitoring.
The main documentation does not provide information about network access, payments, or local services in China. Since the project relies on GitHub for firmware downloads, the experience for users in mainland China may be affected by local network conditions. Alternatives include OpenDTU, the official Hoymiles DTU, or Home Assistant-based energy monitoring setups.
⚠ This review is compiled from public sources and does not constitute a purchase recommendation. Verify all facts on the vendor's official site. Verify on ahoydtu.de official site.
ahoydtu.de is an Germany Energy provider. TG4G tracks its product information, an overall rating of 7.0/10, and a China-accessibility score of Workable. Click "Visit Official Site" to reach ahoydtu.de directly.