You dont need to know that (or decide based on that), because all the white leds are more-or-less identical here.
(PS: You mean
current and
voltage, not
output. Output is the lights You get, here the highest
bin means more, at same current and voltage)
What You have to do is:
open the light and disassemble till You can access the led.
Look if the led is mounted onto a star board (which then might be fixed with screws and definitly means: easy work) or if the emitter alone is glued onto some metal heatsink (which means: ask again, more complex operation)
Cheap and therefore good for this 1st mod is to get the led (on Star, as I suppose) from dealextreme.com ("flashlights" / "DIY parts and tools"), or the shop You liked.
A
Seoul P4 led, actual bin should be an "U" (if it is a "T" and cheaper --> a bit less bright. It is on You).
... like this one here:
http://www.led-tech.de/en/High-Powe...3.5W-Star-LED--P4-Version--LT-980_121_78.html
Way to go:
open light, check Star/single led, order new led, get old led out, mount/solder new one in, try light, close it, done.
but (IIRC) if the Seoul P4 is a similar Vf to the original emitter, then all you should get is a bit more output for the same runtime (battery life).
... which would make the tip for
emitter swaps totally useless - effort to improvement wise
When there is still a Luxeon inside a light, the output
doubles with runtime staying the same,
thats why
emitter swaps are the bomb