First flashlight using the new 20700 cell?

[yellow]

Never read of that size till now
:thinking:
Dunno, as with 26xxx cells, i see no real advantage over 18650
--> as long as "normal" use - single xm-l - is involved

And I don't care for any maker, who is this crazy to purchase a light that gets "bad" as soon as the next generation led comes to market?
(Especially when reading in here)
:thinking:
Fivemega, oveready, Solarforce, ..., will do some bodies for us, that will fit c-head ...

 

[toobadorz]

Though many people don't consider 20700-like form factor promising for a flashlight in the near future, I do like this battery to be used in some scenarios.

Let's take the NITECORE TM03 as an good example. Its design is to drive an XHP-70 LED with single 18650, delivering a TURBO mode output of 2800 lumen (actually it's 3000+ lumen according to some reviews). Of course in this mode a lot of current must be offered by the single battery (8~10A, even larger when the battery voltage drops), and so you should use a cell that is capable of delivering ~15A for safety (so NITECORE has a dedicated high drain cell for this light). Then the candidates with largest capacity are Sony VTC6, Samsung 30Q, and LG HG2. These cells have a capacity of 2900~3100mAh (same as the dedicated NITECORE cell).

However sine the NCR20700B is capable of 15A discharging (you can see its curves here), we can surely use this new cell to replace the 18650s mentioned above and gain ~30% or more runtime. And the change in the light form factor is almost negligible. This upgrade is definitely appealing to me!

Similar upgrade can also be made for other flashlights that require a current of 10A+.

And since the curves of NCR20700B is good (many 5000~5200mAh 26650 cells perform poorly under a load of ~10A or above), manufacturers like ACEBEAM/OLIGHT who make 26650 flashlights today can make a "tiny" version of them and offer a longer TURBO runtime. The reason is, as you may know, the ACEBEAM EC50 GEN II and EC60 can no longer output TURBO when the battery voltage drops to 3.7V~3.8V. This is because the ACEBEAM 26650 cell itself cannot stably deliver 10A+ (many others cannot either). Now that since the 20700 can do 15A, ACEBEAM can build a tiny version of EC50 GEN II / EC60 for this cell and remove the voltage restriction on TURBO mode.

 

[NutSAK]

I'm really bad at math, but I don't think that the increase in volume closely correlates to increase in capacity when it comes to MAh. I believe there is a diminishing return but would like to find out more as well. Thing with the 20700 cell is that even if MAh do directly correlate to increased volume, the 20700 still isn't very much bigger than an 18650.

The increase in volume correlates to an increase in mAh, but not proportionally. Demand in the market for performance in one cell, 18650 for example, will drive up the energy density per volume.

The % increase in volume from 10400 to 14500 is nearly the same as the increase in volume from 14500 to 18650 at around 45%. However, while typical energy storage of a 14500 is a bit more than double that of a typical 10400, the typical energy storage of an 18650 is quadruple that of the typical 14500.

 

[cancow]

One of the reasons I never go overboard on any standard/technology is that what was the must have will shortly become obsolete.

 

[StorminMatt]

I believe tesla has dumped the 20700 format and is going with a 21700 aka 21-70. They claim 18650 format was an "accident" and not optimal at all.

Is Tesla referring to 18650's as a whole as an "accident", or just their use of the battery? Because neither is really true. 18650s are actually optimal for their initial major use - laptop battery packs. In this use, they excelled because they had reasonable capacity, but are thinner than, say, 26650s or, of course, 21700s. Nowadays, this is no longer really true. Lipos have taken over the laptop market, and 18650s ARE suboptimal.

As for Tesla, they used 18650s not because they were the very best battery form factor for automotive, but because the wide availability meant that they could be used more economically than other form factors. They definitely ARE suboptimal for EV's. But given the fact that they were a means toward an end (ie they allowed Tesla to produce an EV more economically than other form factors), they can hardly be called an "accident".

Of course, now that Tesla can call the shots more in the battery market, they can move on to something else that is truly more suitable. In this case, it is the 21700. Larger cells mean fewer of them, which means a simpler battery holder and battery management electronics. But keep in mind that using a large number of cells (which the 21700 would STILL require) is probably still suboptimal. It wouldn't surprise me one bit if Tesla makes a move to an even larger form factor in the future.

 

[SubLGT]

As of Nov 2017 there must be around a dozen or more branded 20700 and 21700 cells available on the market.
And still no "mainstream" flashlight manufacturer has adopted the format?

 

[MAD777]

As of Nov 2017 there must be around a dozen or more branded 20700 and 21700 cells available on the market.
And still no "mainstream" flashlight manufacturer has adopted the format?

My thoughts exactly!

 

[eh4]

Nice thing about a 20700 cell powered light is that it'll easily fit an 18650 with a very minimal adapter.

 

[charlieplanb]

As of Nov 2017 there must be around a dozen or more branded 20700 and 21700 cells available on the market.
And still no "mainstream" flashlight manufacturer has adopted the format?

Maybe Im not understanding the statement but wouldent Acebeam L30 fall into that category?

 

[eh4]

I see that the Acebeam L30 fits 1" mounting rings.
I'd think that going to a steel battery tube would solve any wall thickness- strength problem, an maybe cause other solvable problems in process.

 

[degarb]

Wait a few years as I figure that the new battery size will have to replace 18650s in more than just car battery usage. The 20700 is bigger and unless you need a little more power in a single cell vs even more power in 2x18650 batteries it isn't going to happen overnight. IMO unless you need uber runtime or light output the 18650 does fine for most people. I also have got used to the size of 18650 lights and a larger diameter and longer light size needed for a larger cell isn't a plus to me.
I do think for multiple emitter lights the 20700 may have an advantage in that instead of going to a lot of 18650s or bigger 22 or 32mm batteries you can use 1 or a few 20700s and make the light a little smaller.

Uber runtime? Every single 18650 light with a 20 mm reflector, barely can muster enough lux, so must be driven at over an amp to see well-if one's goal is not merely to see. This means the average single 18650 head lamp for tasklighting (not slow navigation or causal use) can muster between 1 and 3 hour.

Well, an average work day for a self employed person is 10 to 12 hours. Carry cells in pocket is plain stupid and impossible if you have 3 workers or family to supply. Then, figure 10 minutes a swap for a nonsmoker and 25 minutes for a smoker. At $30/hr =$5 per swap or $10/day multiply by 200 or 300 days a year. So, $2000 to $3000 per person, annually. Or, a loss hovering around $10, 000 / year for average 3 man crews, depending on days per year, and smoker status.

Now, the time losses will be offset by higher worker productivity, higher worker alertness, ability to perform in environments never possible before, and higher quality work. While no headlamp supplement, will cost tens of thousands per worker, annually. But, we can do sooo much better than the typical wow form factor and runtime. The extra juice of the 21700 will not fix the short runtime issue of the 20 mm single cell, for serious work. But, it will help.

 

[eh4]

So it sounds like bigger reflectors are in order, and maybe battery packs with parallel cell configuration and integrated charging...
And more vacation days for non smokers.

 

[SubLGT]

Maybe Im not understanding the statement but wouldent Acebeam L30 fall into that category?

Yes, it does. Fits a 20700. But not a 21700.

http://www.candlepowerforums.com/vb...ashlight-ACEBEAM-L30-NEW-Product-Announcement

Not a "mainstream" manufacturer, but custom builder TexasLumens has adopted the 20700 format.

 

[MAD777]

I am super impressed by Samsung 21700. For a silly millimeter more, the performance leaps over other batteries. I attached HKJ's chart comparing the best 20700 with 21700, and by the way, both have less voltage sag then the venerable Sony VTC5A.

 

[etc]

Something is off here. A 21700 cell cannot be only 3000 or 3100 mAh.

that's 18650 territory. If that's what you get, you might as well keep the 18650 format.

 

[staticx57]

Something is off here. A 21700 cell cannot be only 3000 or 3100 mAh.

that's 18650 territory. If that's what you get, you might as well keep the 18650 format.

It isn't "3100" mah. It is an extreme drain cell and no 18650 matches it in both voltage level and capacity

 

[search_and_rescue]

Wow this new 21700 battery development sounds very attractive and exciting. I have personal experience in that the IMR 18650 (high quality and high drain 18650) in the Imalent DX80 does read out the voltage sag (on its OLED screen when you triple click) while blasting out its 32,000 Lumens of powerful flood. Yes, 21700 batteries would be "kick-butt" wow.

I'm unemployed and disabled, however, and Imalent DX80 will be the most technologically advanced flashlights I will own and enjoy in my lifetime. My understanding and best wishes to my fellow flashlight enthusiasts for the amazing future. 21700 powered torch. Wow! 👍

It isn't "3100" mah. It is an extreme drain cell and no 18650 matches it in both voltage level and capacity

 

[pipspeak]

Flashlight companies probably follow the lead of battery manufacturers. When Sanyo, Panasonic, Samsung et al stop making 18650 cells then flashlight manufacturers will start releasing lights for the new battery. After all, why come out with essentially the same flashlight with just a slightly larger tube unless you have to? You want higher capacity, then we already have the 26650 lights. Plus, I'm not sure anyone is settled on whether the 20700 or the 21700 will be the next hot size, and in the mean time we'll have many years of 18650 price cuts as competition heats up.

 

[search_and_rescue]

Thank you p for the encouraging treatise above. Yes we have the 26650 too already!

 

[anthon87]

The Acebeam L30 has very good runtimes with the 20700 cell: 930lms for 2:22 min and +1700lm for 1 hour!