# new Cree XM-L U2 on pur and gold plated copper core board



## ichoderso (Dec 9, 2011)

Hi, yesterday I got a sample of this new XM-L on a copper core board.
In the next days I will made some tests and will write the results here.
For the first, you can read some of my tests from a preproduction run in our german forum
http://www.messerforum.net/showthread.php?t=96681
If you have special questions, please ask me!

Jens


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## yliu (Dec 9, 2011)

So you can drive the LED harder without overheating it right? I'm guessing you'll need a decently big heatsink as well...


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## yellow (Dec 9, 2011)

the "best" were, if the slug would be directly the "board".
One barrier less, thus extremely better heat transfer
(considerably better than whatever fancy material is used for the additional board/star)

But then the size of the led will be "bigger"
and the slug has to be electrically negative, or course
:thinking:


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## bose301s (Dec 9, 2011)

yellow said:


> the "best" were, if the slug would be directly the "board".
> One barrier less, thus extremely better heat transfer
> (considerably better than whatever fancy material is used for the additional board/star)
> 
> ...


Electrically neutral or isolated, saying electrically negative conotates the it would have a negative voltage which you would not want.


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## ichoderso (Dec 9, 2011)

the center "heat transfered" part of the LED is direct soldered with the copper board, no isolating barrier .... and this part is electrical neutral on the Cree XM-L....(was negative on the SSC P7 how i know....)

Jens


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## bose301s (Dec 9, 2011)

ichoderso said:


> the center "heat transfered" part of the LED is direct soldered with the copper board, no isolating barrier .... and this part is electrical neutral on the Cree XM-L....(was negative on the SSC P7 how i know....)
> 
> Jens


I know, this. Seoul also used to have the star board be negative on the P4 when they first came out, burnt a few up at an internship with a lighting company prototyping stuff when we didn't know that. Was a dumb idea on their part, should always be electrically isolated.


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## ichoderso (Dec 13, 2011)

Hi, since some days, you can order this item offically, here is the link:

http://www.led-tech.de/en/High-Power-LEDs-Cree/CREE-XM-Serie/CREE-XM-L-U2-on-Copper-PCB-LT-1790_120_170.html

other color bins, neutral and warm whits will follow soon, so my info from the manufacturer...

Jens


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## DM51 (Dec 13, 2011)

This belongs in the LED (emitters) section, not LED Flashlights. Moving it now...


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## mrradlos (Dec 14, 2011)

Now this would be nice without dome ...


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## monkeyboy (Dec 14, 2011)

The luminous output is reduced without the dome. What would be good is a side emitting optic like the old luxeon I.


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## uk_caver (Dec 14, 2011)

monkeyboy said:


> The luminous output is reduced without the dome. What would be good is a side emitting optic like the old luxeon I.


With a large die, would a side-emitting optic (and the reflector it fired into) have to scale roughly in size with the die to keep a similar (scaled-up) emission geometry?


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## monkeyboy (Dec 14, 2011)

uk_caver said:


> With a large die, would a side-emitting optic (and the reflector it fired into) have to scale roughly in size with the die to keep a similar (scaled-up) emission geometry?



Scaling everything up would give the same beam angles. 

e.g. If you could perfectly scale a side emitting luxeon I and reflector by a (linear) factor of 2, it would give an identical beam pattern of twice the diameter but at twice the distance. It would be roughly the same size at the same distance.


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## ichoderso (Jan 2, 2012)

there is a "Day Trade" for this item today, with a bit luck, you can get it for Eur. 6-7,- (about USD 8,-)

http://www.led-tech.de/en/daytrade.html


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## tobrien (Jan 2, 2012)

so is the U2 bin simply brighter or is it more efficient or both?

is it essentially the 'new' S3?


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## bshanahan14rulz (Jan 2, 2012)

Think of it this way: it is more efficient at turning electricity into lumens, therefore for the same electricity that you put in, you get more lumens out. 

They are brighter because they are more efficient.

If the thermal slug can't be soldered directly to the copper core, it would be nice to see a larger trace area for the thermal pad. Or did I miss it?

Waiting with baited breath for test data 
(Gotta stop eatin' those earthworms and minnows)


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## alpg88 (Jan 4, 2012)

bshanahan14rulz said:


> If the thermal slug can't be soldered directly to the copper core, it would be nice to see a larger trace area for the thermal pad. Or did I miss it?



but they are soldered directly to the copper core


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## Epsilon (Jan 7, 2012)

Look at led-tech.de for a picture of the thermal path differences . Will upload it when I'm not on my phone .


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## Pöbel (Jan 7, 2012)

look at the test done in the first link. Heat conduction is great, you can drive them with 5A and the LED will not overheat granted your heatsink can handle the load.


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## Epsilon (Jan 8, 2012)

Allmost forgot:


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## gabtrac (Jan 10, 2012)

ichoderso said:


> Hi, since some days, you can order this item offically, here is the link:
> 
> http://www.led-tech.de/en/High-Power-LEDs-Cree/CREE-XM-Serie/CREE-XM-L-U2-on-Copper-PCB-LT-1790_120_170.html
> 
> ...



Hi Jens,
I'm very new to ALL of this, but I need to manufacture some lights that work off 12V. I'm pretty sure the LED's I need are the CREE- 941-XMLAWT0000LT40E3. 
I am a film-maker and will be shooting in very remote locations where I need to light big areas. My research tells me that the LED above is the brightest most efficient available. My problem is, I have no idea what parts I need or how to configure them. I will build my own housings. But electronics are not my strong point. I am hoping to arrange 3-6 or more (most efficient) of the LED's in each housing and would like to make up about 4-5 housings to start.
Can you help me?
Thanks,
ak


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## Epsilon (Jan 12, 2012)

Very offtopic, but you probably want good coloring as well. These LEDs aren't suitable for that application. Look for high CRI LEDs for those applications which need accurate colors.


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## ichoderso (Jan 16, 2012)

There is a NW version in the day trade today

Jens


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## Nos (Jan 16, 2012)

Bought 3 for a little more than 18€


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## BvanderG (Jan 23, 2012)

Does this sort of thing also exist with warmer bins? It seems the LED-TECH boards have bin 3 at most; I'm (urgently) looking for an XM-L of bin 8 on a board.


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## las3r (Jan 26, 2012)

So for the people who bought these what did u use them in, and how hard are u pushing them ???


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