Can Cree XP-G's change tint over time?

[Dole]

About a month ago my buddy bought a Dereelight XP-G p60 drop-in and it had nasty green tint so he sent it back and it was replaced with a new one with nice white tint. I was just checking it out now (about a month later) and its nasty green all of a sudden.

Can LED's change their tint over time? What do you all make of this?

 

[KuKu427]

Yup! My XP-E light got green after I left it on high through 3 battery changes. :shakehead
I think the term for it is burn-in.

 

[yellow]

*delete*

 

[Pandorum]

Yup! My XP-E light got green after I left it on high through 3 battery changes. :shakehead
I think the term for it is burn-in.

Can I assume the older XR-E as well can change? :(

 

[FloggedSynapse]

(...)
Can LED's change their tint over time? What do you all make of this?

Yes they change tint over time.

The phosphor/scintillator over the LED degrades over time. The LED itself fades with use.

The hotter/brighter you drive the LED, and hotter it gets, the faster it will degrade. If you run the LED at low power levels (20+ hour runtime) it will degrade very slowly.

 

[Justin Case]

Try doing a web search for "LED white point stability".

 

[^Gurthang]

I seem to recall a recent thread about the SST50/90 and that the Vf drops after "break-in". Wonder if the same thing occurs w/ other emitters along w/ the tint shift?

 

[kramer5150]

Yes, if they are over driven beyond the cooling capacity of the thermal design. I also think the flux BIN can change... at least these have been my observations with 1.4A drive circuits and the XRE.

This is why Surefire designs are a step down from their competition, in terms of Lumen output. Favoring longevity and reliability over Lumen output. This is also a BIG part of the premium $$ that goes into the Malkoff drop ins.

This is why I run my DX-MCE with non-IMR cells. Sure its not as bright, but it runs cooler, and I can just leave it ON and use it as a ~250L (ballpark) task light. Which is still VERY bright IMHO. I have owned this light for over a year and had it measured in two different spheres over that time span and its output has not dropped and its white tint has remained constant. In this setup it draws about 2.5A from the 18650.

The counter-argument could be made that an XPG in a 1.4A setup can easily obtain the samle OTF Lumens. But the XPG will be driven harder and closer to its thermal limit than the MCE... at that ~250L level.

 

[burntoshine]

weird! i wonder, what would more neutral white type tints change to...?

 

[kramer5150]

weird! i wonder, what would more neutral white type tints change to...?

The WC XREs that I have over heated turned more yellow-green tint.

 

[Dole]

Well that stinks. He was using it in a surefire 6P and it was the 3SD version so he was using 18650's. But I'd bet he used it on high for maybe 5-10 minutes tops at a time. Wonder if it was just this one drop-in or do all of the dereelight xp-g's change over time with normal use??? :shrug:

 

[tolkaze]

I got mine to change over a small amount of time... I cleaned the contacts of my quark mini aa with a spray contact cleaner, and after using a li-ion, the tint started to change... currently it is a yellow-green. I pretty much destroyed the light, so now its just a toy. might pull it apart and see how it ticks

 

[McAllan]

That sound like the LED has been overloaded. Electrically and/or thermally.

I have an LED desk lamp with 66 5mm LEDs. Originally there was some pretty cool ones was in it but they didn't live up to the actually quite nice mechanically quality of the lamp (Paulmann Flex). I bought some Osram Parathom LED "bulbs" as they consisted of 48 (if I remember correctly) 5mm very nice neutral warm LEDs - almost like the light from halogen bulbs - and slaughtered them for their LEDs as it was much cheaper than buying 5mm separately and getting some more or less unknown.
That's now over 1 year ago and that lamp as working excellent - used 3-5 hours a day - with the "Osram" LEDs (don't know if they're really Osram or just some Osram bought). Haven't noticed any change in those compared to a stock Parathom I have in my closet which is used seconds only every now and then. Further more they've been subjected to quite some heat. First the factory soldering at Osram then my de-soldering them and then finally soldering them in the Paulmann Flex.

I haven't noticed any change in my flashlights either but they're used nowhere as much as the desk lamp. Even my mostly used LD20 which every now and then are used at turbo for 20-30 minuttes at a time. However I haven't got something to compare that with since all my XR-E Fenixes were different from start because of tint lottery. The Osram LEDs are all very much alike (only very minor differences) and there's a number of LEDs to get an average judgment on.

 

[recDNA]

Yup! My XP-E light got green after I left it on high through 3 battery changes. :shakehead
I think the term for it is burn-in.

What tint should I buy so it will be white after burn in? Lol

 

[jimmy1970]

And people wonder why Henry doesn't ask his Clicky/Twisty lights to crank out 240+ lumens.

 

[fnj]

And people wonder why Henry doesn't ask his Clicky/Twisty lights to crank out 240+ lumens.

Exactly. Ra/HDS and Muyshondt lights will last you a LONG time. These manufacturers have a deep understanding of the issues involved in making a long term dependable light.

 

[Dole]

Exactly. Ra/HDS and Muyshondt lights will last you a LONG time. These manufacturers have a deep understanding of the issues involved in making a long term dependable light.

Yes, but the people who are willing to spend $300 on a flashlight that does 120 lumens are not the type of people that want to buy ONE reliable flashlight and stick with it forever with no worries. I think the market for these lights are for flashaholics strictly.

I'm not knocking them though, the price just is too high for me for the return. I think a Surefire 6P with a Malkoff M60L would be just as reliable.

 

[Dole]

... and boo to Dereelight for the green changing tint... :scowl:

 

[Cadster]

For the past month, I've been using a Dereelight Javelin 3-mode on high for short periods and the tint has been a yellow-green. Today I happened to run it on high for about 45 minutes and it got fairly warm but not too hot to handle. The tint has permanently changed to blue-white.

 

[jimmy1970]

Yes, but the people who are willing to spend $300 on a flashlight that does 120 lumens are not the type of people that want to buy ONE reliable flashlight and stick with it forever with no worries. I think the market for these lights are for flashaholics strictly.

I'm not knocking them though, the price just is too high for me for the return. I think a Surefire 6P with a Malkoff M60L would be just as reliable.

Try around $139 for a Ra Clicky that I have no intention of ever selling. My Ra Clicky is the right size for EDC and is every bit as bright as I require at 140 lumens & the light never gets hot with use. Have a look at the Ra Clicky serial number list - there is not a lot of the early models (early adopters) changing hands.

I too have a 6P with Malkoff, and I agree about the dependability of this combo. It is not a comparable model though to a Ra light with its extra size & no ability to alter the output levels etc, etc, etc. And how much is a Surefire 6P with Malkoff? - not much cheaper than a Ra light.

James....:)