Posted by Tim Jackson on May 18, 2009, 5:37 am
residualselfimage1999@gmail.com wrote:
>
> Given that LED lumen levels can drop if the LEDs overheat
> - LED lumen output charts would be nice too.
LED lumen output also drops with time. LED's don't die, they just fade
away. So lifetime has to be specified in terms of percentage of
original output.
Tim Jackson
Posted by Eeyore on May 18, 2009, 12:44 pm
Tim Jackson wrote:
> residualselfimage1999@gmail.com wrote:
> >
> > Given that LED lumen levels can drop if the LEDs overheat
> > - LED lumen output charts would be nice too.
> LED lumen output also drops with time. LED's don't die, they just fade
> away.
You should see some OSRAM figures I found the other day. Operation at say
1A - life = 50,000 hours. At 1.5A life = 20,000 hrs. At 1.8A life = 200
hrs !
> So lifetime has to be specified in terms of percentage of
> original output.
Same with CFLs and to a much lesser degree even incandescents. The
industry standard way of dealing with this would be to rate output at 50%
lifetime.
Graham
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> Given that LED lumen levels can drop if the LEDs overheat
> - LED lumen output charts would be nice too.