Growatt WIT 28-55kW series is a three-phase hybrid inverter designed for commercial and industrial installations, where stable network operation and realistic energy self-consumption with energy storage are key. What sets it apart is the built-in UPS and black start function, enabling selected circuits to remain powered and allowing the system to start up even after a network outage - a solution particularly useful in service facilities, refrigeration units, or farms.
The use of multiple MPPT trackers facilitates designing PV fields on different roof sections and minimizes losses due to partial shading, resulting in more stable energy yields throughout the day. The high European efficiency means fewer conversion losses under typical climatic conditions in Poland, thus delivering more energy to consumers or storage.
Remote monitoring and communication are available (WiFi, Ethernet modules, 4G solutions, app, and platform), simplifying service and operational control. This series works with high-voltage energy storage systems, features comprehensive safety measures (including SPD type II on both DC and AC sides), and comes with certifications required for target markets and region-dependent, purchase-condition-based warranty.
Ranking
Specifications
Pros and cons
The built-in UPS function switches power to selected circuits in under 20 ms (per manufacturer specification), protecting voltage-sensitive loads such as cold-storage units, servers, and production lines from outages. The black-start capability allows the system to restart without grid availability - a rare feature in the C&I inverter segment that sets this series apart from conventional grid-tied inverters.
Maximum conversion efficiency reaches 98%, with a European efficiency of ~97% - figures that place this series in the upper tier of the 28-55 kW hybrid inverter segment. Over a 20-year system lifetime, this translates into meaningfully higher energy yield under Polish climatic conditions, which are characterized by predominantly partial cloud cover and frequent below-rated irradiance levels.
A DC/AC ratio of up to 2.0 allows safe PV array oversizing without clipping risk, boosting morning and afternoon energy harvest. Multiple independent MPPT trackers (input up to 800 V DC) enable strings with different orientations and tilt angles to be handled separately, minimizing partial-shading losses - a key advantage on the complex roofscapes typical of industrial facilities.
The series supports parallel connection of multiple units, delivering a combined AC output of up to 165 kW within a single system. This allows installations to be expanded incrementally as site demand grows, without requiring inverter replacement - a significant advantage for warehouses and commercial facilities with phased build-out plans.
Factory-fitted Type II surge protective devices on both the DC and AC sides eliminate the cost and installation of additional SPD modules otherwise required under IEC 60364-7-712 for commercial PV systems. Continuous operation at 110% of rated AC load ensures stability during motor start-up transients and momentary demand spikes.
Growatt does not appear on the BloombergNEF Tier-1 Power Inverter Manufacturers list (as of Q1 2026 per available publications), which may represent a barrier to project financing by banks and funds that require this classification as a condition of project finance. Competitors such as SMA, Fronius, and Huawei hold Tier-1 status, giving them a structural advantage in institutional tenders and debt financing processes.
The base manufacturer warranty is 5 years - below C&I market expectations, where SMA offers 5 years with an extension option up to 20 years (SMA Extended Warranty) and Fronius provides a standard 5-year warranty extensible to 10 years. For commercial sites operating under bankable long-term agreements such as PPAs of 15+ years, a short base warranty period represents a genuine contractual risk.
Alternatives
About the WIT 28-55kW series
These answers cover the whole series. Where a figure differs, the specification above is this model's own.