On Jun 12, 2:31 pm, " wrote:
On Jun 12, 1:29 pm, wrote: You realize there is a huge gray market in China for LEDs which are
marginal or test rejects that reputable companies stay away from...
It's the same market dynamics for microprocessors, and for
semiconductors in general. Nothing is really thrown away in the trash,
except absolutely dead parts - if it wiggles, somebody will sell it.
What you're doing is basically doing the 100% burn-in screen on these
lower or downgrade binouts. Also, infant mortality is only a very
small part of the so-called reliability bathtub curve - you've seen
only a few beginning data points and you really don't know where the
"knee" of the plateau of this curve is (the LED manufacturer does -
they know exactly what their failure rate curve is based on an
extended, accelerated life test and they also know exactly what kind
of burn-in duration is required to prove out a sample size whereas you
don't...). It's really you get what you pay for, even in China.

They came with batteries, so you can test them on the spot to
guarantee that it is not DOA (actually, for tourist qunatities, the
sellers will demonstrate them for you). Given the markups for at
least two additional middlemen, plus transportation costs, I am
reasonably comfortable that the ones I saw are of the same quality as
the ones sold at Walgreens, Kragen, and Harbor Freight. By
inspection, it certainly seems so. I would not make a trip to China
just to buy some LED flashlights, but I see no good reason not to buy
some if I am already there. At about US$1 each, I consider them
disposable, not treasured heirlooms.

The primary problem is going to be the quality of construction. Most
of the better "white" LEDs seem to come from Nichia Corporation of
Japan. Even many of the cheapie ones sold in China. As long as the
connection is solid and the reflector is reasonable, the light should
be OK.