Maybe, but. not at full brightness the whole time…
example w 18350 data:
since the light is not regulated the pattern is more like
after 1 minute it has dimmed down to 10% of initial brightness, then at lower levels it stretches out for another 30 minutes or more, depending on LED:
> beryllium copper paperclip
Or a Grace Hopper Nanosecond length of the appropriate beryllium copper alloy wire would be a nice addon item.
Everybody should have one. Suitable for explaining to Congresspeople why satellite phone calls have that annoying delay, as I recall she used hers.
https://www.google.com/search?q=nanosecond+wire+length
https://www.reddit.com/r/compsci/comments/4tvrft/how_was_the_grace_hopper_nanosecond_actually/
(how was the length actually measured)
Video: Grace Hopper to Programmers: Mind Your Nanoseconds! - High Scalability -
Yep, just barely too small to fit the tail threads.
I wish SolarForce hadn’t quit making/selling their deep carry clips.
As far as i’m concerned the d4 has replaced all my other edc .Once you get past the turbo amazement stage this is a fantastic light.On mine you can run it up to 800 or 900 lumen and run it indefinitely without it getting to hot or ramping down. Not to many lights this size out there will do this.
I shouldn’t post when I’m frustrated. Sorry, cdjaney.
Things are better today though. I’ve been prototyping new toys. 
Thanks Jon. I find this to be an absolutely amazing light.
cdjaney, Banggood has them in stock. Or at least they did this morning.
Looks like you can pre-order the Emisar D1 Mini-thrower on mountian
This light is amazing but I think my light isn’t performing at the max. I’ve scanned this thread but can’t seem to find any mention of how many amps, via tests with the XP-L HI V2 version, are actually being observed on turbo. Richard just sent me the VTC5 and the 25R, I cycled them a few times, charged both to 4.2V, put the meter to it and neither one produces more than 10A (barely) with my D4, purchased from Hank. That’s only 2.5A per emitter. Should I return this D4 to exchange for another?
Long thin multimeter leads?
Does your D4 light up a room like a 60-80w incandescent bulb when pointed at the ceiling at max level?
If it’s a common DMM, those are terrible at measuring anything more than a couple amps. You’ll need a clamp meter for that, and probably a thick copper wire held very firmly in place of the tailcap. Preferably soldered on, but if you can get enough pressure and contact area it might be able to provide an acceptable measurement.
Lumens are a more useful measure for this sort of thing.
Yes 
and yes
Should be cool then 
Or you could take it outside and check the performance. Mine has a 30Q in it (XP-L Hi V3 1A) and it will easily light out to 100 yards with no other light pollution (I live rurally).
Most common DMM can’t test current draw over 10A anyway without blowing a fuse so be careful. But like TK said, you should use a clamp.
Time to get a new meter. Any suggestions on a budget brand?
This light really is amazing but this is the first one I own where hand cooling is akin to fire walking! I bought a hose washer pack from Home Depot for $1.19 (I use the rounded black ones) and they serve as fall protection, gripping surface as well as roasted skin preventers! Come to think of it, I may use one for the lanyard attachment point at the head.
I know you’ve heard it a few times but great job! Thank you TK!
Thank you CRX!
BrianK, Great suggestion… On my way out!
I got a cheap one, a HS1010A lux meter, and made sort of an “integrating milk carton”. It’s not high-quality, but it works well enough for my purposes. For info on making a nice integrating sphere, look at djozz’s threads on the topic.
This would probably be a good time for the weekly reminder to everyone that Hank of Intl-Outdoor designed the light, and Tom E wrote most of the firmware for it. I just fixed a few little things at the last minute and wrote a review.
I figured there would be a lot of reviews of this light, so I put “TK” in the title to indicate that it’s my review, but it seems people may have the impression that it’s my light. But no, it’s just my review.
And an excellent review it is! Thank you Hank for your skill in bringing us this mastery of form and Tom E for the culmination of a most useful set of functions.
How hot does it get? Is it too hot to hold after 20 seconds? Is it doing a temperature step down? You can use the temperature check to find out the temperature in C after running it for a bit.
My first D4 was faulty and couldn’t get too hot to hold. It appeared to be half as bright as it should have been. But even then it could light up a room by bouncing it off the ceiling