Update: I definitely melted the tail spring in my H03, the stock spring couldn’t handle the current for an extended period of time. And while it was brighter than my stock H03 by a lot, when the top part of the spring first collapsed, and shortened the path by the coils touching themselves, the light got a bit brighter. So I may have measured 12.5A at the tail, but I wasn’t pulling that much once that spring was in the equation.
It seems I have a bit to learn haha
3v 50.2 K21D 12amp Led4Power driver, 12amp at the tail checked with the Fluke……3,240lm.
Thanks! But wait, if lux=lumens in your setup, then that can’t be right. 324? I’m confused sorry
I was right! 
3,240lm. Direct Read….
3240 lumens
Oh I was dropping a zero! Apologies, thank you!
If you notice in the display x10.
No problem…your welcome!
Spring bypass to the rescue!
HOLY CRAP DOES THIS THING GET HOT!
I'm definitely getting closer to the full amperage now.
Within 10 seconds on turbo it was too hot to hold. This host simply can't handle the heat of full turbo. You guys were right. But I'm still glad I did it! Haha, I'll strap it to my head anyway. On Max regulated it's almost as bright as the stock emitters turbo, so it's plenty useful. And if I need some extra light on a -20F winter day, then I can use turbo lol
Still gonna have to tweak the firmware though. Turn on Andurils “THERM_HARD_TURBO_DROP” to get it to stop cooking me/itself lol
Edit: Turning on that setting definitely helps it stop getting so hot. You only get about 5 seconds of turbo and it starts to ramp down, another double click sends it back up and it gets a little too hot, but then throttles back down after a few seconds. I’m happy with this, I don’t want something to be 200f on my head, and then grab it absent mindedly.
Your using Anduril? Why not set the top of the ramp to something less than Turbo, then not use Turbo. This way you won’t be drawing too many amps and melting springs, etc…
Or maybe switch to a high capacity battery like a 35E or similar. That should limit current plus give longer run time at low levels.
It gets too hot to hold in less than 10 seconds and you’re going to strap it to your head??? :laughing:
I guess I just really wanted to keep it the top of the ramp regulated, but I guess I could raise it a bit more and see where it’ll stay a reasonable temp. Then just watch for the blip to tell me I’ve left regulation, and bring it back down, if I was feeling like keeping it regulated.
Yep lol. I like the idea of having extra lumens available if need be :D
Great that the XHP50.2 does not die in direct drive, as the 6V variant with two batteries.
What battery did you used?
The emitter graph would be the same as with the 6V variant. You have only half the voltage and double current at the same output levels.
I used a 30Q, not fresh off the charger, but freshly charged a couple days ago and not used.
This is one of the most BLF things I've ever read.
I said before, the head strap is a great insulator. I've gotten my headlamp pretty dang hot before realizing it 
I screwed up guys 
I opened my D1, to try a slice & dice on my 3V XHP50.2…
But as soon as I desoldered the LED wires, I saw that the dome was slightly lifted 
I think I damaged it when I removed the “butterfly” centering gasket that I used.
Now I have a UV/blue thrower that heats stupidly fast…
I measured 19A at start !
