21700 is the future

Those of us with arthritis and other mobility problems have to keep the weight we carry down to a reasonable level, so I am actually needing to change from carring a 18650 light to carrying a single AA light. I might finally get a successor to my Zebralight SC52 XM-L. I’m looking at the SC53w. The cells larger than 18650 are definitely not a possibility for me for me now.

I’m liking my Rovyvon E300s Nichia as a home-based light - it is powerful and well-made, but too heavy for carrying on a commute.

Am I wrong to think that maybe 21700 is not as great as I had hoped? I jumped on the Thrunite TN50 but no one else is doing a multiple 21700 form factor. So far the Acebeam K75 and Acebeam K30 GT is perfectly fine with 18650 batteries. The BLF GT70 is also fine with 18650 batteries. I’m starting to think that the 4x21700 is a bit too thick, and the 21700 is only a huge advantage when used by the thousands of cells in a massive battery pack in the Tesla Electric Car? Ha-ha. Maybe the manufacturers outside of Thrunite hasn’t caught on yet. Or maybe the 18650 is perfect and the 21700 is just a little too big for a 4 times form factor; for flashlights? Why has no one manufactured a 3x21700 flashlight yet? -the thoughts of a flashlight aficionado.

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. :beer: 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!

-> https://imgs.xkcd.com/comics/standards.png

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).