Cree XR-E in KL6 host

I don't have much time to talk about this right now but I thought this might be of interest (KL6 courtesy of : )> though he doesn't know it at the time of this posting. Thanks Bill ) :



This is a Cree XR-E in a KL6 host. Based on Cree's spec, the LED should put out about 140 lumens at 700mA. I can't get a good beamshot since this is a temporary mount and I need four hands to do the beam shot. The deep reflector does a decent job of managing the Cree's beam profile. The only drawback is that the hot spot is pretty small but the spill is quite wide. I can't get over how bright the Cree is, it just blows away U bin Lux III's at 700mA and the S bin Lux I's at 350-500mA. I won't even mention the K2's--they're not in the same league at all (unless you live up north and want some light with your heat :nana: )

Here's a comparison shot against a UWOJ lux III behind a IMS 27mm reflector


Cree on the left, U bin behind a IMS27 reflector on right. Both LED's biased at 700mA. Lux reading of 6840 lux vs 9400 lux (don't get too caught up in the lux comparison since the KL6 has a different and bigger reflector)



Using a ceiling bounce test (a better measure of total output), the P2 bin Cree measures about 13% brighter. This is consistent with the Cree bin that I have which is mediocre. P4's should be a bit brighter and I expect some P4's in a week or so.

This is the measurement that confirms what my eye sees when switching back and forth between the U bin Lux III and the Cree.

did you recieve the XR-E from cutter ? does that mean that they started shipping ?

Yeah where did you get it from?
Is it as much light as the LuxV?
Is the small hotspot bright with a lot of light, or the majority of the light unfocused?
We need a beamshot!!!

Patiently waiting to hear about availability of the Cree XR-E. Your results so far are impressive. Thanks.

Are they using a conformal phosphor coating now rather than the coated lens? The picture you posted makes it appear that way.

evan, yeah. And they still have the "global phosphur" (coated lens) which provides a little less color uniformity, but more efficiency. I'm not sure if you can order both P/N's yet.

Does the original KL6 converter board work with the cree? Have you measured the current to make sure it's not being overdriven?

IsaacHayes,

I bought some of the XR Xlamp LEDs that had the coated lens. They put out a nice flood of light with a funky colored corona but overall were not that impressive. I would really like to try some of these new XE's with the clear dome.

Cm,

I know where I can buy them locally but would like to here some more results on these when you get a chance before I buy. I would like to test these against the k2 LEDs I have.

Interesting.....

Nice! I've got a couple on the way..Anyone have any reflector suggestions? I've herad MR-19 mentioned a few times.

CM: Did you mount it on a star or the bare emitter? If it was the bare emitter, how did you mount it?

BTW which lumen specific bin did you get ?

Amonra said:

did you recieve the XR-E from cutter ? does that mean that they started shipping ?

Click to expand...

No, these are not from Cutter. They're my own source who can only supply me a very limited number of samples. For everyone else, Cutter is your best bet.

IsaacHayes said:

Is it as much light as the LuxV?
Is the small hotspot bright with a lot of light, or the majority of the light unfocused?
We need a beamshot!!!

Click to expand...

From my eyes, it's not as much light as a W bin Lux V by any means. Bear in mind though that the sample I have is a P2. I expect P4's in a week or so. Also this is running at about half the power of a WXOT that I'm comparing with. For a low grade bin like I have, it's still impressive. It blows away my S bin Lux I's and my brightest U bin Lux III at 700mA. No question about it.

Beamshot? I'm working on it. I need four hands. Remember, the LED is just held in place behind the reflector. The KL6 is not mine so until I can get my own KL6 to play with....Someone needs to sell me a beat up KL6.

evan9162 said:

Are they using a conformal phosphor coating now rather than the coated lens? The picture you posted makes it appear that way.

Click to expand...

The samples I have use conformal coating.

monkeyboy said:

Does the original KL6 converter board work with the cree? Have you measured the current to make sure it's not being overdriven?

Click to expand...

The Cree's are designed for 700mA though I wouldn't be reluctant to drive them much beyond that. The Cree's thermal characteristics are much better than Lumileds. And I've been overdriving those for years. The KL6 converter is a constant current buck so yes, no problem with the Crees.

havand said:

...CM: Did you mount it on a star or the bare emitter? If it was the bare emitter, how did you mount it?

Click to expand...

Mine are mounted on stars.

If you're going to DIY the mounting, you need reflow capability. I heard of someone using a toaster

The Cree XL3-7090s that I've had didn't respond too well to overdriving. First, they had an exceptionally high Vf (4.5V at 700mA). Driving them at 1A resulted in a Vf of 5V, which started to slowly rise. The I/V curves from the XL3s I have are not at all like luxeons. With Luxeons, past 700mA, you only get small rises in Vf for larger changes in current - the I/V curve looks logarithmic. However, on the Crees, it looked linear. I don't know if the XR-Es would behave the same - it would be nice to see some I/V curves from these.

evan9162 said:

The Cree XL3-7090s that I've had didn't respond too well to overdriving. First, they had an exceptionally high Vf (4.5V at 700mA). Driving them at 1A resulted in a Vf of 5V, which started to slowly rise. The I/V curves from the XL3s I have are not at all like luxeons. With Luxeons, past 700mA, you only get small rises in Vf for larger changes in current - the I/V curve looks logarithmic. However, on the Crees, it looked linear. I don't know if the XR-Es would behave the same - it would be nice to see some I/V curves from these.

Click to expand...

I think you'll like these better:

Vf(V) ILed(A)
=========
2.7 0.01
2.75 0.02
2.8 0.04
2.85 0.05
2.9 0.07
2.95 0.09
3 0.11
3.05 0.14
3.1 0.16
3.15 0.2
3.2 0.22
3.25 0.24
3.3 0.27
3.35 0.29
3.4 0.33
3.45 0.39
3.5 0.45
3.55 0.52
3.6 0.59
3.65 0.64
3.7 0.7
3.75 0.8
3.8 0.88
3.85 0.95
3.9 1.03

Note, the only heatsink was the star so I ran this test *very* quickly. If you plot it, it will not look smooth but it is monotonic

Bump to add beam shots. Sorry, this is a white wall comparison only.

WOW, Look at the brightness of the sidespill. I recognize that the hotspot is 'smaller', but it also looks a fair bit more intense. Pretty impressive! Thanks for the shots!

nice CM.

BTW do you happen to have a shot of the Cree behind a KL1 or KL3 optic? Fro mwhat I have heard from the other Cree thread you mentioned that the beam profile of the Cree works decently with the TIR optic? I have been a fan of the KL1 optic for years now(you know what I'm talking about) and am very curious of what a KL1/P4 hybrid would do. For something in the 3-watt range I really consider many small reflectors to waste too much light to spill.

270winchester said:

nice CM.

BTW do you happen to have a shot of the Cree behind a KL1 or KL3 optic? Fro mwhat I have heard from the other Cree thread you mentioned that the beam profile of the Cree works decently with the TIR optic? I have been a fan of the KL1 optic for years now(you know what I'm talking about) and am very curious of what a KL1/P4 hybrid would do. For something in the 3-watt range I really consider many small reflectors to waste too much light to spill.

Click to expand...

Ask and ye shall receive. Note I have a small mis alignment of the optic and the LED. There's also a little sunset peeking through at the bottom of the pic


Picture is slightly saturated. I drove the Cree at 350mA to get this but it's still too bright
The mounting of the LED in the KL1 head is somewhat problematic. There is a channel that is designed to accept the Luxeon so this shot was taken holding the optic in front of the LED. Eyeballing the distances, I think that the plane of the die is compatible with the TIR optic if you can get the LED in the KL1 head. Some Dremel work will need to be done but I think it's worth it since you are going to get something brighter than a U bin.

wow intense beam in the kl6 reflector, despite the led wanting to throw most its light forward. Guess the deepness of the relfectors is enough to get a good bright beam. I like that beam alot btw, nice tight intense beam, and bright sidespill!!! I'd for sure mod a KL6 to that!

CM, is the beamshot of the KL1 optic using the rounded lens? From my experience, the lens does some funky things and changes the beamshot.