21700 is the future

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.

18650 is my go-to size, and honestly I am constantly surprised by how small the lights are (I’m a big guy). That said, what I like most in them is the comfort of having 500+ lumens for a while under regulation, even though it takes weeks before I need to give my cells a jolt, moreso now that it’s nearing summer and the sun is dawning at 4-ish AM already.

I think I’d adapt well to 21700 lights if it ever came to it. Moreso because unless I’m DEAD wrong, 21700 torches can take 18650 cells with the correct spacing. Big plus for me on that.

I’m settled and happy with 18650’s and have been for a while. I think the size is good, I don’t want bigger, and the capacity is plenty. I would rather see more 3500mah, or more if that becomes possible, 18650’s than I would more 21700’s. I really don’t want to get into new, bigger lights, and a new size of cells.

Kind of. They need a spacer + a metal extension. Banggood sells something that works: it’s just a small plastic tube with an aluminum cap embedded in the end, which you fit over the negative end of an 18650. Pricey for what it is, though. Cheaper to just buy a 21700 cell.

Another thing I hate about 21700 cells is that it’s really difficult to fit them in chargers. The charger manufacturers haven’t really caught up to it, yet.

Samsung 30T 21700 cells (3000mAh, 35A) fit fine in the Nitecore Q2.

I find a 18650 is ideal for pocket.
Shorts not skin tight jeans. We live in tropics. Usually a light shirt on top.
With a 26650 cell torch for walkabout.
They’re better, with a more comfortable grip for long term hold. Plus more capacity.
and it don’t hurt to carry a spare 18650/26650 in pocket.
They’re not really, going to weigh you down unless you’re a real wimp.

I like to carry a backup in case the one I’m using plays up.
Plus. Twice the range.
Often I go with my headlight. Dual 18650 in band. with 26650 in hand for throw.
Purrfect.

Take one light. (for lightness?)
3 miles from home on tracks on Moonless night. LED, battery, or driver drop out.
NO spare.

Hmmmm. Have fun.

I’m an old sailor.
Everything I carry, outside the front door.
Has a backup.

I disagree. 21700 is not the future.

Solid State batteries are the future.

Furthermore, there will be commercial products available in the year Twenty Twenty.
I’ll bet you Twenty Quatloos!

I ave been a 18650 fan for a really long time… I have recently started carrying lights that use AA or 14500’s for size alone. The Lumintop Tool AA 2.0 have found the way in to the pocket. I have had to adjust my pockets since getting moved in to a manager position requiring professional office attire. Smaller knive, light, pocket tool, ect. The only thing that I have not swapped out for a smaller version is my phone.

While I like the idea of the 21700 not sure if I will ever be a convert.

I like the 21700 in my Wuben TO50R, but that is not an ADC light to me. My prefered EDC size is about the size of the discontinued Olight S15 and S15R, using AA or 14500 cells or up to the size and weight of the FW3A. The MH20 Nitecore is doable. A 21700 will never be my EDC. It is good to have choices to match our personal preferences, though.