Life expectancy of high brighness flashlight bulbs (e.g. SureFire M6) and LEDs

I'd like to know the life expectancy of the bulbs used in high brighness flashlights like the SureFire Guardian M6 (also known as MN21) with 500 lumen.
I remember having read somewhere that there are lights which are very bright but with a bulb which has to be changed after a few hours of use (which sounds rediculous to me).
Thanks!

By the way:
Does someone happen to know the life expectancy of the LED in the SureFire U2 (Digital Ultra)?

Ice,

The overall output tells you nothing about the life of a lamp. I have a 65W 1600 lumen Osram lamp with a FOUR THOUSAND HOUR life. What you need to know is the CCT (correlated color temperature). This is the "brightness" or "whiteness" of the beam.

The SF MN20 and MN21 lamps both have 35 hour life spans.

LED life expectancy depends on how hard you drive it, but I suspect that even if you use your U2 on high all the time, it will be good for many thousands of hours, but perhaps someone who knows for sure can chime in here.

Lumileds rate the Luxeon V at 500 hours *to half brightness* at a drive level of 700ma. That is to say, it will still be putting out light, just half the amount of when it was new.

kakster said:

Lumileds rate the Luxeon V at 500 hours *to half brightness* at a drive level of 700ma. That is to say, it will still be putting out light, just half the amount of when it was new.

Click to expand...

Hmm...and the highest light level is consuming about 1500ma!

One big difference is shock resistance.... drop an incandescent while it's putting out lumens and it could be game over instantly if the light hits a sold surface head or tail down. The hot, soft wire is subject to a lot of G-force in that situation.

Thanks a lot for the info about the 35 hour life spans of the M6!

Concerning the U2 (LED flashlight): If that LED is estimated at 500 hours at 700mA, then it should work only a fraction of that at 1500mA, shouldn't it?
And since I allready consider it useless if its output falls below about 75% (3/4), that should give me a live expectancy of a few dozend hours!!!
Only 50 hours life expectancy, that's awfully short!!!!!!!!!!!!!! Can that be true?!?

The light may be consuming 1500mA from the batteries, but it's using a boost converter, so less current is going to the LED.

Lumileds provides 3 different pieces of information about white Luxeon V longevity in the datasheet:


Given that Surefire typically provides very good heatsinking, I'll bet you can expect 85%-90% output at 500 hours with the U2. That, of course, is assuming that it's running on high the entire time. If running at reduced output, lifetime will be significantly extended.

Here's a simple explanation of why the white Luxeon V is "different:" http://www.dansdata.com/da5w.htm

Basically, it is an array of four LEDs and it is impossible to keep the phosphors in the top two cool enough to prevent those from degrading relatively quickly. Other Luxeons don't have this problem, and the author refers to it as the "black sheep of the Luxeon family." Single die LEDs have the additional benefit of being more easily tightly focused, as well.

I actually prefer the floody beams the Lux V produces, but I do NOT like its short lifespan.

Some one can make fortune soon converting Lux V powered lights to K2 soon.

U bin LuxIII's output just as much or more and they too will be obsolete in 6 months. K2 will rule all. For only $15 each too.

He feel free to run those SureFires they have a lifetime warranty.
I use my L4 a lot and it gets smokin hot in 5 minites.

500 hours is still a while- should be a few years before worry here.