Here's what the LED looks like - seems pretty close to pics I've seen of genuine 3V XHP50.2s online:
They're bright, but, well, you know the drill. So I opened one up and soldered a trio of wires into it:
Here's how they compare (mod on the left):
A noticeable, if not astounding difference, and possibly as much to do with solder making better contact than steel when pressed against steel/aluminium. Will I bother to do the other one? Maybe - I'll wait to see if a glob of poorly adhered solder falls off and catastrophically shorts the first one.
EDIT - forgot power measurements:
With a multimeter in place of the tailcap, the modded one is drawing 2.4A while the un-modded one draws 2.2A. Tail-cap on, the modded one is running the LED at 2.9V.
Hey, I EDCed a ’502 forever, nice light. Pretty sure any XHP would be overkill in a drop-in for exactly those reasons: lousy thermal and electrical path.
Thermal, figured everybody knew, but electrical is a bit surprising. Those springs must bite to have such high resistance like that.
I got the 3-mode - it's quite useful at mid-brightness without getting too warm, and fine at full-brightness for a couple of minutes.
I dabbed some solder on the ends of the springs in the other WF-502B, and it hasn't helped much, so the issue is definitely resistance within the springs, not how well they make contact.
