5W Luxeon lifespan

Beretta1526

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I've heard that the 5W Luxeon has a 1000 hour (not a mistake, 1k hrs.) mean operational time in most applications. This is significantly less than the 1W Luxeons. Can anyone confirm this? /ubbthreads/images/graemlins/popcorn.gif

/ubbthreads/images/graemlins/sssh.gif, but I also hear that a 2 or 3 (my guess is 2½) Watt Luxeon is close. /ubbthreads/images/graemlins/sssh.gif
 

PsycoBob[Q2]

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That's only for WHITE 5w's. The lifespan is heavily dependent on temperature, as noted in Lumileds ds40.pdf (for the Star V Portable, as they call it).

Colored 5w have the usual 100k hour lifespan. You can login to the lumileds site by clicking the 'guest' button, and grab all the datasheets you want. /ubbthreads/images/graemlins/smile.gif Dunno when they added that button- a few months ago, you had to register and login...
 

FlashlightOCD

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1,000 Hours is a lot.

Using the SF L4 as an example:

If you used a set of batteries every day of the year it would still last over two years. You would also have spent 10x more on batteries than you did on the light.

I suspect by the time the 1,000 hours is up, you will have smaller, brighter, and better lights available.
 

Beretta1526

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It is a lot, but minute compared to the 1W...

With that said, one of my vendors has switched out an array of 70 5mm blue LED's in a light engine for 5 1W blue Luxeons in a circular array. They found that the luxeons are much more reliable than the 5mm LED's. They have the same life expectancy, but much higher failure rate.
 

Ben H

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Anyone know what the output degredation over time is for the the 5W run at some specified conditions?
 

Klaus

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[ QUOTE ]
FlashlightOCD said:
1,000 Hours is a lot.
Using the SF L4 as an example:


[/ QUOTE ]

Depends on what you do - using rechargeables and a daily "dose" of 3 hours usage it´ll probably fail under 1 year and your battery cost will be pretty close to 0.

Klaus
 

FlashlightOCD

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[ QUOTE ]
Klaus said
Depends on what you do - using rechargeables and a daily "dose" of 3 hours usage it´ll probably fail under 1 year and your battery cost will be pretty close to 0.

Klaus


[/ QUOTE ]

True, ignoring the cost of the charger, rechargable batteries, and electricty to charge the batteries ... just joking :)

I'm not trying to be a smart a$$ here, but I am genuinely curious as to what kind of job requires three hours of flashlight use every day?
 

leddite

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aren't 5W luxeons being used in some car applications, like for marker lights and such? if you commute for 1-2 hours a day, 50 weeks a year, 5 days a week, 2 hours a day: 500

i guess they figure the warranty will expire and/or they'll be cheaper by then?
 

PsycoBob[Q2]

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Only WHITE 5w LS's have this little problem, not the colored ones.

According to the Lumiled's 5w 'Portable' datasheet, it's temperature dependant. Datasheet. Just click the 'Login' button next to the Guest section, and it'll let you download it. The 'Lumen Maintenance' item is on the bottom of page 8.
 

markus_i

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Not necessarily flashlights - but imagine the white 5 watters as bicycle lights. Depending on your riding/commuting habits, 500 hours can be done in one or two years without problems (I'm cycling to work with a round trip time of roughly one hour a day every day, my SO has a round trip time of two hours, but only cycles during the 'good' part of the year. Nevertheless, each of us would reach those 500 hours in two years).
If it wasn't for the lifetime, the 5W with the elliptic reflector/collimator could make a very nice bike light, directly driven from the generator (which usually can be considered as a 500 mA cc source). As it is, ordinary halogen bike lights (e.g. Cateye 1600 or b&m Lumotech) give more bang for the buck /ubbthreads/images/graemlins/icon23.gif.
If the Lumiled was easily replaceable (like a bulb), it might be a different story, even at their current price.

Bye
Markus
 

Klaus

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Markus,

this is why maybe the **bad** current ones are named "portable" and not "mobile" /ubbthreads/images/graemlins/grin.gif

Klaus
 

Ben H

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From the Luxeon Datasheet, it appears that if the LED is driven at 700mA with a heatsink temp of 167 deg F after 500 hrs of operation the lumen output will be reduced by 25%. "Average lumen maintenance is dependent on heatsink temperature." according to the datasheet. Am I reading this correctly?
 

Jonathan

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I've not re-read the datasheet recently, but Luxeon specifies a maximum junction temperature, a thermal resistance from junction to heat sink, and an operating power. From these you can work back to a maximum heat sink temperature. For the 1 W Luxeons, I believe that the maximum junction temperature is _125C_. For the 5W Luxeons, I think they use _135C_. Working back to the heat sink temperature, and you get _damn hot_ /ubbthreads/images/graemlins/smile.gif

The problem is that these temperatures are too high for the phosphors, and the output degrades much more rapidly than is expected for LEDs. With good heat sinking, you can get operation at much lower temperatures, and presumably get much better life from the devices.

-Jon
 
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