Maximum temperature for power LEDs

Discussion in 'The Projects Forum' started by jaclement, Jul 10, 2014.

  1. jaclement

    Thread Starter Active Member

    Apr 15, 2009
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    I am building a plant light using 24 10 watt white LEDs and 80 5 watt red LEDs. I plan to throttle back my current sinks if the heatsink/frame gets too hot. What do you think the maximum case temperature I can use to have a reasonable lifespan for the LEDs?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    The lifetime versus temperature should be given in the datasheet of the leds.
    The hotter the leds are, the shorter the lifetime.
    Perhaps forced cooling would be an option.(using a fan on the heatsink).

    Bertus
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    For long life I shoot for no more than 60-65 deg C measured on the top of the aluminum pad they are mounted on as close to the plastic housing as possible.. (basically right on the +/- stamping in the led posted below)
    LED Junction temps (usually about 20deg C hotter than the heatsink) should never be more than 85 deg C if you want to get the "rated" 50K hours out of them..

    Thats assuming an led like this http://www.mpja.com/1000-Lumen-10-Watt-Super-Bright-Cool-White-LED-Module/productinfo/31325 OP/
     
  4. RichardO

    Well-Known Member

    May 4, 2013
    1,230
    382
    Also, the LED is less efficient at higher temperatures. Again, consult the data sheet for the LED's you are using.
     
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