X3 FORTH 125K
The Solax X3 Forth 125K is a three-phase photovoltaic inverter with 125 kW and 12 independent MPPTs for large-scale commercial and industrial systems. Maximum DC voltage 1100 V, IP66 protection, integrated zero feed-in, 24/7 cloud monitoring. The most powerful model in the X3 Forth range with standard voltage.
The Solax X3 Forth 125K is the three-phase photovoltaic inverter with 125 kW of power, at the top of the X3 Forth range in standard voltage versions (non-MV). With 12 independent MPPTs and 2 string inputs per tracker, it represents the most complete solution for large-scale commercial and industrial systems that require maximum flexibility in generator field configuration, without resorting to medium voltage (MV) versions.
Why choose the Solax X3 Forth 125K?
The 125K model is almost identical to the 120K in terms of structure and connections, but offers 5 kW more nominal power — a significant advantage for systems that must comply with specific thresholds imposed by GSE connection procedures or POD contractual limits. Thanks to 150% oversizing, the PV generator can reach up to 187.5 kWp, maximizing annual production and return on investment. The 12 MPPTs with 24 string inputs make it perfect for installations on multi-pitched roofs, agrivoltaic structures, or ground-mounted parks with variable topography.
Solax X3 Forth 125K Technical Specifications
| Nominal AC Power | 125 kW |
| Number of MPPTs | 12 |
| Strings per MPPT | 2 |
| Maximum DC Voltage | 1100 V |
| MPPT Voltage Range | 180–1000 V DC |
| Max Short-circuit Current per MPPT | 46 A |
| PV Input Oversizing | 150% |
| Maximum Efficiency | 99.9% |
| Protection Rating | IP66 |
| SPD Protection | Type II (DC and AC) |
| AFCI Protection | Optional |
| Cooling | High-efficiency intelligent ventilation |
| Fuse Design | Fuseless, integrated string current monitoring |
| Dimensions | 985 × 660 × 327.5 mm |
| Weight | 87 kg |
| Warranty | 5 years (6 years with active cloud) |
Cloud Monitoring and Predictive Maintenance
The Solax X3 Forth 125K connects to the Solax cloud platform via datalogger (Pocket LAN or Pocket Wi-Fi+LAN) for real-time monitoring of production, MPPT status, and alarms. The intelligent I-V curve diagnosis automatically detects degraded or abnormal strings without the need for manual measurements. Firmware updates and modification of all operating parameters are available remotely. For multi-inverter systems, the Solax DataHub1000 centrally manages all units with aggregated export power control.
Export Control and CEI 0-16 / CEI 0-21 Compliance
Like the entire X3 Forth series, the 125K model integrates export power control to the grid (zero feed-in function), essential for systems connected to the public grid subject to distributor constraints. Nighttime reactive power compensation and reactive power management meet the regulatory requirements of CEI 0-16 (medium voltage) and CEI 0-21 (low voltage). The PLC system is available as an option for advanced communications with the grid operator.
What is included in the supply?
- Solax X3 Forth 125K inverter
- Integrated SPD Type II protection (DC and AC)
- Optional AC connector for aluminum cable
- Complete technical documentation and official Solax datasheet
Frequently Asked Questions
What is the difference between the Solax X3 Forth 120K and X3 Forth 125K?
The two models have the same mechanical structure (identical dimensions and weight at 87 kg) and the same number of MPPTs (12). The difference is in the nominal output power: 120 kW for the 120K and 125 kW for the 125K. The 125K model may be preferred when the connection procedure or supply contract requires installed power thresholds above 120 kW, or when the project requires a wider operating margin.
How many kWp of panels can be installed on the X3 Forth 125K?
With 150% oversizing, it is possible to connect up to 187.5 kWp of photovoltaic generator. This design strategy is common in Italian commercial systems because it maximizes full-power operating hours on partially cloudy days, significantly improving annual energy yield compared to a 1:1 panel-to-inverter ratio.
Is the Solax X3 Forth 125K suitable for agrivoltaic systems?
Yes, thanks to its 12 independent MPPTs, the X3 Forth 125K efficiently manages systems with strings of different lengths or with variations in tilt and orientation typical of agrivoltaic structures. The IP66 protection ensures reliability in open environments exposed to rain, dust, and temperature fluctuations. 24/7 cloud monitoring allows performance checks remotely without on-site intervention.
Does the X3 Forth 125K support medium voltage (MV) connection?
The 125K model is the standard voltage version (LV/MV via external transformer). Solax also offers the X3 Forth 136K-MV and 150K-MV versions with integrated medium voltage output. For systems requiring direct MV connection without a dedicated external transformer, those versions are more suitable. For systems connected via MV substation with transformer, the 125K is the correct solution.
How is the zero feed-in function configured on the X3 Forth 125K?
The zero feed-in function is configured via the inverter display or remotely via the Solax cloud. It is necessary to connect a bidirectional measurement meter at the point of connection to the grid (POD), which communicates with the inverter to modulate the injected power in real time. The system reacts in milliseconds to keep the export at zero or at the set limit value, in compliance with the requirements of the local distributor.
