• Elmvang, Stig
• Corell, Dennis Dan
• Olsen, Lau
• Dam-Hansen, Carsten
• Frimodt, Henrik
• Thorseth, Anders

Abstract

LED lighting products don’t always meet their rated lifetime and may fail prematurely, reducing the expected energy savings in installations. The project aimed at obtaining new knowledge about the lifetime of LED products, using the new EU endurance test introduced in 2021. The on/off power cycling introduced should stress the product and catch early failures, compared to established test methods using continuous operation for longer durations. The project has established new laboratory test facilities and procedures for running the lifetime tests and comparing the results of the test methods. A new monitoring system has been developed and tested in the laboratory for continuous logging of temperature and light output of individual lamps. An automatic test system has been developed for the partners to be able to run the EU endurance test on single LED lamps in their own facilities. Multiple samples of different types of LED lamps and retrofit modules have been tested in parallel using the two test methods. The results have been analyzed and compared, showing good correlation for maintenance at 3000 h. The LED lamps and modules tested in the project period all passed the EU endurance test with only a single catastrophic failure. Both tests showed very high luminous flux maintenance factors making it difficult to estimate the actual lifetime by extrapolation, for this longer testing would be needed. The results are of a wide general interest and have been disseminated to the lighting industry and the research community, through trade magazine articles, conferences, international collaboration, and a thematic day on LED lighting technology with laboratory demonstration. The knowledge and facilities will be used in teaching, impartial testing for industry, and in research. Further testing on the LED products, will provide comparison data for research on a new 1500 h lifetime test at elevated temperatures, leading the way for a faster and better lifetime test method.

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