Production CREE XR-E Testing

[CaLux]

As my understanding, CREE doesn't allow user to choose Vf value. They said there has no bin code for forwading voltage.
So, if they can keep low working voltage is very good for user.
But, if they can't control well. It may be a challenge to engineer.

 

[AlexGT]

Wow!!! or should I say Holy $hit!!!! That curve is incredible! Amazing! Now where can I get a Q3 bin?

By the looks of it If you have stock invested on lumileds you should really think about selling it, Lumileds may go the path of the dinosaur very soon as word spreads to the high use manufacturers.

"The king has died!!! Long live the new King!!!

"Lumileds RIP"

AlexGT

 

[AlexGT]

Newbie do you have beamshots compared to say a U bin Lux 3?, I am wondering if a Mcr-27L (long) can focus the light to a useful level.

Good work as always keep it up!

AlexGT

 

[CM]

Did you measure those Vf's Kelvin connected at the emitter, or did you measure them at your power supply?

It makes a big difference.

Measured with a voltmeter right at the LED. I know there's a huge IR drop thru the leads from the power supply especially at 1A. I realize my data shows higher Vf but I'm sticking to it. I see some incosistency in Vf since I have two other parts that I went ahead and measured and they're closer to what you got though still a bit on the higher side. I re-measured the data I posted again and got the same results. Maybe a single LED fluke?

EDITED TO ADD:

Two other leds measure 3.50V and 3.55V at 700mA. Still very happy with the output of these. I'm now looking at my S bin and U bins with contempt

 

[goldserve]

I'm curious to know if there is any VF drop after burning in the leds or the heat from soldering the part enough to burn it in?

 

[NewBie]

I don't have much time tonight.
Though, I took some photos that I thought you might enjoy:

 

[x2x3x2]

since u were already testing the input current vs output, didnt u take any beamshots?

 

[NewBie]

Like this?

I stopped the picture way, way down, so you could see the CREE better:

 

[havand]

Nice work. I'm starting to get excited A little not so excited about the lack of hosts though I won't be buying an aleph or a TI McCree so i'm kinda out in the cold on that one. Maybe a minimaglite and just put up with the beam pattern.

 

[NewBie]

Okay, I poked around a bit and found that I did find a loose reflector from McGizmo handy, it is 45mm in diameter.

I know that this isn't a fair comparison, but what I happened to have that was portable is a circuit that delivered 450mA to the CREE XR-E. The exact wattage drawn by this CREE at this current is 1.423 Watts.


I do not know how many mA the Fenix P1 delivers to the emitter, but I had one with a fresh battery I put in earlier today, so I used that as a reference. I just checked the current draw from the cell, and it is measuring 625mA, with the cell voltage dropping to 3.05V. This is 1.91 Watts. I suspect the converter is ~80% efficient, so the power delivered to the Luxeon III in the P1 would be roughly 1.525 Watts- but this is not fact.


I held the reflector in my hand, over the CREE XR-E and thus it isn't centered, and the photo is at an angle, as the truck was in the way. So, we have the larger reflector I used (so please keep this in mind!), and this is what I saw:

Anyhow, I need to run off to bed, maybe I can put together something tomorrow that is a much more fair comparison.

 

[Loomy]

The fact that you ran an XRE way past the recommended 750mA and into 1500mA territory makes me wonder how long it would take to explode in a U2.

And considering how well the L6 mod turned out, I wonder if the U2 reflector is long enough to make a 200 lumen XRE beam look good... just before the LED melts down and your eyeballs are irradiated! Or a Gladius for that matter.

 

[ViReN]

I don't have much time tonight.
Though, I took some photos that I thought you might enjoy:

wow... from photos looks like there is a real thin layer magic phosper sprayed all over including the bond wires. I wonder, if Heat would cause any long term issues (if it's a thin layer).

the 100 Lumen figure at 350 mA is unbeatable as of now

 

[ViReN]

also, why 3 bond wires?

 

[x2x3x2]

finally recieved my 0021 batch from cutter few mins ago.
so it should be 73.9-100.4 @ 350mA, just hope i get lucky with the tint.

also, what does the "U-bin" mean, they wrote that on the invoice. i thought the XR-E bins are refered to with "P" and "Q"?

so i have a question as this will be my first "mod".
am i right to guess that the top is where i solder -ve wire to and
buttom is where i solder +ve wire to? does is matter which side of the + i solder to?

cant wait to see how it goes in a FT-01

 

[paxxus]

 

[270winchester]

Thanks Newbie for the pics.

 

[leukos]

I predict 2007 will be a whole new landscape for LED lights.

 

[jtr1962]

Amazing results and thanks for testing these NewBie!

To show how much less heat these make for a given lumen output let's say the design goal is 80 lumens. You can get that with a typical Luxeon III running at 700 mA. Typical Vf is roughly 3.7 volts so input power would be 2.59 watts. Efficiency is about 10% so you would have to deal with about 2.33 watts of heat.

Now let's do the same thing with a Cree XR-E. You only need about 350 mA. Vf would be around 3.1 volts so power input would be only 1.085 watts, a reduction of 58% compared to using the Lux III. The heat reduction is even more impressive. Since this part is about 25% efficient you would only be dealing with about 0.81 watts of heat, a reduction of 65% compared to the Lux III. In other words, one-third the heat for the same lumen output. :rock:

The good times are just beginning. A few years ago I was waiting patiently until LEDs finally reached or bettered fluorescent tube efficiency. That time has finally arrived. I can hardly wait to see what Cree has in store for us next year!

 

[havand]

I'm not ready to count lumileds out yet....I'm ridiculously happy they now have performance (and pricing competition), but I'm sure they havn't just been sitting around on their hands.

 

[milkyspit]

I'm not ready to count lumileds out yet....I'm ridiculously happy they now have performance (and pricing competition), but I'm sure they havn't just been sitting around on their hands.

Agreed! Competition for Lumileds can only benefit the consumer. Go Cree!
:thumbsup:

Newbie, keep on rockin'! Your testing is a BIG help to many of us. :bow: