Dang! I forgot about how the boost circuit pulls on a low cell! This one wasn’t fresh hot, but yeah, I’ve got several standing in line at the charger so I’ll pull a tail reading on a couple of those and see what the story is. Thanks Comfy.
Edit: my lowest 26650 at the moment is at 3.9V, tail current is up to 2.70A with this one, but yeah I can see what it’s doing and don’t care for it.
That should get interesting.
Boost drivers aren’t the end of the world. Hypothetically an input current limit can keep the load on the cell under control (while also reducing output as our cell runs down).
At 3.5V the tail current is up to 3.10A
My use with these lights is as a 1st Responder. I need/want small single cell 26650 with a very bright option. Throw is really not that much of an issue. Those that don’t understand spill or flood I’ll give an example. Your pointing the light at something interesting like a suspect, with equal spill but twice the lumen output that dim shrub or tree 30 feet to the side is now a better lit with spill and a shrub or tree is now a shrub or tree with someone standing next to it. A turbo single cell 26650 XHP-50 or 70 at 2000-4000 lumens can give that then go back to that 10-1000 lumen flashlight. This is what got me excited about the idea. You ask why not just a 2-4 cell light, well many of us already have back problems with a heavy duty rig. Those large lights get left at home or in the car. I already carry a single cell 18650 duty light, cr123a back up light, Glock 21sf, 2 magazines, Asp baton, two handcuffs, radio, bullet resistant vest with plate insert, inner belt, belt keepers, pocket knife, back up gun, cell phone, pocket notebook. Then they wonder why we can’t catch kids running away.
Not possible unless somebody has access to alien technology. Or maybe witchcraft.
A triple XPL-HI with an ordinary FET driver and a normal 25R 18650 will do bursts of 3500 lumens, though. If it’s an e-switch light with the right UI, even better.
Taser em in the butt. They’ll quit running. Gives ya time to finish coffee, have a smoke, then you can scrape em up and take em in. (I’m KIDDING!)[mostly]{gimmeabreak}
I never really understood the whole “innocent until proven guilty” thing when you catch em in the act. No jury anywhere is gonna know more about it than the people at the scene, catching someone red handed. We had a local cop at a convention that got a little much to drink, tried playing grab a with a waitress, got made and fired several rounds into the ceiling in the hotel restaurant. Guilty. Witnesses galore. But they gave him a paid leave of absence while they tried to figure it all out. Huh? Maybe a big light would help shed some light on subjects like that… Sorry, a memory came flooding in and spilled out all over the epage.
A light like the Raysoon RS-F13, with a wide angle optic or medium angle optic, that would do it. 26650, not much bigger than a C8. Decent build, nice cooling fins. Get someone here to build that boost driver and I’ll build it and donate it to the cause. 
Edit: On Comfy’s suggestion, the 4200mAh Efest 26650 or the new BASEN will do everything the 25R will do. I have triple XP-L HI’s in Eagle Eye X6’s doing a little over 4000 in that burst on a 30Q or 35A. How about a quad? Quad 219C at 4578 lumens should do. (have one in Rey’s Ti X6 that does that on a LG HE-2, 21.1A from a single 18650) Could build it with the ATTiny25a, Bistro, for Police Strobe and Bicycle strobe, plenty of options on how to set it up.
Interesting idea, I like 26650 formats for capacity and amps, with a slightly larger head than body. Makes for easy holster pulling. We’ve got these coming;EC50 XHP70 2000 lumen single 26650, Olight L5 pro at 3000 lumens and a single 26650. As for modes I prefer high/low/strobe with turbo as a double tap and low a constant hold on. Now don’t get me wrong on throw some is always needed for things like runners, address numbers at night, and for what $%& is that out there. Spill is what keeps the surprises down. For those who ask whats strobe for, I use it for location signalling, and getting EMS’s, or other agencies attention mostly.
96 CRI 5000K XHP70s are available. Can’t do that with a triple.
A 4000 lumen XHP70 single cell tube light will be possible when somebody figures out how to make driver components using technology from 100 years in the future.
If the Chinese can get 2000 lumens from an XM-L than us Americans (mostly Texas) can get 4000 from an XHP70 off a AA battery (rechargeable of course). Anyone see a blue police box around lately.
Ha! 
You should really try out a triple/quad XPL light. I think it would do exactly what you want, with the not insignificant benefit that it doesn’t require time-traveling corporate espionage and/or a nanoscale cold fusion reactor.
F2, for sure… I’ve had one of those 96CRI in my Olight SR90 Intimidator with IlluminationsMachines Lum5-90 for a while now.
Well, I don’t think the 26650 would have any trouble at all. If you figure ~5A required at the emitter, you’d end up with ~10A at the cell. The driver would have to be very robust and highly heat tolerant. I don’t see this as impossible at all, just a lot of work and the right components, and a much larger driver than 17mm, of course, with lots of heat-sinking.
Edit: Since I don’t know anything, I did a quick Google search and found this TI boost chip: TPS61088. Would this work at all for a flashlight driver?
Looks like a nice find David, now who’s gonna cram it on a board for us?
Edit: if I’m not mistaken, it’s got an associated 13 components in addition to itself, seriously looks like 17mm is out of the question but 22 might work…. yes?
Well, if we’re talking about a 26650 light, there should be no problem making room for the driver.
That’s exactly what I was thinking! 
Come on tech guys, snatch this thing up and build us a driver! Takes what, 10 minutes or so?
Shoot I’d be happy if it could be fit on 26-30mm even up to 35mm for something like the Courui D01
Pocketable, to some extent, would be far more desirable. The Courui D01 is pdb.
Where did OP go?
I think the first step is to make a large (prototype?) driver for something like a srk. Make it 3A, that shouldn’t be too much of a problem, right?
If that is working properly try to make it smaller and smaller. If you have a working boost driver in de 24/22mm size (or 17mm) then look at increasing the current.
Also for the smaller sizes, to maintain enough room maybe a stacked PCB driver is a option? (Two pcb’s on top of each other.)
I would really want to make a single 26650 mtg2 light. That would be my first mtg2 light…