Why does there have to be a one-size-fits-all solution? We have different battery sizes for different applications and preferences. This is a good thing.
You are so right, Rayoui. I think it’s just the recent releases of the excellent Orbtronic 3120mAh 30A-40A, Sony|Murata VTC5D, Samsung 24S, and other fine 18650 offerings have kept me captivated. 
Cheers!
Nah, we should create a new battery size that’s in the middle of all of them, that will be a one-battery-for-everyone solution!
21700 isn’t enough of a size-dump from 18650 to make it worthwhile. Just enough to make it too big for EDC, but not enough to give a good boost to capacity. Yuck.
If you look at popular battery sizes, they all have a decent jump in size and capacity. AAA, AA, C, D. There’s a clear distinction in form and purpose. For lithium-ion, there’s already too much overlap. 21700 just makes that worse.
I like that I can buy a bunch of 18650’s, and use them in tons of lights. I don’t want a slightly different battery size for every light.
Then you don’t have use them. Like I said, different sizes for different applications and preferences.
21700 cells can provide much higher current than an 18650 while still maintaining high capacity. This is important for lights using boost drivers or throwers with very high-current LEDs. Good luck properly driving an SBT-90 light with a single 18650 cell.
For lights that I use around the yard or on the trails, I prefer the size of a 26650 or 21700 light to an 18650 light. Seems to fit better in my hand and the extra capacity doesn’t hurt. That said, my EDC lights are almost exclusively 18650. The 21700 is simply too large for a pocket light (though I do occasionally pocket carry my M2R Pro).
Sure, but the point of this thread is to imply that 21700 is going to replace 18650. If 21700 is the future, then the future sucks.
I think the question to ask is what’s driving the existence of legacy and new liion cells? Our hobby isn’t driving the bus. We largely take what the industry churns out and adapt that that. It’s probably a different answer across cell sizes.
I get Walking In the Light’s point. If its no longer pocketable then it might as well be significantly bigger. I doubt such a thing will exist because they’re not being developed for single cell devices; this is a secondary use.
Do vaping and flashlights make a significant impact on these battery innovations? I’m just wondering out loud.
I do not vape but I bought my batteries online from vape items vendors. All my 18650 Enooks were advertised first for vaping, except for the XTAR with PCB which was advertised for flashlights. I’ve considered “recommended-21700 battery” flashlights. But 21700s are much more expensive than 26650s. So I ended up with five 26650s and zero 21700 for my Sofirn SP33V3. Local market prices played a big role in my choice.
As long as there is a profitable market for these different battery sizes they will remain.
All (decent) “vaping” or “flashlight” batteries are rewrapped LG or Samsung or Panasonic cells which are exclusively made for electric cars and other electronic appliances.
I can assure you that nobody working at the R&D facilities even thinks about their applications in vaping or flashlights.
Molicel marketing department actually looks to care . On the other hand in most other companies the legal department is the only one that cares about vaping. Flashlights just don’t register (probably for the better).
From page 3, of this thread…
This is what LG thinks about vaping and flashlights.
That actually is a battery wrapper condition use safety video.
I EDC the Olight Seeker 2 Pro, (with a clip) and I do not even feel it in my pocket. I wear 5.11 and other pants like them, so it is easy to carry stuff. Glock, knife, light, phone, wallet, keys, etc.
18650 vs 21700
Ultimate question, I’m trying to find answer for, last couple days.
I’m buying my first true flashlight, cannot decide between S2+ and S21A with SST-40.
I don’t care about max brightness - 5A/6A, flashlight is going to become hot in couple minutes anyway.
I’ve compared expected battery life with different settings and drivers, with currently top of the line batteries - 18650 (3500mAh), 21700 (5000mAh).
Which one would you go for, for allround flashlight?
Do you think, the additional weight (body + battery) and dimensions are worth the extra 19% runtime (on 10% and 35% modes it is 7hrs vs 8,3hrs and 2 vs 2,38hrs).
I want to use it as allround light - around the chalet, camping, throw in backpack when hiking, around the house, fishing etc…
My table comparing expected runtimes:
Which one would you pick? So is the 21700 new standard, and am I going with standard which is going to disappear?
No way I can carry a 21700 size light. I was carrying a 18650, but now I can’t do that - I have to lighten my load to AA (with jacket) or AAA (without jacket).
What you can carry while backpacking depends upon your style. If you are always in a hurry to cover as many miles as humanly possible and spend the big bucks on titanium everything, go light. If you slow down to enjoy the blossoms and keep the mileage down, you can carry both a 21700 and an 18650 plus spare batteries. I carry a 26650 thrower because it is really fun to spot animals at night. I might as well just do day hikes if I cannot enjoy it out there at night.
As far as the future, maybe neither will be around when my supply of batteries diminishes. Still, they cost much less than my boots and backpack so no big deal there. But most hikers go light weight nowadays and would not wear the heavy leather boots of 40 years ago (including me), but it worked back then. So try something like a headlamp and change it if it does not suite you. Have fun out there!
Good question. I’m getting a couple of 21700 hosts and will find out soon. I’m liking the 5000 mAh vs 3500 capacity for not that much more volume, but maybe that’s going to be too big for an EDC.
I find my Convoy M2 to be too big for an EDC, but it’s still 18650. My S2+, S2, S3 are so much more easier to put in my pocket. The hosts I’m getting are 126mm x 27mm vs 124mm x 24mm for an S2. That doesn’t seem that much bigger to me.