Excellent thread!
I’m usually over at cpf under Biker1, but will be here more often.
I just ordered the Emisar D4 in Cyan with XP-L HI V2 3A from Hank. Most likely will be my edc. I’ve been looking for a compact 18650 with lots of power and I finally found it. Can’t ask for more in a high quality powerful light at a great price point. I’ll be feeding her Sony VTC5A’s & Aspire 1100mAh 18350’s.
First time ordering from Intl-outdoor.com and I am very pleased regarding Hank’s quick responses to my numerous emails over the weekend.
I’m looking forward to receiving this beauty 
BigusLightus
I use the Maxpedition Universal Flashlight Sheath 1708, and love it. It is expensive but it works very well, it almost seems to mold to the light.
The D4 has made all my other pocket lights collect dust.
Anyone interested in selling or modding D1/D4s for 20700? I don’t have a metal lathe on hand
Excellent idea!
It may SEEM like an excellent idea, but it’s a lot of work. The 20700 is too long, the light has to be modded extensively to allow it, and then a top 20700 cell isn’t that much more capacity than a 30Q or VTC6. Hardly worth all the effort involved for the minimal gains.
No springs, battery crusher style. Then you can’t switch to the other tubes at will because the tail cap and driver contact have been modified, so it’s dedicated to the 20700. And not ALL 20700’s will fit, this was done for the Sanyo 20700A and the Efest 20700 won’t fit, it’s slightly larger in diameter.
Maybe can we try ask Hank to produce tubes for 21700 batteries too? I think more will sell than 18500 tubes.
21700 cells are very new, difficult to find, and some are comparatively weak in our application. There are now at least 4 different brands of 20700 that would work well for us, as well as some variations such as high capacity or high discharge. So perhaps the 20700 would be a better choice?
One of the attractions to these lights, for me and a few friends I’ve spoken with about this, is the availability of the 18350 tube. In short form it’s very compact and pocketable, much desired. Since there are no 20350 cells (I HAVE seen a new 20650 though) there wouldn’t be a short tube option.
Wouldn’t hurt to ask Hank about a larger tube, but it may be a good idea to start an interest thread and see how people respond to it, then be able to show that to Hank as inspiration to proceed with it. 
My D1 is at the post office but I only go home friday. If the D4 and D1 tubes are the same I’m definitely interested in 20700 or 21700 tubes. It is enough to find one good battery and source like the best 18350 Aspire cells.
My D1 fit the D4 short tube with no issue, but a friend of mine just got the D1 with a spare short tube and it doesn’t work with the D1. I haven’t seen it, so I don’t know exactly what the issue is but he tells me it only screws in part way.
Dale
I’m relatively new here, how does one start a thread on this forum?
On the left, go to Forum Categories, find the category that best suits what you want to post, and start a thread.
I’m old here and still screw it up. 
I’m hoping to see some manufacturers bore their flashlights for 20700 cells and supply a sleeve for 18650 cells. The spring length might pose a problem though. Still, it would be nice to know that if and when 20700 cells start to make headway and are available, lights would be able to use them and the old standby 18650 cells will still work in a pinch.
Is this do-able or am I missing something?
It is pretty doable. A lots of flashlight compatible with unprotected and protected batteries so they capable to run cells from 65 to 70mm in length.
it does not reach a stable balance, the brightness varies continuously
this is what the thermal fluctuations look like, starting at 1000 lumens, per CRX data… search this thread for his posts with more details
Here’s that table
I’d ask which is spicier — the light or the pepper plant — but I know better. That’s a very spicy pepper.
In more detail, the output should look more like this:
But the behavior varies with the emitter type, user-configured temperature limit, environmental conditions, battery type, etc. Output isn’t as stable as I’d like, but it should generally at least avoid damaging itself or the person holding it.
Got my Blue D4 in:
The surface is much rougher than the old green. The old green is honestly my best feeling light, it just feels nice and smooth in the hand. The new one is a little rough on the hands at first, but I think it will be better after several days in a pocket. Frosted optic with the 219C is amazing. I could definitely use this with my head strap now to illuminate my path evenly instead of a narrow circle. Will hopefully make a nice photography light when exploring. I had to clean up the threads a bit because the anodizing made them gritty which wasn’t a problem in my green one which was smooth on arrival. All is well now though. For people that thought the initial D4 was too smooth, the new anodizing definitely lets you get more purchase on it.