On the same <very> intersting thread (White LED lumen testing) at page 6 the results for Cree XR-E R2 bin. It seems better than Rebel in all the currents over 100ma, where I see an impressive 75 lm/Watt at 1A.. 

http://www.candlepowerforums.com/vb/showthread.php?t=89607&page=6

regards
Marco


---------- Initial Header -----------

>From      : piclist-bounces@mit.edu
To          : "Microcontroller discussion list - Public." piclist@mit.edu
Cc          : 
Date      : Tue, 9 Sep 2008 01:11:01 +0100
Subject : Re: [EE]:: Have I got an LED for you ... !!!







> Not hugely impressive, given
> http://www.candlepowerforums.com/vb/showpost.php?p=2139614&postcount=127 shows
> test results from almost exactly a year ago (real ones, rather than
> manufacturer ideal conditions) of an LED which managed over 150lm/W at 20mA
> and 140lm/W at 50mA (oh and also still over 100lm/W at 300mA and 70lm/W at
> 1A!)
> That's also actually about half the electrical input power coming out the
> front as light given an ideal white source is only 243lm/W (the ideal for
> the spectrum of a white LED is presumably a bit higher than that, given the
> blue spike in the spectrum close to the eye's maximum efficiency).
> 
> Chris
> 
> On Mon, Sep 8, 2008 at 1:07 AM, Russell <newsletters@paradise.net.nz> wrote:
> 
> > At the bottom of this page of Nichia LEDs
> >
> >    http://www.nichia.co.jp/de/product/led-lamp-flux.html
> >
> > you'll see an NSPWR70CS-K1.
> > White LED, 7.62 mm square.
> > 3.1 volt typical Vf at 50 mA.
> > 20 lumen typical at 50 mA.
> > (15.1 min to 25.5 max in 3 bins).
> >
> > Lessee.
> >
> > 20/(3.1x0.05) = 125+ lumens / Watt.
> >
> > Sounds of scraping chairs and stampeding feet.
> >
> > 140 lumens / Watt at 20 mA ! :-)
> > 140 lumens / Watt at 20 mA ! :-)
> > 140 lumens / Watt at 20 mA ! :-)
> > 140 lumens / Watt at 20 mA ! :-)
> > 140 lumens / Watt at 20 mA ! :-)
> > 140 lumens / Watt at 20 mA ! :-)
> >
> > Unlike the others on the page there is no link to a data sheet.
> > You can't buy this LED yet but you will be able to do so next month.
> > Nichia have samples available.
> > More scraping of chairs ...
> >
> > I have samples and a data sheet at my elbow as I type :-).
> > Just arrived. Yet to try them.
> > I'll let you know if they are as good as they sound.
> >
> > At this efficiciency about 1/3 of the total electrical input comes out the
> > front as light ! (!!!!!!!!!!!!!!!!!!!)
> > Things are getting good in the LED world.
> >
> >
> >
> >   Russell
> > --
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