Comprehensive technical specifications, single-diode physical parameters, and climate degradation benchmarking.
The First Solar Inc First Solar Inc FS-6425-P-B-2 achieves a verified module conversion efficiency of 16.87%, outputting 425W under Standard Test Conditions (1000 W/m², AM 1.5G, 25°C cell temperature). Featuring half-cut cell geometry with multi-busbar (MBB) interconnects, internal resistive series losses (I²R) are reduced by approximately 75% compared to full-cell designs, substantially mitigating hotspot risks under localized partial shading.
Operating with a power temperature coefficient of -0.23%/°C, this module exhibits robust thermal resilience. During peak summer conditions where rooftop ambient air and roof re-radiation drive cell temperatures to 65°C (a +40°C delta over STC), the module will undergo an estimated thermal derating of -9.2%, maintaining an effective output of 386.1W. Ensuring a minimum 100mm standoff ventilation gap above roof decking is strongly recommended to optimize convective heat dissipation.
With a nominal Open-Circuit Voltage (Voc) of 224.8V and Maximum Power Current (Imp) of 2.4A, system designers must account for cold-climate voltage surges. In regions where winter ambient temperatures plummet to -15°C, the cold-temperature open-circuit voltage rises to approximately 4798.4V per module. In accordance with NEC Article 690.7, strings must be sized to never exceed inverter maximum DC voltage limits: maximum series string size is 3 modules on 1000V DC commercial inverters, or up to 5 modules on 1500V utility-scale systems.