# How to identify genuine CREE XR-E 7090 R2?



## SpaceAce (Sep 22, 2011)

Hallo,
i've ordered a 'CREE XR-E 7090 R2' on star pcb from a small retailer. How can i make sure its a genuine R2 and not a Q5 or something similar?


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## bshanahan14rulz (Sep 22, 2011)

How much do you trust the retailer? That's all you can do.

You may be able to test the LED at 30*C Tj at 350mA in an integrating sphere to test the actual lumen output... Assuming you have a peltier, heatsink, CC source, and lumen meter.


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## SpaceAce (Sep 22, 2011)

Thx.. so the only thing i can do is compare it to my P4 with a digicam (with manual/same exposure controls).


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## bshanahan14rulz (Sep 23, 2011)

You can also try to shine the light on the ceiling in a dark room, making sure not to look directly at the ceiling or the light source, and comparing how well the room is lit up. You should be able to see some difference with a digicam too. Perhaps someone can chime in as to whether or not they make 0.9mm^2 R2 dice yet or if they are all still 1mm^2 dice.


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## JacobJones (Sep 23, 2011)

bshanahan14rulz said:


> You can also try to shine the light on the ceiling in a dark room, making sure not to look directly at the ceiling or the light source, and comparing how well the room is lit up. You should be able to see some difference with a digicam too. Perhaps someone can chime in as to whether or not they make 0.9mm^2 R2 dice yet or if they are all still 1mm^2 dice.



You can get Cree XRE R2's with the smaller ez900 die


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## bshanahan14rulz (Sep 23, 2011)

Ooooh! I've got a new LED on my wishlist ;-) 

Thanks, JacobJones!


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## JacobJones (Sep 23, 2011)

bshanahan14rulz said:


> Ooooh! I've got a new LED on my wishlist ;-)
> 
> Thanks, JacobJones!


 
Only problem is most sellers don't say what die the Cree XR-E R2's they have for sale are using. I ended up buying one with the ez1000 die in the end because I couldn't find a place for the ez900's. 
If you are looking for an LED for a thrower you could take a look at the Cree XP-C Q4, there's a reason saabluster uses these in the DEFT EDC, because they have higher surface brightness than Cree XR-E R2's and therefor throw further. Hope this helps.


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## SpaceAce (Sep 23, 2011)

What's the best way to identify ez900? Looking at the space around the die?





Source: http://www.candlepowerforums.com/vb/showthread.php?270419-Commonly-Used-LED-Emitter-Index


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## JacobJones (Sep 24, 2011)

Yep, that's the easiest way


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## IMSabbel (Sep 25, 2011)

SpaceAce said:


> Hallo,
> i've ordered a 'CREE XR-E 7090 R2' on star pcb from a small retailer. How can i make sure its a genuine R2 and not a Q5 or something similar?


 
Q5 and R2 are adjectant bins. There is no gap between low end R2s and high end Q5s. Even with professional test equipment you would be hard pressed to be perfectly sure...


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## SpaceAce (Sep 28, 2011)

The R2 has arrived. The lense has a scratch you can see from the outside (casts a shadow on the die as well) but its not visible when the LED is turned on (C30/X2000 shell, double lens, flood-to-throw, 3x7135). Maybe its b-class stuff. It was just 6Eur incl. shipping. Once its dark enough i will create a picture for P4 comparison. Looks like an ez1000.





Edit: Picture comparison didn't really help. I'm not sure if this is really a R2. Can't tell if this is brighter than the other P4.


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