Go with 14650 for longer run time.
Powering it with 2 cells would be tricky, you'd need either a tiny buck driver if the 3XP is configured for parallel, or a tiny boost driver if it was set up in series. And tiny drivers tend to not have enough output to make these triples worthwhile. (unless you can build a 'L-style' parallel adapter for the inline cells, and run the 3XP in parallel, with either direct drive or a linear/constant current driver)
Any idea where to get a quality protected 14650? All the threads about them here died without replies.
As far as 2x 14500 goes,
Something like that parallel adapter someone made for their DST? Would there be any downside to running a triple in this manner? I’d probably use KP protected cells.
Man loving that S2 mod!
Did you open up the front area (wider diameter) a bit to allow more optic to come through or does some of the front overlap the optic?
I’m wondering instead of shortening the head, why not add more heatsink to fill the gap?
Unless of course the goal is to get as small as possible.
Comfychair, I don’t know how you get your triple beams so clean looking and artifact free.
Better than any other triple optic beam shots I’ve seen.
Yes the 'L' adapters work, if you have room in the tube beside the cell for the straps. .021 copper sheet works well, it's thin and you can form it into a semicircle to hug the cells and make it wide enough that it'll still carry lots of current. I made one for a 2x18650 TR-1200, but using a clicky switch PCB to join the two halves in the middle. I drilled out all the vias connecting the two sides of the PCB, and soldered the straps onto it.
Front strap soldered to the rear face of the PCB, rear strap soldered to the front face. Insulated with clear packing tape which was a mistake, something in the adhesive doesn't like copper and made it turn green right quick. Use the orange/brown kapton high-temp tape.
Two cells in parallel appear electrically the same as a single (same voltage), but with double the capacity (and double the amperage). You can use any 3-4.2v driver.
The pill/optics assembly I ended up with fills in the entire unthreaded area in the front of the head, and the head was cut to leave just enough threads to fully cover the front end of the battery tube. If the pill were longer instead of chopping the head it would be sitting in the threaded section and so wouldn't do squat to help with heat transfer, so it would basically just be wasted space and a light bigger than what it needs to be.
Yes the front opening was enlarged a bit. I'd first planned to keep the o-ring in front of the lens so the cut was made to leave just enough lip to cover the o-ring, but it's a much more solid assembly without the o-ring and the lens glued in with clear RTV. Won't ever come out unless you want it to, yet still easy to remove. Which is a good thing, considering with a pressed-in pill (which is pretty damn tight) the only way to get it out again is to press the whole thing out rearward in the vise, and that means pressing against the lens. I only did one test assembly during the build but the pill pressed out fine.
The head & tube don't actually butt together when assembled, it ends up about .003" shy. The front face of the tube seats against the rear face of the pill.
See the nice anodizing on the front face? grrrr....
If I’m running a triple DD with one 14500, do I use series or parallel? …or does it matter?
Series would require a boost driver - it would need around 8 volts before you start to get any light (and since Vf rises with current, to run a series string of XPG2s at 1.5A it would take ~9.5v).
LEDs in parallel use the same cell config/drivers as a single LED.
Thanks comfy. It had just dawned on me that I had no idea.
Alright, thanks for that info. I didn’t even think about the extra thickness the bracket has. Currently the tube is very snug on protected 14500 alone (It almost rips off my AA nimh wrapping). I guess I’ll try my luck with the chop then. 
Thanks comfychair, mod looks great even with the scuffs to the ano.
I like the wider opening in the front and the use of RTV glue so no need for front lens = more light otf.
Very impressed with your mods.
No the glass is still there, just sealed with RTV instead of o-ring. I'd only omit the lens if that would let me cut the head another ~1.5mm shorter like I did on the TR-801s, but on this light the unthreaded section plus the length of thread on the tube is what determines the overall minimum length, the pill just fills in whatever space is left over.
NightCrawl: the link did not work because BLF screwed it up, so I put it on bit.ly and it works now.
At least it did not kill itself which is surprising :bigsmile: Nor cause a fire.
I thought the front face was milled off 0:)
But now that you point out, eh, looks like it’s just spray painted.
You left the glass lens there in front of the Carclo? And sealed it with RTV?
Didn’t want to make a bigger spacer instead?
I’m still waiting for the 3XP boards 
Have optics and Nichias but not the boards nor the spare host yet.
Nichias won't do this...
Leftover piece of heatshrink tubing. Actual time around 45 seconds. Pics don't show the smoke coming off the tubing while that was happening. And those are only the 3D/5000k XPG2s, too... lol
I have not the slightest clue how the hell the little plastic TIR survives in there.
The TIR is polycarbonate. Hardly “plastic” at all in the general sense.
That’s a nice heatshrink torch you have there. 
That comes in handy!
:bigsmile:
The lenses are made to withstand high temperatures.
Now using some cheap Chinese lenses could deform them a little, but even those should be from the same/similar material and survive fine, but you never know 
Why is it throwing so much heat?
Why Nichias do not?
I can right now say, they do as well.
Relatively quickly too, no smoke though, so probably not as much.
No idea what current they get, it’s a triple in series on a modified IS aluminum board, there is a point where they are starting to get more blue tint but no increase in brightness, so just below that point. The heatsink does get hot when it runs on max continuously.
I suppose more heat is put into the heatsink than emitted out.
Doesn’t seem to burn paper.
I got goodies today!
Will I be able to make this work, I don't know. It'll depend on if I can get the bent-under legs to land on top of the 3 traces for the stars or not. Attaching it once that's worked out & space won't be a problem. Thickness of the switch is .090" including the legs, thickness of a 7135 is .060". Am I derailing my own thread? Probably. :p
Is there no end to the madness in this thread?
Luv it.
Ok, professing my ignorance…what the he is that thing and what is it for?
Edit: Nevermind, I see.