Principal Solar Institute

A community for development and installation professionals in the solar industry

The Principal Solar Institute Module Ratings

The Principal Solar Institute’s scientifically designed and certified combination of tests and performance standards provide an unbiased, comprehensive rating system – the PSI PV module rating. Seven essential characteristics related to initial and long-term PV module performance are combined to create the PSI Rating:

  • Actual Tested Maximum Power vs. Advertised
  • Temperature Coefficient at Maximum Power
  • Power at Low Irradiance to Power at High Irradiance Ratio
  • Normal Operating Cell Temperature (NOCT)
  • Total Area Efficiency
  • Negative Power Tolerance
  • Annual Power Reduction

These ratings allow you to make comparisons when analyzing PV modules and help you select the optimal PV module.

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PSI Ratings – PV Solar Modules from Xunlight

Here are the PSI Ratings for modules from Xunlight, calculated based on initial performance test data. If you don’t see a solar module that you are considering, contact us and we will try to add it.

Rank Manufacturer Model Type Power
(W DC)
PSI Rating Percentile
1XunlightXRS18-158Thin Film1584.03*1
2XunlightXRU10-74Thin Film743.89*1
3XunlightXR36-315Thin Film3153.86*1
4XunlightXRS18-150Thin Film1503.84*1
5XunlightXRS18-146Thin Film1463.73*1
6XunlightXRU10-71Thin Film713.70*1
7XunlightXR36-300Thin Film3003.68*1
8XunlightXR36-291Thin Film2913.57*0
9XunlightXR38-307Thin Film3073.57*0
10XunlightXR12-88Thin Film883.47*0
11XunlightXR 36-264Thin Film2643.13*0

* Modules denoted with an “*” use estimated values for one or more characteristics. Manufacturers can contact us to provide the missing data for these PV modules.

NOTE: PSI Ratings are based on publicly available data, and are subject to change as additional data and proprietary analyses become available for long-term performance.