wow, that's great - I hope someone will figure out how to permanently bypass the protection - though it is kind of big to fit in single cell lights...
edit - wait...so you were measuring output too LEDs and not input to driver? did you measure input, too? because if it has decent efficiency w/ one cell.....even better! thanks!
@dthrckt: Wait, I think I'm lost.. Yes, I was measuring output to LEDs with 2 cells. Measuring input wattage to the driver? Hmm, that would be batteries voltage (under load) x tailcap current = 7.78 x 3.75 = 29-30 Watts?
Calculating for efficiency using Vbatt x Ibatt x Efficiency = Vf x If
Efficiency = (Vf x If) / (Vbatt x Ibatt)
Efficiency= (9.2 x 2.4) / (7.78 x 3.75) x 100 = 75.68% efficient
Not calculating other losses such as internal resistance on the switch and tail cap.
if you don't mind I'll fwd a link for this thread to ian mander. he maintains this driver db http://www.videofoundry.co.nz/ianman/laboratory/research/driverlist.php
so, would you say (at least visually) you get decent output w/ the single cell?
@jufran88: Great build, thanx for sharing! Is it possible you can perhaps test the light with 2 x 18650's and let us know if they can supply the same level of amps than the 2 x 26650's. Also, which Ledil Boom reflector did you use (S/M/W) and where did you get them from?
if you want a tighter spot, the Ledil Reginas work well with XM-Ls, you just have to hand ream out the hole to 7-7.5mm first. I've never actually used a Boom SS (although I have one in my bits box) but I've used Reginas a lot. I personally don't much like the bright spot/dimmer spill of reflectors, so I've moved over almost entirely to TIR optics for my bike lights (different requirements though), but the Regina is one of the best throwing 20mm reflectors for XM-L.
Sorry guys for the late responses. I been away and just got home from work. I have gotten some outdoor shots when me and my girlfriend went up Mt. Hamilton for a drive. I also got some outdoor shots of my DRY. I'll post a comparison later.
Here they are!!
High (Sorry this was the first shot I took and didn't notice it was blurry)
Med
Low
@Lothar: I'll try it! I'll post up some info when I get the chance to do it! I used the Boom MC-E spot reflectors. The OP has been updated with the link! :beer:
@mattthemuppet: Ooh, I might try that. It seems its a bit longer than the Boom reflectors, so maybe I need to trim the inside so the heat sink can sit lower. I noticed with these boom reflectors that there is some light escaping the bottom so I'm losing a little bit of output there.
I thought the squiggles in the pics were the other, littler, photons getting scared away by the big boys. Great build, and thanks for sharing all the details. This is the sort of thing I'd love to do. Just gotta claw through a few other pending projects...