Is the 21700 format worth the move?

orbital

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It's not just runtime either.
Larger batteries have the ability to keep better amperage at higher output.

Imagine a storm at night, a tree or something smashes into your roof & you need to go outside top thoroughly assess the situation.
You want a light that'll do a couple thousand lumens for a while & not having to worry about dimming or a battery going out.
If there's some big house issue at night, I'm taking a 2x26650 light, so a 21700 light is the next best thing...

There's little downside with added runtime/battery strength in anything battery powered.
 

yellow

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You must not have a Nitecore E4K. That light is the perfect size for getting a good grip and the large
Agreed, looks small (enough)
:)
and I just noticed that it is 26650 host, that I dont like to use.

But the other "problem" is, that (for 15+ years now) I no longer use "ready made" Flashlights;
the ones that are getting obsolete as soon as the next better led gets released.
(exaggeration of course, but it is a bit like that)
18650 P60 host bodies ... (y)

... so I do have to wait till Fivemega (or anyone else?) offers an P60 / 21700 host
(waiting for that quite for years now, does not seem likely, though)
 

Hooked on Fenix

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Agreed, looks small (enough)
:)
and I just noticed that it is 26650 host, that I dont like to use.

But the other "problem" is, that (for 15+ years now) I no longer use "ready made" Flashlights;
the ones that are getting obsolete as soon as the next better led gets released.
(exaggeration of course, but it is a bit like that)
18650 P60 host bodies ... (y)

... so I do have to wait till Fivemega (or anyone else?) offers an P60 / 21700 host
(waiting for that quite for years now, does not seem likely, though)
Nitecore E4K takes 21700, not 26650. 4400 lumens is near the upper limit of what a 15 amp (max. discharge) rated protected 21700 can handle. Lights brighter tend to use unprotected cells which can handle higher currents but have to have a protection circuit built into the light. That means the batteries aren't removable. I try to avoid expensive lights that don't have replaceable batteries. P60 hosts suffer from problems with heat transfer that limit brightness or cook the l.e.d.. If you're okay with the limits in brightness of a Malkoff drop-in, that's fine, but if you are looking for the next best thing, drop-ins are becoming outdated.
 

LEDphile

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... so I do have to wait till Fivemega (or anyone else?) offers an P60 / 21700 host
(waiting for that quite for years now, does not seem likely, though)
I believe Malkoff has such a host, although it's certainly intended for use with their light engines
 

fulee9999

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... so I do have to wait till Fivemega (or anyone else?) offers an P60 / 21700 host
(waiting for that quite for years now, does not seem likely, though)
as LEDphile said, Gene has a 21700 solution, it's called the MD21700:
you can just pop a standard Malkoff MDX head on it, and off you go, enjoy your subsantial runtime on your favorite drop-ins.

Also, Vinh ( SkyLumen ) had a limited ( 100 pieces ) run of a p60 host with 21700, it's called the SLN bulletproof, it's a beast of a host, but a bit finnicky with drop-ins ( they went for around $250 without a drop-in )
1673313668457.png
 

jumpstat

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Coincidently, I have a 21700 light from Wurkkos arriving soon. Its the TS22. I was impressed with how far these budget brands have come and I was really happy when I got the 18650 Wurkkos HD15 and FC12. Their workmanship is quite outstanding compred to those 3x their price range. One does not really need a separate charger as the workkus lights do have onboard charging ports, and they can be made to become power banks too if need be.
 

idleprocess

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I guess today I rediscover old purchases - got a couple Lii-100s that might have the margin to squeeze a 21700 into.
I have determined experimentally that the Molicel P42A will fit into my Lii-100s - it's a line fit with zero remaining mechanical margin. Lights activate for the powerbank function so I assume the contact is sufficient for charge/discharge.
 

MAD777

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Definitely worth going with 21700 as a standard for future purchases. The increased runtime at both high and low amps is impressive over 18650 batteries. Future advances by the battery industry is going to be in the 21700 size, I believe.
 

idleprocess

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Definitely worth going with 21700 as a standard for future purchases. The increased runtime at both high and low amps is impressive over 18650 batteries. Future advances by the battery industry is going to be in the 21700 size, I believe.
This depends on the decisions that the large players make in the market.

The power tool industry was for the longest time all in on the 18650 format for the last decade-plus. There have been some defections to the similar-sized 21700 recently. But DeWalt's transition to pouch cells may tip the industry away from cylindrical cells, following most other consumer electronics. Smaller, lighter, equal power delivery, good enough durability may well prove sufficient while likely proving to be cheaper to make.

Tesla introduced and has subsequently moved away from the 21700. They may maintain some 21700 production capacity to support warranty service for older vehicles, but I expect that to wind down over time. Of course Tesla's partners make cells specific to Tesla's needs (high-density/long cycle life; massive parallelism accounts for peak power demand) but I suspect that slack capacity supplies the secondary market from time to time. Whether this translates to the increasing capacity going to the open markets or the equipment making its way into the hands of other OEMs remains to be seen.

For now the likes of Samsung, LG, Molicel are offering quality cells in the space. There are other less well known makes of course - some of whom may offer a good product.
 

idleprocess

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I have determined experimentally that the Molicel P42A will fit into my Lii-100s - it's a line fit with zero remaining mechanical margin. Lights activate for the powerbank function so I assume the contact is sufficient for charge/discharge.
My examples charge Molicel P42A's without issue. But there's pretty much no additional length margin, thus YMMV as even bare cell length varies manufacturer to manufacturer.
 

orbital

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At high outputs, 21700 shine.
Also, 21700 lights are very close in size to 18650 lights w/ some the same size.
So you get Amp strength & added runtime at no real downside.

Other than really small Li-Ions, I have most sizes of cells,, 21700 cells are my favorite/go-to by quite a bit.
You can charge the high Amp ones at 3A , no problem / ex. Samsung 40T

(must say, 2x18500 are fun)
 

orbital

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Bit off topic,
if say 28700s' at 6200mAh became a thing, would I look at them?
Probably*



*Flashaholic lol
 

WebHobbit

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I got rid of all my 18650s and switched over to 21700s. The only hold outs are my Sofirn Lanterns....and in my mind it makes NO sense to have 18650s in those. I want a 21700 replacement for that too!
 
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