Lumen Degradation of LEDs in Solar Lighting Systems

The rated life of LED lamps is different from actual life of LED. We can determine the LED light output characteristics over period from lumen maintenance test. LED suffers from thermal expansion and shrinkage which increases the temperature of chip, hotter chip will form dislocation faster and hence fade quickly. Recently low cost lumen degradation test method has been published in IEC 62257-9-5, 2013. The purpose of this study is to analyze the variation in various lighting parameters like luminous flux, color temperature and color rendering index. This experiment was carried out on LED lighting systems by keeping them switched ON for 2000hrs at STC conditions. It has been observed that degradation level of lumen in different lights reduced to 5-30% however no significant change observed in color temperature and color rendering index.