Interesting LED config

[Yodeling]

Any thoughts on these LEDs? Seems like a good deal on Crees and they have independent leads.

 

[Gorgok]

Those do seem interesting, especially as you say they look to be separate circuits.

 

[perkint]

Not a bad price, but far from the best LEDs tho. You can get three ups using XPG2 (white), XTE (royal blue) and XPE blues (if you want a mix of the three) but from a quick look, I couldn't find them except at three or more times the price...

Tim

 

[hllywd]

Free shipping too...

 

[perkint]

Fasttech ae OK -- I've used them for a few things, but they are remarkably slow!!

Tim

 

[Yodeling]

Not a bad price, but far from the best LEDs tho. You can get three ups using XPG2 (white), XTE (royal blue) and XPE blues (if you want a mix of the three) but from a quick look, I couldn't find them except at three or more times the price...

I have no experience with Cree and don't even know if these are decent Crees. How would they would compare to the Rebel ES or the T dies? These do seem like a good solution for anti-disco and could be very cost effective.

Fasttech ae OK -- I've used them for a few things, but they are remarkably slow!!

I use them quite a bit for ecig gear. For me, the HK Post usually takes 5-8 days to the US, while SingPost took more than 3 weeks (SingPost is default but both are free).

 

[perkint]

The XPG2 is about 20% more lumens per watt, looking at the same Q4 bin. If you go up to the S4 bin it is about double the lumens per watt!

All lumens per watt at 500mA & 25°C, just for comparison:
Whites
XPE
Q4 = 87
XPG2
Q4 = 105
S4 = 172
Rebel ES (top bin as no idea what to compare Q4 with)
L = 150 (actual figure from 700mA so probably slightly higher at 500mA which the Cree figures are based on)

Royal Blue (from the binning info on fasttech I think the XPE is actually royal blue, not blue):
XPE
16 = 422
XTE
36 = 575
Luxeon T (again compared with top spec bin and based on 85°C & 700mA so directly comparable it's probably a bit higher)
600

Not sure as these figures are exactly correct - certainly royal blue is not usually quoted as lumens per watt (usually mW). And I'm not 100% about the fiddling I've done to try and bring the figures into line for comoarisons. But it still goes to show that there is a fair difference between the XPE and current LEDs, especially the whites!

You always have to take two other things in to account when trying to work out the best ones to use. Sometimes better LEDs (be it better emitter or simply better flux bin) carry a fair premium (eg XML2s which would have given a figure for white at 185, but are usually at least twice the price of XPG2s), and some times the higher bins are simply not available. You pays your money, you makes you choice...

Tim

 

[salty joe]

Just curious, for LEDs in general how does the best currently available lumens/watt rating compare to that of a year or two ago?

 

[oreo57]

Just curious, for LEDs in general how does the best currently available lumens/watt rating compare to that of a year or two ago?

2006:

Currently:

Cree, Inc. (Nasdaq: CREE) records another significant LED milestone with the demonstration of 303 lumens per watt from a white, high-power LED.

about 100l/w seems fairly common nowadays though.....(60-70 being the break even point w/ CFL)

As you can see, historically, CREE have been announcing a new breakthrough about once a year between February and May mainly, and we normally see an increase of a little above 20 lumens/w.

http://www.candlepowerforums.com/vb...about-to-break-300-lumens-per-watt-in-R-amp-D

http://www.greentechmedia.com/articles/read/can-leds-be-nearly-as-cheap-as-incandescents-by-2020