Fronius
Austrian solar inverter excellence — PV integration for KNX self-consumption optimisation.
Fronius International (Pettenbach, Austria — founded 1945, solar division since 1992) is one of Europe's leading residential and commercial solar inverter manufacturers. Their Symo GEN24 Plus (three-phase) and Primo GEN24 Plus (single-phase) inverters are widely specified in EU residential and commercial PV systems. Fronius inverters feature Modbus TCP and the Fronius Solar.web API for smart home integration — enabling KNX systems to optimise load dispatch based on real-time solar generation.
Role in our panels
How we use Fronius
Fronius GEN24 inverters support: Modbus TCP (port 502) with a published register map for PV power, grid power, battery state-of-charge, and house consumption; the Fronius Solar.web REST API for cloud-based monitoring; SnapInverter communication interfaces; and the Fronius Smart Meter for household energy monitoring. Their GEN24 Plus range also integrates with Fronius Battery storage (BYD, Fronius GEN24) for self-consumption maximisation.
In our panels, Fronius inverters integrate with KNX for self-consumption optimisation: KNX-Modbus gateway reads Fronius PV generation (W) in real time. KNX logic: when PV excess > threshold → activate KNX loads (EV charger, hot water heating, pool pump). When PV drops → deactivate. Home Assistant provides a more flexible alternative: HA Fronius integration reads Solar.web API → HA energy dashboard → KNX group address with surplus power value → KNX logic activates/deactivates loads. This is the core of smart self-consumption without battery investment.
Used in these project types
Fronius products
Key components we install
Fronius Symo GEN24 Plus 10kW
10kW three-phase string inverter. MPPT tracking, shade management, Modbus TCP, Fronius Solar.web. Battery-ready (Fronius or BYD). The standard inverter for 3-phase residential and light commercial PV systems in EU.
Fronius Primo GEN24 Plus 5kW
5kW single-phase inverter for residential PV. Same GEN24 features as Symo — Modbus TCP, battery-ready, Fronius Smart Meter compatible. For single-phase connections up to 15kWp.
Fronius Smart Meter 50kA-3
3-phase bidirectional energy meter. Installed at the grid connection point (main panel). Measures grid import/export. Required for accurate self-consumption calculation and battery management. Communicates with GEN24 via Fronius proprietary bus.
Fronius Wattpilot 22J
22kW 3-phase EV charger designed for Fronius ecosystem. Automatically adjusts charging current based on real-time PV surplus — no KNX logic needed for basic solar charging. Optional Modbus TCP for KNX integration.
BYD HVS / HVM Battery
High-voltage lithium battery system paired with Fronius GEN24 Plus. 5.1–12.8 kWh (modular). Battery SoC, charge/discharge rate readable via Modbus from the Fronius inverter register map.
Fronius FAQ
How do I read Fronius solar data into KNX?
Two paths: (1) Modbus TCP — Fronius GEN24 supports Modbus TCP on port 502. A KNX-Modbus gateway reads PV power (register 499), grid power (register 502), battery SoC (register 1), etc. KNX group addresses carry these values to ETS logic. (2) Home Assistant — HA Fronius integration reads Solar.web API every 10 seconds; HA KNX integration publishes values to KNX group addresses. Option 2 is easier to set up and configure.
Can KNX activate loads when solar is generating?
Yes — this is the core self-consumption use case: Fronius PV surplus (W) → KNX group address via Modbus/HA → KNX logic: if surplus > 2000W → close EV charger relay (via KNX actuator, Easee start-charge API). If surplus > 3000W → start pool pump. If surplus > 4000W → activate second EV charger. When PV drops → reverse. KNX logic module (MDT Logikmodul or HA automation) handles the thresholds.
Does Fronius Wattpilot work with KNX?
Fronius Wattpilot has built-in solar self-consumption logic — it reads PV surplus directly from the Fronius Smart Meter without any KNX involvement. For KNX integration, use Wattpilot's Modbus TCP interface (same as the inverter) to read charging state and control charging current from KNX. But for basic solar EV charging, Wattpilot works autonomously.
Is Fronius Modbus TCP available on all GEN24 models?
Yes — Modbus TCP is standard on all Fronius GEN24 and SnapInverter series. The Fronius Modbus register map is published in the Fronius Solar.web portal. Enable Modbus in the inverter web interface (Solar.web → Settings → Communication → Modbus) and set the IP address. The KNX gateway then reads register 499 onwards.
Need a panel with Fronius components?
We select, procure, assemble and certify. Free initial consultation.
Request consultation →