SMA Sunny Tripower X 15 kW Three-Phase Inverter 3 MPPT
15 kW three-phase string inverter SMA Sunny Tripower X, 3 independent MPPTs, PV generator up to 22,5 kWp and integrated System Manager for 5 inverters and one energy meter.
Maximum efficiency 98,2% (European 97,8%), IP65 with C5 corrosion category, DC disconnector and SMA ArcFix arc protection. Size above 11,08 kW: to be paired with an interface panel with SPI and test report.
The SMA Sunny Tripower X 15 (STP 15-50) inverter is a 15 kW three-phase string photovoltaic inverter with 3 independent MPPTs, photovoltaic generator up to 22,5 kWp and integrated System Manager. It is the most widely used size in self-consumption systems for workshops, farms and hospitality facilities, where daytime consumption is high and grid feed-in must be kept under control.
Why 15 kW is cost-effective for business self-consumption
In a three-phase supply with consumption concentrated in the middle of the day, 15 kW of AC power covers a large part of the base load without oversizing the connection. The 22,5 kWp allowed on the DC side enables 50% oversizing: the production curve widens towards morning and evening, exactly when consumption occurs, and peak hours are limited only a few days a year. With an SMA Energy Meter or a Sunny Home Manager 2.0, SMA Dynamic Power Control dynamic regulation is activated, down to zero feed-in where required by the grid operator.
STP 15-50 technical specifications
| Nominal AC power (230 V, 50 Hz) | 15.000 W |
| Nominal / maximum apparent power | 15.000 VA / 15.000 VA |
| Maximum PV generator power | 22.500 Wp STC (DC/AC ratio 1,5) |
| Maximum input voltage | 1.000 V |
| MPPT range / nominal voltage | 260-800 V / 580 V |
| Minimum / start-up voltage | 150 V / 188 V |
| Independent MPPTs / strings per MPPT | 3 / 2 |
| Usable current per MPPT / short-circuit current | 24 A / 37,5 A |
| Nominal / maximum output current | 21,7 A / 25 A |
| AC connection | Three-phase 3-(N)-PE, 220/380 - 230/400 - 240/415 V |
| Maximum / European efficiency | 98,2% / 97,8% |
| Standard protections | DC disconnector, grid and ground fault monitoring, DC reverse polarity protection, all-current-sensitive RCMU, SMA ArcFix AFCI |
| Protection rating / corrosion | IP65, C5 category (IEC 61701) |
| Operating temperature | -25 °C / +60 °C |
| Noise level / night-time consumption | 59 dB(A) max / under 5 W |
| Connections | DC SUNCLIX, spring-cage AC, Ethernet (2 ports), WLAN, Modbus SMA and SunSpec, Speedwire |
| Dimensions (W x H x D) / weight | 728 x 762 x 266 mm / 35 kg |
| Warranty | 5 years, extendable to 10, 15 or 20 years |
| Certifications | CEI 0-21 and CEI 0-16, EN 50549-1/-2, IEC 62109-1/-2, CE |
Regulatory obligations above 11,08 kW
With 15 kW, the system is clearly above the 11,08 kW threshold of CEI 0-21: the interface protection built into the inverter is no longer sufficient. An interface panel is required, with calibrated SPI relay, interface device (DDI) and test report to be submitted to the distributor together with the declaration of conformity and the single-line diagram. This is a cost that must be planned at the quotation stage, not after the system has been installed: choosing the correct size avoids having to redo the panel when the system is expanded.
String sizing
The MPPT range starts at 260 V: compared to the 12 kW model, slightly longer strings are needed to start tracking even under cloudy skies. As a guide, with modules of around 34 V Vmp, the reasonable minimum string is 9-10 modules and the maximum is around 20, to remain within 1.000 V with winter temperatures.
Each MPPT accepts two strings, but the usable current is 24 A: with 14-15 A TOPCon modules, two parallel strings exceed the limit and the inverter clips the peaks. It is better to balance the strings across the three trackers.
What is needed to complete the system
- Interface panel with SPI, DDI and test report
- DC field panel with disconnectors, fuses and 1.000 V surge arresters for industrial rooftop arrays
- Type 2 or type 1+2 DC surge arresters that can be integrated into the inverter (optional SMA kits)
- SMA Energy Meter or Sunny Home Manager 2.0 for self-consumption and zero feed-in
- Roof or ground mounting kit for non-wall-mounted installations
Frequently asked questions
How many kWp of panels can I connect to the STP 15-50?
Up to 22.500 Wp, i.e. around 45-50 modules of 450-500 W on 3 MPPTs with a maximum of 2 strings each. The DC/AC ratio of 1,5 is declared by SMA and does not invalidate the warranty.
Is the interface panel required even if the inverter is CEI 0-21 certified?
Yes. The certification concerns the inverter’s behaviour towards the grid, while above 11,08 kW the standard requires an external interface protection system with a dedicated device and test report. These are two separate requirements and both are needed.
Can I install two Sunny Tripower X units on the same system?
Yes. The System Manager function of one of the inverters manages up to 5 SMA inverters and one energy meter, for a total of 135 kVA, without adding a datalogger. Above that limit, an SMA Data Manager is used.
How much does a 20 kWp system with this inverter produce in one year?
In Central Italy, a well-exposed 20 kWp array produces on average 26.000-28.000 kWh per year, around 1.300-1.400 kWh per kWp. Actual production depends on latitude, inclination, shading and module soiling.
Is it suitable for installation near the sea?
Yes: the enclosure is IP65 with C5 corrosion category according to IEC 61701, the strictest, and the temperature range is from -25 to +60 °C. It is still advisable to avoid direct exposure to the sun during the middle of the day to reduce thermal derating.
