21700 is the future

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.

does anybody know the continuous discharge rate of sofirn 21700 4000mah batteries?

I have so many 18650 cells. It’s nice and small. 18650 is for EDC, anything thicker is for packing in a car, backpack, etc

Absolutely not. Its much bigger and heavier for a difference barely noticeable if you EDC it.

Your math is off slightly. You gave the 21700 20% extra current over the 18650, 5amps vs 6 amps. Then you still get 19% more runtime.

I use a 21700 duty light because I know I can use it all night if need be. Right next to it is a 18650 tactical light. I’m also exploring a 26800 light build for more rural areas. The real issue is 4.2 volts is the standard. For this allows the variety of battery size too be so easily used. Variety is the spice of life. You guys would love the gun forums with; 9mm vs .357 Sig vs .40 cal vs 10mm vs .45

depends what battery they are using… maybe 30A if highdrain ?

well ya thats my question, i dont know which batteries they re-wrapped

I have some very small / pocketable 21700 lights. The Imalent MS03 for example or the Lumintop FW21. And of course the Acebeam W10 Gen 2

Totally worth the small increase in size for 14,000 lumens for the Imalent and 1,200 meter beam for the Acebeam compared with an 18650 light

I would consider EDCing a 21700 but not if it’s over 100mm long.
Last week I’ve been searching for such a light and the Lumintop FW21 would be good size wise.
It did look great until I found reviews. The runtime is simply (very) bad.
I always pick a light that runs a long time on about 300-500lm.
But 2h39 at 333lm isn’t good at all. Many 18650 lights do much better.
I’m not going to buy a bigger light with less runtime….

I’m waiting for a budget 4x21700 flashlight, 4000k, USB, with Anduril!

WildTrail WT3M is 105mm long, triple with a 40mm head…Anduril and very good run times. I don’t pay attention to these specs much but I think it’s the shortest 21700 that I’ve seen. Nice light. They have a single emitter version as well but it’s a bit longer and wider in the head, owing to the reflector.

Here’s a short list of 80-110 lights on Parametrek’s database…not complete of course but always worth a look (WildTrail not shown on his site yet): Parametrek Flashlights

Found the runtimes here: Lumintop FW21 X1L thrower flashilght review | Full Test results included
Then the 21700 doesn’t add much to this 18650: DQG Tiny 4th 18650 xml-2 review

The FW21 totally blows away the dqg on turbo, but that’s something I don’t really care about.

I think some mix up the chain of considerations.

Simply adding a bigger cell for a light that works as well with a smaller cell makes less sense and would be of less good reason, because a larger cell does not necessarily have more energy stored than a smaller cell with better technology.

Deciding to add more Ampere-demanding LEDs has the consequence of needing a battery able to deliver higher current, which potentially is more easily achieved with adding a bigger battery. To increase maximum current of batteries means to make them bigger, with size, weight and cost being limitating factors…

As a result from adding powerful LED, the same runs in a more inefficient range most of the time, running at lower power than recommended. This results in the runtimes being not much longer than a less powerful light with a smaller battery. It’s like driving a racing car in the city traffic. Can be fun for a first impression, but is really inefficientl and not useful.

So, what is the light used for, at wich power setting? This would render the best possible runtime.

So there is no sense in calling 21700 “the future”.

Hmm… 26800 is the future :nerd_face:

Most LEDs are more efficient at lower currents, not less. The driver is another story.

Yes, if the LED is running near the specified maximum efficiency point, but mostly this would even be higher than the power actually used.
Overdriving a LED, as done to max out lumens, is really making it less efficient, so reducing power gives more efficiency, down to the area when the phosphor is not lit enough and starts acting as an optical filter. Remember the (green) tint at low power that goes away at higher power? I am not talking about the blue that comes up when the phosphor is overly illuminated or even evaporating.

wont that be rather heavy?

I will use it in a more stationary manner, like a work light, lamp, attach it to a tripod, etc.