The Sungrow SG15/17/20RT series are three-phase grid-tie inverters designed for reliable operation in larger installations - from complex domestic systems to commercial and light industrial setups. Their key advantage is the 2x MPPT, which simplifies the design of rooftop systems with different orientations or partial shading - each tracker independently optimizes the strings' performance, improving daily energy yield.
These inverters offer high European efficiency, meaning truly good energy conversion under typical operating conditions in Poland - translating to lower losses and more predictable production. They feature extensive communication and monitoring: WLAN and Ethernet, along with remote viewing via an app, facilitating service and quick diagnostics.
These are not hybrid models, so they do not directly work with energy storage systems unlike battery inverters. In practice, they are chosen where reliable grid export, safety features, certifications, and standard, long-term warranty are important.
Ranking
Specifications
Pros and cons
Sungrow ranked first in the BloombergNEF Inverter Bankability Survey 2025 with 100% of surveyed financial institutions casting a positive vote - for the sixth year in a row. For project developers and investors, this translates into easier access to project financing and a well-founded confidence in the enforceability of the manufacturer's long-term warranty (10 years standard, with extension options available).
The inverter operates across the full 0-100% power range using natural convection only - a large rear heatsink with no fans - eliminating all moving parts and mechanical noise. The standard IP65 rating allows outdoor installation without any additional enclosure. Both features directly reduce service costs and increase MTBF compared to forced-air-cooled models.
The unit includes an integrated Arc Fault Circuit Interrupter (AFCI), DC disconnect switch, Type II SPD surge protection on both AC and DC sides, and active PID recovery - the full set required under Polish grid connection conditions and the PN-EN 62109 standard. In this power class, several competing models (e.g., the older Fronius Symo) offer AFCI only as a paid option.
A startup voltage of 160 V and an operating range up to 1000 V across two independent MPPTs allow flexible string design even under winter low-irradiance conditions or with bifacial modules. At 15-20 kW output, the inverter weighs just 18 kg, enabling single-person installation and avoiding excessive load on lightweight rooftop mounting structures.
A maximum efficiency of 98.5% places this series on par with comparable SMA STP and Huawei SUN2000 models in the same power class. The integrated WLAN module and Ethernet port, combined with the iSolarCloud platform, support remote diagnostics and over-the-air firmware updates without requiring an on-site service visit.
The SG15/17/20RT-P2 series (datasheet V2, 2023) is Sungrow's current mainstream offering in this power segment and provides, among other improvements, a higher DC oversizing ratio. The original RT series is being progressively phased out by European distributors, which may result in reduced stock availability and a shorter after-sales support horizon for new installations.
Alternatives
About the SG15/17/20RT series
These answers cover the whole series. Where a figure differs, the specification above is this model's own.