Fronius Symo 3.7-3-S Light Three-Phase Inverter

Product Description

The Fronius Symo 3.7-3-S Light Three-Phase Inverter prioritizes simplicity: a single high-performance MPPT for homogeneous roofs, European efficiency of 96.7%, and the same SnapINverter IP65 chassis as the Symo family. By not including WLAN/Ethernet or a web server, it integrates directly with meters or EMS via RS-485, reducing costs without sacrificing reliability or electrical safety.

Main Features

• Nominal power: 3.7 kW three-phase; European efficiency ~96.7% (max η 98%).
• 1 MPPT with DC range 150–1000 V; Umpp 150–800 V; startup 200 V.
• DC inputs: 3 on the single MPPT (16 A usable; max Isc 31 A).
• Integrated safety: DC isolator, insulation monitoring, and polarity protection.
• IP65, active ventilation, and front access to terminals for quick installation.
• Light connectivity: RS-485 Modbus RTU (SunSpec) and digital I/O.

Advantages or Benefits

• Very simple and economical electrical design for single-orientation roofs.
• Lower CAPEX and OPEX thanks to SnapINverter and direct integration with the EMS.
• Reliable outdoor operation with active thermal management and IP65 rating.
• Compatibility with grid functions (power limitation, programmable cos φ).

Purpose or Applications

Three-phase residential self-consumption, small warehouses or carports with a single orientation; projects with zero feed-in and centralized monitoring without the need for TCP/IP communications in the inverter.

Technical Specifications

Compatibilities

RS-485 (Modbus RTU) for integration with Fronius Smart Meter and EMS; compatible with Wattpilot (surplus to EV) and Ohmpilot (DHW). Prepared for SPD on the inverter's own DIN rail.

Fronius Symo 3.7-3-S Light offers the simplest and most robust way to achieve reliable three-phase self-consumption when the entire roof shares the same orientation.