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What Everyone Should Know About Lm80, Led Lifetime


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Everybody always asks for "LM-80 data", but nobody seems to know what it really is. This short primer should be helpful in decrypting this mystery, and focusing everyone on asking the right questions about LED and SSL luminaire lifetime.

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What Everyone Should Know About Lm80, Led Lifetime

  1. 1. What Everyone Should Know about LM80, LED Lifetime<br />April, 2010<br />
  2. 2. IES LM-80 – an LED Testing Standard ONLY<br />“Approved Method for Measuring Lumen Maintenance of LED Light Sources”<br />Specifies procedures for measuring lumen maintenance of LEDs and LED modules (but not luminaires)<br />Note: Lumen Maintenance ≠ LED Lifetime<br />pg. 2<br />
  3. 3. Everyone Asks for an “LM-80 Test Report”<br />Here is what one looks like (too detailed, no interpretation, just data…):<br />DOE has requested controlled dissemination of these reports, available under NDA<br />
  4. 4. LM-80 Test Summaries<br />Usually in graphical form, all LED lamp manufacturers supply these freely (unrestricted by DOE)<br />Much more useful in determining lumen maintenance of a given LED lamp system<br />
  5. 5. L70 Lumen Maintenace≠ LED Lifetime<br />“LM-80 data” does not predict anything<br />Lifetime predictions come from the LED manufacturer and there is no current industry standards for calculating LED lifetime (IES TM-21 is working on this)<br />This is an example Cree’s LED lifetime prediction model output:<br />More info at:<br />
  6. 6. LED Lifetime Is Irrelevant<br />System Lifetime is What Creates Value<br />Heat Sink: Linchpin of the entire system. If this is poorly designed, all the other components can be compromised<br />Driver: Currently the weakest point of the system, but the big companies are working on this<br />LED Lamps: Practically never fail; depreciate very slowly in a well-designed system<br />Optical Components: Can (rarely) yellow over time and lose light; system design choice<br />