Luxeon V - rated life?

[iocheretyanny]

Why are some people saying Luxeon V rated life is lower then other LED's?

Isn't it 100,000 hours?
Maybe it's the Luxeon V Portable Star's that are rated at only 1000 hours?

Which one sdoes Surefire use?

 

[NewBie]

Nope. Good eye!

The lifetime for the Lux V can be very low, depending on drive level and heatsinking. This is one of the major drawbacks of the LumiLEDs Luxeon V.

This is a major stumbling block for the device that many don't realize.

Deep within your flashlight, is a point where the Luxeon V attaches to the heatsink.

If this point reaches 85C, and you only drive it with 600mA, the light output of your flashlight will drop by 35% in only 500 hours.

If this point reaches 75C, and you only drive it with 700mA, the light output of your flashlight will drop by 25% in only 500 hours.

If this point reaches 35C (which is highly unlikely, except in big flashlights that can heatsink the power well), and you only drive it with 700mA, the light output of your flashlight will drop by 10% in only 500 hours.

See page 8 here, http://www.lumileds.com/pdfs/protected/DS40.PDF

 

[jbfla]

NewBie,

Thanks for the link. I'm still learning, too.

I was surprised today when I received a light with a Lux V, and the packaging stated an "LED life" of 1,000 hours. Much less than the 10's or 100's of thousands of hours claimed for other LEDs.

Really doesn't make much difference to me (but nice to know)...most likely never will get close to even 500 hours on the light. /ubbthreads/images/graemlins/smile.gif

JB

 

[idleprocess]

There are numerous reports of LuxVs lasting substantially longer than 500 hours, but the wording in Lumileds' spec sheet makes most folks a bit uneasy.

I have to wonder if after 500 hours some small yet signifigant percantage of LuxVs crash? There have been enough people reporting good operation beyond 500 hours that I wonder if the "problem" effects even 20% of all LuxVs.

Adequate heatsinking is critical regardless.

 

[jonman007]

Does anyone know how long the LED in my SF L2 will last if used primarily on low?

 

[evan9162]

The 500 hour (1000?) only applies to the white Luxeon V. The green/blue Luxeon V LEDs have the traditional 50K hour lifetime.

 

[IsaacHayes]

Evan, what you said is true and that makes me think that the problem is the phosphur, that it degrades with heat.. is this the problem?

 

[evan9162]

That's what it sounds like to me. We know how cool the junction is being held by virtue of slug temperature and thermal resistance from slug to junction. That covers the junction -> slug side. But what we don't know is how hot things are on the other side (the side that faces up), which is where the phosphor is. It's possible that heat is radiated up into the phosphor, 4x as much as with a Luxeon I/III, cooking it alive in short order.

 

[IsaacHayes]

Heh, just hope it doesn't get hot enough to "ignite" heh!!
Makes me wonder what phosphur they are using on the prototype/experimental 10W luxeons...

 

[BentHeadTX]

That is why I use the LuxV in a 2D Mag with thick heat sink... I will have it done with the 8AA to 2D adapters come in. If I am happy with it running at 500mA, that is what I will program the nFlex as max output. Don't want to fry the WX1S any time soon.