XML-2 emitters?

[DKlaser]

I have seen these XML-2 emitters and was wondering what the lumen output is supposed to be at 3a of current?

 

[datiLED]

I have seen these XML-2 emitters and was wondering what the lumen output is supposed to be at 3a of current?

Interpolating from the CREE XM-L2 datasheet, the output is about 975 lumens at 3A.

 

[DKlaser]

Then what was it for a regular XML?

 

[Jayls5]

Interpolating from the CREE XM-L2 datasheet, the output is about 975 lumens at 3A.

Out of curiosity, how are you estimating that number? I just see reference values for 2A and a graph of luminux flux % vs current.

 

[hellokitty[hk]]

Right you just look at that graph you were looking at.

 

[Jayls5]

Right you just look at that graph you were looking at.

I see it's about 325% relative luminus flux. I suppose you just used the 85 degree 700mA rating for the U2 bin of 300 lumen by 3.25 to get your estimated number of 975 lumen, so that would be the number for cool white tint... correct me if I'm wrong.

 

[DKlaser]

I was thinking at around 3a that some of these new XML2 emitters were doing like 1300 lumen?

 

[datiLED]

I see it's about 325% relative luminus flux. I suppose you just used the 85 degree 700mA rating for the U2 bin of 300 lumen by 3.25 to get your estimated number of 975 lumen, so that would be the number for cool white tint... correct me if I'm wrong.

You are correct on all points. CREE bins their new LEDs at 85C, and those are the numbers that I would feel comfortable using for a quotation of estimated lumens.

 

[DKlaser]

Ok so lets get this down to the basic question I was wondering here.... What is the lumen difference betwen the highest producing bins of the XML and XML2 emitters @ 3a ?

 

[Jayls5]

Ok so lets get this down to the basic question I was wondering here.... What is the lumen difference betwen the highest producing bins of the XML and XML2 emitters @ 3a ?

If we are going strictly by the datasheet, the way to compare the two emitters with the least variables would be to take the 25C temp rating from both emitters. The new XML2 is binned at 85 but still has 25C reference values.

XML: 300 luminus flux @ 700mA current with a temp of 25C
XML2: 341 luminus flux @ 700mA current with a temp of 25C

Now reference the graphs showing current vs luminus flux.

XML: appears to be 325% exactly. 300*3.25= 975 lumen @ 25C
XML2: also appears to be 325% exactly. 341*3.25= 1108.25 lumen @ 25C

The 25 degree rating is not realistic though, since it will be much hotter on 3A operating temps even with good heatsinking. This is probably why CREE gave the specs at 85C for the new XML2. As discussed previously, the XML2 is rated at 975 @ 85C. The old XML has the same number, but that's at the unrealistic 25C temp.

 

[LEDAdd1ct]

Actual test at three amps in an IS:

Link