For EDC I prefer something smaller than even 18650. I’d go for AA (eneloop), something like the venerable Zebralight SC5. I have never been in a situation, where I missed the additional capacity or the higher output of a LiOn powered light.
However, I use my Emisar lights (D4, D4Ti, D4v2 and the D1) pretty much around the house.
SC5 is a great light, but a little fat for EDC. The SC53 makes for a better EDC. Still 1xAA and almost as bright, but thinner and easier to pocket.
Yeah, usually a 1xAA light gives plenty of output and runtime for EDC. My most-carried light is a 1xAAA, because most of the time I’m 99% sure I won’t need a light so why bulk up?
EDC’ing a 21700 light would feel like wearing a ball & chain.
not interested
18650 is small enough, has enough power and energy
period
wle
I’ve gotten to the point where a YLP Unicorn 1.0 is the largest I’m willing to carry for a normal work day. Even then, when it’s not winter (i.e. when it’s not dark when I leave for work and get home after work) I often carry something with a smaller cell type, 18350/14500/16340.
I admit I’ve often wondered if Zebralights were worth the prices asked, but I’ve never bought one (nor even seen one).
Yeh, if I add up what I’ve paid over the years for inadequate and poorly made lights, I could’ve had a couple of Zebralights.
Who knew?
It’s not the future, it’s just another battery size
21700 are way bigger and heavier than 18650 lights. Think in a 21700 alternative for the SC64 or YLP unicorn. There isn’t one close to its size, and if there is one, who needs 5000mAh in an EDC that barely sustains 600lm? I charge my 18650 EDC lights twice a week…
As noted here EDC can have different meanings / situations. This time of year, in my climate, I am always in a winter coat. Don’t think a 21700 is an issue as I could carry my TN4a in my coat pocket without issue. Typically it will be my C8. My SC31B (18650) could easily be an EDC clipped in my pants pocket but is a bit too large for my taste. I think that the new Astrolux headlamp in the group buy with an 18350 would make a nearly perfect EDC even without the need for a coat pocket. (Too many recent purchases and too few funds or I would have one of these!)
Just got a TH20 and I think that might just replace my current true EDC the Ti3(AAA). Found an extra clip that I bought from Fenix store for a Xeno E03 and it works great with the TH20. Not sure yet as even this AA is a bit larger than I prefer for pants pocket carry. I am digging the right angle headlamp thing. Who knew.
Well, I’ve been a fanboy for years. So, IMO, yes, they’re definitely worth it. Just ordered another one (H600Fc) that’s in the mail now! 
Out of all the lights I’ve had over the years, I still use all my Zebras on a semi-regular basis, even ones I bought 6 and 7 years ago (a SC52 and SC52w). I certainly can’t say that about any other brand I have. Yes, they’re not state-of-the-art anymore, but they have the UI I really like, are efficient and regulated, and are bright enough for 1xAA lights (~250 lumens). Actually, I guess they still compare well to most modern 1xAA lights, and get a nice pop with a 14500 in them (500 lumens). The modern Zebras have a much nicer tint than the old ones, though.
If that chemistry tech can come down in price to near 18650 cell (quality) price, then sounds like that could indeed become a preferred power cell. 40+ mins on turbo without overheating in an EDC form factor would be seriously impressive.
I really admire this post.
If BLF had a "like" button, I'd hit it for this comment. 
I just recently had a TH20 modified to run a 219B emitter and it’s a beautifully warm tint. A little less throw, but I was more than willing to trade off some for a more eye friendly tint. It is, after all, designed to be a near-task light. I had no idea that a clip was available that could work for it. Thanks for mentioning!
Count me in as another Zebralight fan. They fly “under the radar,” so to speak. They look a bit… boring, compared to the glitzy lighted switch LED flashlights of today. Comparatively more expensive. And the UI is quite different. But after using Anduril, which I really enjoy, I’m fine with the Zebralight UI. I had an early SC52w that I loved, except for the tint. And these flashlights are seriously a pain to modify (costs more than buying a new light). So I sold it. Got myself an SC64c LE with Samsung LH351D. Very nice tint. It’s a bit longer than the SC52w, but you forget about it. Such a great light all around. And I love that e-switch. I do lean more towards the FW3A, because I’m enjoying Anduril & the flexibility (mods, optic swaps, etc), but my 2nd favorite is the SC64c.
I have to admit, I was tempted to get an SC700, and enjoy that 21700 cell. But it was a bit too big for what I wanted. I also considered the SC600, but the output isn’t an enormous jump from the SC64.
I tried a few Zebralights in the past because they are supposed to have some of the most efficient drivers. I realize I don’t like their UI at all but I can accept it since I’ve been EDCing Clemence’s Tiara Pros that have a similar UI. However, what I CANNOT get myself to accept is the bad tint. Greenish Cree emitters and tint shift. I think if they used a beaded optic, at least there won’t be tint shift. Now if I want a light with ultra high efficiency, I’ll just buy Olights though their emitter options are not too much better than Zebralight. But at least most of them are moddable.
Saw the clip idea somewhere and just tried it. I am also one who likes to tail stand a light. Looking at the TH20 the first thought is that it is not well suited for that purpose. Actually it is the best tail standing light I have ever used. Laid down, technically not tail standing, you can angle and direct the light like it is on a tripod. Way better than a flat ceiling bounce!
It does tail stand beautifully for an angle light, and laid down you’re right about the versatility in aiming it. The clip you mention isn’t available anymore, but I’m going to check some of my older Fenix lights and see if there’s a match, out of curiosity.
I like turtles.
Yeah, Zebralight used to suffer from the “tint lottery” with green and yellow tints in the past. I think they’ve finally solved that. My last 4 Zebras have fantastic tints with very little or no shift. If you get a light with the XHP35 HI emitter, like the SC64w HI or SC600w HI, it’s extremely nice with zero tint shift. I can’t tell the SC64w HI apart from a Nichia 219B light, except that it’s only 80 CRI.
I don’t think I’ve ever got a real dud, but my SC52 and SC52w (6 years ago) definitely suffer from the poor XML tints. Though most of my other (non Zebra) XML lights do as well, including modern lights with the domed Cree emitters.
One big advantange of 21700s is their higher gravimetric energy densities afforded by their higher volume/surface area ratio of active materials.
On the more exotic sides, 21700s from Tesla use an aluminium casing, which makes their cells quite a bit lighter, and even more energy dense, while costing less due to using a cheaper electrochemistry.
Even then, their cells have an energy density of 275Wh/kg, and using a capacity optimized 21700 rather than cost/performance optimized 21700 design, probably get close to 300Wh/kg.
I see two areas that 21700 changed:
1. Multi-cell lights benefit from higher energy density regardless of single cell's dimensions
2. 26650 are pretty much obsolete
What 21700 won't do is replace 18650 in compact edc lights, as several people have already commented.
I refuse to buy any 21700 light for now.
For me 18650 is enough. Flashlights nowadays have 1000-1500 lumens on turbo, which honestly I don’t use all the time because it hurts my eyes. So in reality I get 2+ hours of light on a full battery. Why would I want to use my EDC light for more than 2 hours anyway? And if it’s some emergency I can always switch to lower mode and use it for a few hours.
I can never utilize the capacity of a 21700 battery and it seems useless for me to carry the weight and size around.
For EDC I would say even 14500/16340 are better. I only carry 18650 lights if I KNOW I’m gonna use it at some point.