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Relationship between Lumen Degradation and Ambient Temperature of LED Luminaires.

Accel
Hello Everyone,


I would like to ask how would someone calculate the lumen degradation of a certain LED Luminaire in varying ambient temperatures.

For example, this luminaire from TRILUX -------->https://www.trilux.com/products/en/7650B-LED4000-840-ET-05/

It has a mean rated service life L85 (50 deg C) = 50 000 hrs

How would I calculate in order to get the L value at e.g. t = 25 deg C?

TRILUX has their own Lifetime Calculator and it gave an L value of 94.

How did they arrive with that value? Does it have a formula or only a rule of thumb?


Thanks,
Parents
  • 0
    Realise that a large no. of so called LED failures are actually a failure of the cheaply made driver electronics, though in the case of a stripe of LEDs going, I suspect one open circuit in  series parallel network, so one series stripe has gone dark. It may now be that those remaining are being a bit over-driven.


    However, all semiconductors, LEDS or cheap power supplies, benefit greatly from cool running.

    When over-voltages have been correctly suppressed (and that is another can of worms) then the life is limited by thermal factors, that for silicon can halve the lifespan for an 8 degree increase at the top end.

    Electronics designed for places like down oil wells may run well above soldering temperatures (being brazed) and can have very short lifespan indeed (less than thousand hours )
    app note about it.



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  • 0
    Realise that a large no. of so called LED failures are actually a failure of the cheaply made driver electronics, though in the case of a stripe of LEDs going, I suspect one open circuit in  series parallel network, so one series stripe has gone dark. It may now be that those remaining are being a bit over-driven.


    However, all semiconductors, LEDS or cheap power supplies, benefit greatly from cool running.

    When over-voltages have been correctly suppressed (and that is another can of worms) then the life is limited by thermal factors, that for silicon can halve the lifespan for an 8 degree increase at the top end.

    Electronics designed for places like down oil wells may run well above soldering temperatures (being brazed) and can have very short lifespan indeed (less than thousand hours )
    app note about it.



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