chasm22 said:
Endeavour said:
They don't list specifications for white parts at 1.4A because that part isn't supposed to be driven at 1.4A. The more you overdrive the LED above its rated currents, the faster the phosphor degrades, and the faster the LED dies. One of the virtues of the LED is it's long lifespan, and by overdriving it you throw that out the window and may as well be using a fancy incandescent that you can count on replacing if you use it often enough. This part is obviously rated at 1.4A because it can withstand those currents without decreases in the lumen maintenance of the diode, the others can't.
These red Luxeon IIIs are still Luxeon IIIs. The new parts aren't available yet, and won't be for a while yet. I think, and I'll let someone else more qualified than I verify this, the reason the red parts produce so much more light at similar current levels to other LEDs is because the color red uses far less energy than any of the others (hence why you don't lose your night vision with red lighting vs. blue, white, green, etc.)
Hey Newbie, you're not challenging this statement?????
In particular, Endeavor stating,"This part is obviously rated at 1.4A because it can withstand those currents without decreases in the lumen maintenance of the diode, the others can't." Huh? Lumileds isn't claiming anything of the sort. LUMILEDS IS DOING THE BIG NO-NO. They are overdriving their LED's. At least if overdriving is meant to describe driving a led at higher currents to achieve higher lumen output
at the expense of a decreased lifespan.
Funny how these forums can be. I see critical eyes seemingly always focused on certain people and or certain projects, but these same eyes seemingly skip over the
details when it comes to things like, well things like these lumileds leds. This thread is a perfect example. This is from Lumileds website:
"Lumileds projects that white, green, cyan, blue, and royal blue Luxeon III products will deliver, on average, 70% lumen maintenance at 50,000 hours of operation at a 700 mA forward current or 50% lumen maintenance at 20,000 hours of operation at a 1000 mA forward current. Lumileds projects that red, redorange, and amber Luxeon III products will deliver, on average 50% lumen maintenance at 20,000 hours of operation at a 1400 mA forward current." That appears to be saying that just the opposite of what Endeavor is claiming. They aren't maintaining their lifespans. They going to crash and burn prematurely. Furthermore, lumileds seems to be very cagey in the specs and test results.
I also thought somebody(Newbie??) might comment about the lack of specs for these led's when they are driven at their maximum specifations for current and junction temperature. How about it? They're letting these statements out about 100k hour lifetimes, when they know that they won't come within 50% of that figure when these things are used
within Lumileds own specs. So how about it? Should we ask them for refunds in advance? How's this sound? Since an amber lux III will only live for 20k hours instead of the ballyhooed 100k, we should ask them to sell them for around lets say $2.50 a pop.
This is a ripoff isn't it? Here's the very first thing they say in their literature; "Features
Highest flux per LED family
in the world
Very long operating life (up to
100k hours)
Did I miss something? Which of the lux III's in this group has a projected 100k hour lifespan?
chasm22