I'd like to hear more about experiences with overdriving a 5w. I put a WXOT in a light engine I already had made for an Aleph with a BadBoy 650 with plans to get another light engine kit and converter board later.
With 2x123 or a 168S/17670 rechargeable, the output is nothing to complain about, but with 2 R123s it overpowers the board, and goes into direct drive.
Coupled with an Aleph3 head, I've gotta say it's the most awesome thing I've ever seen as far as LED flashlights go. Huge increase in brightness, throws farther than a T bin at 937mA with a McR27, but with a spot 4 times as big, and the spill is unbelievable, too.
I've been afraid to run it for more than a few seconds at a time, as it's drawing 1.3A from the 2R123s (only draws 1.4A from a 17670 at half the voltage with the BB650).
If this is going to shorten the life of my LED, say cut it in half, I can live with that. I'm not so worried about heat as I am putting too much voltage to the LED, as it's not going to be run for any length of time on high(assuming I put a 2-stage tail on it).
If I'm risking killing a $40 LED every time I turn the light on, though...well the beam is pretty good at 650mA, too