Rebel VS Cree durability..?
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Dont know about physical damage (dropping and so on) but I think I remember reading that the rebel tends to produce a little more heat than CREE. So this may make it more susceptible to thermal damage.
Edit: I think I only have that impression due to the advised limits from Fenix on running Rebel / Cree lights on turbo mode.
In short: I have no idea what I am talking about
Edit: I think I only have that impression due to the advised limits from Fenix on running Rebel / Cree lights on turbo mode.
In short: I have no idea what I am talking about
If you have no idea, why are you presenting information as if you were an authority on the subject?
Given the same light output (XR-E Q4 or Q5 and Rebel-100) The XR-E and Rebel will produce around the same amount of heat when driven at the same current level. In fact, the rebel may produce a touch less heat due to the tendency for them to have a lower Vf.
The rebel is a much smaller package than the XR-E, which means that it's more difficult to get good thermal transfer. The time limits on turbo mode are likely a reflection of the difficulty in getting good thermal transfer from a Rebel.
If you're wondering about reliability data, in this area, the rebel is in fact likely better than the XR-E.
According to Cree, the XR-E has a lifetime of 50,000 hours to 70% initial output, with Tj at or below 80C. (http://www.cree.com/products/pdf/XLamp7090XR-E.pdf, page 9)
No where within their documentation (datasheet or reliability data) do they specify the affects of drive current on lumen maintenance.
However, lumileds gives a much more detailed picture about the lifetime of the Rebel. According to this: http://www.luxeon.com/pdfs/RD07.pdf, the Rebel has a lifespan of 60,000 hours to 70% initial output, with Tj at or below 138C (350mA), or 130C (1A). So the Rebel has better high temperature lifespan, and you can see the effects of higher temperatures and higher drive current on lifespan from the documentation provided.
Given the same light output (XR-E Q4 or Q5 and Rebel-100) The XR-E and Rebel will produce around the same amount of heat when driven at the same current level. In fact, the rebel may produce a touch less heat due to the tendency for them to have a lower Vf.
The rebel is a much smaller package than the XR-E, which means that it's more difficult to get good thermal transfer. The time limits on turbo mode are likely a reflection of the difficulty in getting good thermal transfer from a Rebel.
If you're wondering about reliability data, in this area, the rebel is in fact likely better than the XR-E.
According to Cree, the XR-E has a lifetime of 50,000 hours to 70% initial output, with Tj at or below 80C. (http://www.cree.com/products/pdf/XLamp7090XR-E.pdf, page 9)
No where within their documentation (datasheet or reliability data) do they specify the affects of drive current on lumen maintenance.
However, lumileds gives a much more detailed picture about the lifetime of the Rebel. According to this: http://www.luxeon.com/pdfs/RD07.pdf, the Rebel has a lifespan of 60,000 hours to 70% initial output, with Tj at or below 138C (350mA), or 130C (1A). So the Rebel has better high temperature lifespan, and you can see the effects of higher temperatures and higher drive current on lifespan from the documentation provided.
Oh was I being an authority?
I though my verbiage made it clear that the information I presented was of a speculative nature, formed (and possibly mis-informed) by small pieces of information I have gathered from reading here.
So to make it perfectly clear. I am not an expert on LED durability.
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when the Rebels came out, I instantly hated them.
Because they were in no way superior to Cree and because of this small size that keeps them from being good for the modder.
BUT
much to my surprise, there have not been any problems shown up with them getting loose, die from heat or shock, or whatever.
I thought that this will happen for sure and posted it at that time - and was more than wrong.
They sure are as good and its a dead race comparing these leds.
Because they were in no way superior to Cree and because of this small size that keeps them from being good for the modder.
BUT
much to my surprise, there have not been any problems shown up with them getting loose, die from heat or shock, or whatever.
I thought that this will happen for sure and posted it at that time - and was more than wrong.
They sure are as good and its a dead race comparing these leds.
Oh was I being an authority?
Hey, don't feel bad. That's what comes with the territory when "whuppin' it out to see who has the biggest one" is replaced by "post count".
With the zillion hours life attributed to pretty much any LED, they're all going to be shining still when most of us are in a very dark place a few feet under the ground where no flashlight will save our butt.
Hell, even batteries now want to get into the act. I just bought a pack of Alkalines last weekend with an expiration date of 2021.
That bothered me for a moment and I didn't know why, but I snapped a minute later and realised... that for the first time, the expiration date for the batteries I just bought is probably further out there than my own "expiration date".
Now I think I'll just go sit in the dark and ponder such things while staring into a Q5 emitter and wonder what would happen if I "went into the light".
Bolster
Flashlight Enthusiast
LOL! You funny, Zenster!
BentHeadTX
Flashlight Enthusiast
So to make it perfectly clear. I am not an expert on LED durability.
I am an EXPERT on LED durability... knock the dome off those things and it screws up the white wall hunting beam shots. Break a lead off a Luxeon and output plummets although runtime is increased. Put 5 amps into a Luxeon I and there is no more discussion about LED VS Incandescent lifespan... the LED resembles a different form of hot wire... a fuse.
They call me LED Assassin
To solve the problem is easy with good ol' fashioned CPF advice: buy both and let us know.
They call me LED Assassin
Because you kill LED's ? or Because you kill WITH LED's ? :naughty:
koala
Flashlight Enthusiast
I had fun with lots of rebels. The Rebels have a thin ceramic base, thinner than Cree. It is true that it has less surface but I believe if it is mounted properly it will have transfer heat as good, due to the thinner ceramic base.
I doubt excessive shock can affect the Rebel because there's not many parts that will fall off. As far as I can tell, it's three piece. The dome, die and ceramic base. I believe the dome is liquid then set to become harden. So it encapsulate the whole package.
With Cree there's a ring and the glass dome sits on top of the ring. The glass dome can be pry off. It is held by some sort of gel, similar to those used in Lux3s. You will need quite a bit of force to remove the aluminium ring.
The Rebel dome is half gummy. It can be damage by a bit of pressure with your fingernail. I learned that the hard way... I prefer the Rebel for it's optical properties and it's miniature size. Small is good, small is plenty. But not any smaller ok. it's madness.
I doubt excessive shock can affect the Rebel because there's not many parts that will fall off. As far as I can tell, it's three piece. The dome, die and ceramic base. I believe the dome is liquid then set to become harden. So it encapsulate the whole package.
With Cree there's a ring and the glass dome sits on top of the ring. The glass dome can be pry off. It is held by some sort of gel, similar to those used in Lux3s. You will need quite a bit of force to remove the aluminium ring.
The Rebel dome is half gummy. It can be damage by a bit of pressure with your fingernail. I learned that the hard way...
I prefer the Rebel for it's optical properties and it's miniature size. Small is good, small is plenty. But not any smaller ok. it's madness.
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LukeA
Flashlight Enthusiast
Seconded. Also real top solder tabs would be nice as well.
koala
Flashlight Enthusiast
You mean solder like this? That's the dome I manage to poke with my fingernails...
