Hi Bob,

I cannot help with white LEDs, but I can tell you that I did a test of
some blue LEDs (which are name brand, I think) and they ran for more
than 18000 hours at max rated current, room temp, with no noticeable
dimming.

Sean


On Wed, Jul 15, 2009 at 11:50 AM, Bob Blick<bobblick@ftml.net> wrote:
> I recall some talk about short lifetime of some white LEDs but couldn't
> dig it out of the archive.
>
> Now that it's happened to me, suddenly I'm interested :)
>
> I've got some white T1 LEDs from here:
>
> http://www.led-center.com/led/new/white03.htm part number WL3-W15-2500.
>
> At rated maximum of 30 mA they seem to last about 1000 hours at room
> temperature. At 20 mA they last a little longer.
>
> Then they get dim, about 5% of the new brightness. The color stays about
> the same. So I assume the phosphor is OK, it's the blue LED that has
> weakened.
>
> I've never seen this happen with blue LEDs. Maybe the white phosphor
> pollutes the LED?
>
> I haven't had this problem with "name brand" white LEDs.
>
> Anyone see this happen before?
>
> Cheerful regards,
>
> Bob
>
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