The results show that, the advantages of TOPCon’s low-irradiance performance is fully played in the gloomy days and conditions (100-400W/m2) . The overall yield gain is 7.83% over n-type BC modules in 127 days ( November 2024-March 2025), among when 76 days are cloudy or rainy, representing 60%.
Project Background:
The project is implemented by the well-known third party appraisal agency, China General Certification Center. The Outdoor PV Performance Validation Station is located in Meilan District, Haikou City, HainanProvince, which operates as a distributed photovoltaic field test power station, and crucially, the surrounding buildings do not obstruct the test arrays . The validation station is equipped with a fully automated, high-precision environmental monitoring system that meticulously tracks and records meteorological conditions such as irradiance (GHI、DNI、DHI、GTI), as well as temperature, humidity, wind speed and direction, and rainfall.
This specifically purposed study on low -irradiation performance outdoor comparison started from November 15 2024 to March 21 2025, across 127 days including, 45 cloudy and 31 rainy days. The gloomy days account for 60% with light condition of 100-400W/m2 .
Month Sunny Overcast Rainy
2024.11
2024.12 6 12 2 16 8 3 During the 127-day detection period, there
2025.1
2025.2 19 9 10 9 2 10 were a total of 76 cloudy and rainy days, accounting for
2025.3 5 8 8 60%
Total 51 45 31
Module Information:
For this field test, Two types of modules were selected: 10 N-type TOPCon modules and 10 N-type BC modules . The modules were fix-mounted on the roof and are equipped with high-precision sensors to monitor power generation data in real time. This setup ensures the accuracy and credibility of the test results.
Technology Module Numbers Module type
Jinko TOPCon 10 Bifacial
N-type BC 10 Bifacial
Table 2: Product Information
Conclusions:
It serves as real-world evidence that, attributable to its optimized leakage current path, superior fill factor and enhanced shunt resistant, N-type TOPCon results in an approximate 7.83% increase in energy yield over N-type BC during the rainy season with irradiation below 400w/m2 . It underscores TOPCon’ s superior all-day production, especially .on overcast days.
