STP125-70

The SMA Sunny Tripower STP125-70 is the three-phase string inverter with 125 kW power designed by SMA Solar Technology for commercial and industrial (C&I) photovoltaic systems in decentralized settings, up to the megawatt range. With 12 independent MPP trackers and 24 DC inputs, it allows for extremely flexible design on complex roofs, industrial warehouses, ground-mounted systems, and canopy structures.

12 Independent MPPTs — Maximum Design Flexibility

The 12 independent MPP trackers (2 DC inputs each, for a total of 24 inputs) allow you to connect strings with different orientations, inclinations, and lengths without compromising the performance of the entire system. Each MPPT independently manages its own voltage window, optimizing the production of each sub-array individually. This results in:

• Maximum freedom in string layout design
• Reduction of losses from partial shading, also thanks to SMA ShadeFix
• Compatibility with modules of different power ratings and formats within the same system
• Maximum DC input voltage: 1100 V
• Maximum DC power: 187,500 Wp STC (oversizing up to 150%)

SMA ArcFix — Integrated Arc Fault Protection

SMA ArcFix (AFCI — Arc Fault Circuit Interrupter) is integrated directly into the inverter and continuously monitors the DC strings for characteristic signals of serial and parallel arc faults. If detected, the system automatically interrupts the DC circuit and generates an alarm on Sunny Portal. This function — mandatory in many international markets — significantly increases fire safety for installations, especially on commercial and industrial roofs.

SMA ShadeFix — Software-Based Shading Optimization

SMA ShadeFix is SMA’s proprietary algorithm for advanced management of partial shading. Instead of using additional hardware (optimizers or microinverters), ShadeFix analyzes the I-V curve of each MPPT and identifies the global optimal operating point, even in the presence of multiple local maxima on the power curve. It ensures up to 3% more energy compared to traditional MPPT tracking under non-uniform shading conditions.

SMA Smart Connected — Proactive Monitoring

With SMA Smart Connected, the inverter automatically transmits its diagnostic data to the SMA cloud service. In case of an anomaly or imminent failure, SMA proactively notifies the plant operator and — if under warranty — automatically initiates the component replacement procedure. This reduces downtime and minimizes the costs of unscheduled maintenance.

Communication and Integration in SMA Commercial Energy Solution

The STP125-70 is the central component of the SMA Commercial Solar Solution and natively integrates with:

• SMA Data Manager M (EDMM-20) — management and monitoring of up to 50 inverters (up to 7.5 MW in ring topology) via Modbus, with TPM chip for cybersecurity compliance with European regulations
• SMA Commercial Storage System — integration of the SMA commercial storage system via Speedwire
• SMA EV Charging Infrastructure — integrated energy management for the charging park
• Sunny Portal powered by ennexOS — remote monitoring, reporting, and management via browser without dedicated software
• Protocols: SMA Speedwire, SunSpec Modbus, Modbus TCP

Construction and Installation

The active OptiCool cooling ensures stable operation even at high ambient temperatures, extending the inverter’s operational life. The IP65 protection rating makes it suitable for both indoor and outdoor installation. Commissioning is done via browser (integrated web server) or via the SMA 360° app, with no need for a laptop with installed software.

Full Technical Specifications

• Model: STP125-70 (P/N: 3-125-1100-1-70)
• Manufacturer: SMA Solar Technology AG
• Nominal AC power: 125 kW / 125 kVA
• AC connection: three-phase 3-N-PE, 230/400 V, 50 Hz
• Max AC current: 181.1 A
• Number of MPPTs: 12 independent
• Total DC inputs: 24 (2 per MPPT)
• Max DC voltage: 1100 V
• Nominal DC voltage: 600 V
• Max DC current per MPPT: 30 A
• Max short-circuit current per MPPT: 40 A
• Max DC power: 187,500 Wp STC
• DC architecture: fuse-less, Sunclix connector
• DC switch: integrated
• Surge protection: DC Type I+II / AC Type II (integrated)
• Arc fault detection: Integrated AFCI (SMA ArcFix)
• Cooling: active (OptiCool)
• Protection rating: IP65
• Communication: 2x Ethernet LAN, WLAN, Modbus, Speedwire
• AC connection: copper or aluminum
• Commissioning: browser (integrated web server) / SMA 360° App
• Weight: 96 kg
• Dimensions (W×D×H): 795 × 360 × 1020 mm