Help me choose... (please)

I want to buy Fred's K2 UY0M (10bucks) or UY0P (5bucks).

M= 3.99v - 4.23v
P= 4.47v - 4.71v

S-bin driven @ 700mA = 100Lumen (to spec)
S-bin driven @ 350mA = 60lumen (underdriven)

U-bin driven @ 1500mA = 130lumen
U-bin driven @ 1000mA = 100lumen

I had the Wiz2 in mind.
(http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=540)

Now the questions:
If I drive the UY0P/UY0M from the Wiz2 @ 937mA from
either 1x 3.6v Lithium or 2x3.0v primaries, would I get 90+lumen ?

For 100 lumen, an S-bin K2 could be driven at 700mA...
(where to get S-bin K2?)

Would I be better of with a U-bin LuxIII ?
What drive-current would be best for it ?

Thanks for the help !

Wouldn't an S bin need the same current as a U bin?? Or is there a quirk in the datasheet...

maybe S-bin is their compare-able to "LuxIII" and U more like "LuxV"...
Dunno, my 0.02 lumens

A S-bin is a LuxI, driven at specs by 350mA - output 51,7-67,2 lumens, also depends on the v in.

I would go with a U-bin LuxIII, driven at 700mA - output 87,4-113,6.

In all cases, the lower the vf, the more efficiency.

So if you go with a U--J or a S--H, T--H (easy avaiable), you will have the best configuration IMO.

With the T or U-bin you could drive the led at 762mA and get the best efficiency in therms of output and runtime.


Best regards

____
Tom

Sorry, I means the S-bin Luxeons at my statement, not the K2's.

Best regards

____
Tom

Ah. I was confused because i thought he was strictly talking about S bin K2's and i couldn't figure out why the drive current would be different....