How to Test the Service Life of LED Lamps

Testing the service life of LED lamps is a complex process that usually involves multiple steps and standards. Here are some key test methods and standards:

  1. Long-term life test: In order to confirm whether the service life of LED lamps reaches 35,000 hours, a long-term life test is required. According to the regulations of the American ASSIST Alliance, the measured light power or luminous flux is the initial value after 1,000 hours of electrical aging.
  2. Luminous flux maintenance rate test: L defines the lumen percentage compared to the initial lumen. For example, L70 means that the luminous flux has decayed to 70% of the initial luminous flux, L80 means that it has decayed to 80% of the original, and L90 means that it has decayed to 90% of the original. The B value represents the failure data at the L data. B10 means that 10% of the LEDs cannot meet the requirements. L/B is the standard definition of lamp life, such as 50,000h (L90/B10), which means that the time taken for 10% of the product luminous flux output to drop below 90% of the initial value is 50,000 hours. In other words, it means that the LED product is reliable, and 90% of the products still have a light decay of less than 10% after working for 50,000 hours.
  3. Temperature influence test: Junction temperature is an important factor affecting LED light decay. The increase in junction temperature will cause the LED light to decay very quickly. This test method uses different driving currents, selects 5 LED lamps, and conducts accelerated life tests with different currents at an ambient temperature of 25°C to obtain a mathematical model of light output decay.
  4. International standards and methods: The Illuminating Engineering Association of North America and the American National Standards Institute have issued standard documents for the maintenance test method of luminous flux and color of SSL lighting LED packages, arrays, and modules (LM-80) and the prediction of long-term lumen maintenance rate of light sources (TM-21). In addition, a newly revised “recommendation” on LED lamp life testing was recently released, recommending the “L70/B50” method, which measures the time taken when the light output of 50% of the products drops below 70% of the initial value, which is the standard definition of the life of LED lamps.

In summary, the service life test of LED lamps involves many aspects, including long-term life test, luminous flux maintenance test, temperature impact test, etc. Through these tests, the performance and service life of LED lamps can be evaluated more accurately.

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