Sofirn C8F host. 21700 C8F Available

Betting in the 21700 is just that, betting.

The chemistry might be the same, but the efficiency of how much of that chemistry you can safely stash inside the can tends to go up as more R&D is put into the cell and specially in to the cell manufacturing machinery, so that is why my bet is on the 21700 format for higher energy density in the coming years. It might stay the same density, in which case I’d still prefer the 21700 over the 26650 because of the versatility of the size, my preferences on the design of the flashlights and the availability of cells from reputable manufacturers

I definitively think different, but just wanted to lay out a joke with Felon Tusk, too good to pass imho. You know, :-D Tusk ≠ Musk.


We'll see if that turns out into real non-overstated figures, and how much of it will be left after 2K cycles.

Cheers ^:)

TrustFire 32650’s have 6000mAh capacity, and then a bit. They do pretty darn good in power delivery as well. I have 5 of them I think, 3 in one light… the TRJ20.

The problem, how I see it, is like Barkuti says… how many cycles are these chemistries going to last? Pretty darn expensive to have to buy a new “engine” every 4 or 5 years.

I think for this iJoy 40A 3750mAh 21700 cell, they probably use a similar chemical mix to the Sony VTC6 or similar battery. High amperage at the expense of capacity. (Mooch says this cells continous discharge rate is far below 40A, it’s about 24A)

Just general info for everyone:
Battery manufacturers can tweak their recipes to give more capacity such as the Samsung 48G (4800mah 10A) or more amperage like the Samsung 30T (3000mah 35A - which actually does 40A continous! Along with 10-12 milliohm internal resistance!)

It’s also important to note that the best chemical mixtures, the ones with the best efficiency, are the ones by the Big 4. Samsung, Sony, LG and Panasonic/Sanyo. (I hope I got this right). All the other battery manufacturers have “lesser” efficiency. Unfortunately none of the Big 4 make a 26650. That is why they lag behind the 18650 in efficiency and are almost caught up by the 20700 and 21700 which ARE being made by the Big 4.

Can you imagine a Samsung 26650 (which has a volume about double the 18650 at 34.5mm3) with the same chemical mix as the 35E? It’s capacity would be 7000mah and maybe have a 16A continous discharge rate. Compare that to the current KeepPower 26650 with 6000mah and 10A cdr.

Or Samsung could do a 26650 version of the high amperage 30Q. 6000mah and maybe 30A-40A cdr. Compare that to the current Liitokala 5000mah 20A battery.

26650’s would be serious contenders if made by the Big 4.

True, I should have stated ‘is going to be’.

The problem with 18650’s is that they maxed out.
So in order to improve battery performance they needed to go bigger. And, yes Barkuti, the 2170(0) size is more efficient, given the (possible) improvements on the capacity and performance, in the space they have to build battery packs. So that’s the reason why they went with the 2170 size.

JasonWW, I thought Samsung came up with the 20700 cell before tesla came up with the 2170?

But this is going a bit offtopic :smiley:

Well the 20700 was definitely before the 2170. Did Samsung make a 20700 before Tesla did? Idk. If they fid, why? What was it meant to be used for?

We always go off topic. Lol. At least this time we all seem to be learning things.

BTW, my Miboxer C4-12 can take a 72mm cell and my Xtar SV2 Rocket and Xtar VC4 can both take a 71mm cell. These unprotected 21700 look to vary between 70mm and 70.5mm. I am good to go! Lol

I voted for 26650 earlier, but now I think I will vote that both new sizes are okay by me. :+1:

Measured my chargers:
Opus BT-C100: 72,7mm
Zanflare C4: 70mm
Liitokala Lii-500: 70,7mm
Liitokala Lii100: 70,6mm

Jason, my wife is gonna moidarize me and it’s your fault! I ordered 2 of the Samsung 30T’s to try in my triple 70.2, see how they fare against the iJ0Y’s. These are not cheap cells!

I can only see one place that has them and they are $18 each!

Once they start being imported in larger quantities I’m sure the price will go down. You know all the vapers are gonna want them. Lol

I hope they dont burn up your 70.2’s. I would be afraid to run them in my L6 with single 70.2 and FET. You have 3 emitters, so maybe you have more safety margin.

It looks like the 48G would be the better choice in a Sofirn C8F at about $9 each. Frankly all these 21700 are pretty pricey. It’s off putting, but once you buy it you’ll forget all about the expense. Lol

Actually Liitokala 50A delivers less current than Keeppower (really: PLB) “6000 mAh”.
BTW, I’m dreaming of PLB tech in 32650 cell…that would be like 8800 mAh at low currents and 8300 mAh at high.

So, back to the OP… 26650 or 21700 for a new C8F-like flashlight.

This is my personal opinion and what makes sense for me. YMMV

Like many here, I am eager to see the true potential of the 21700 format.

But for TODAY, I choose 26650 and will immediately purchase several 26650 based C8F flashlights.

I already have several 26650s waiting for flashlights/hosts… and prices are very good when I purchase more.

I have zero 21700s (or compatible chargers) and my limited research tells me these new cells are currently more expensive.

If this new flashlight is brought to market in a year or two, then 21700 might make sense.

If this new flashlight is brought to market in a few months, then definitely 26650.

Like I said, a light built for the 26650 can house the 21700 much easier than the other way around.

And yes, Jason, they wouldn’t use USPS either so FED-EX was another $11! $50 for 2 cells!!!

I think maybe Jason hit on something we should think about here. If the new breed of 21700 can deliver TOO much, would it blow emitters in the Sofirn C8F triple?

So if the light is made FOR the 21700 size then it might be somewhat more difficult to find cells that perform LOWER, would be a lot easier and safer all around to have the light made for 26650 and when we mod we could take measure to prevent over-current if we plan to use the top 21700’s.

Just a thought…

You may be interested to see this light I purchased which is 21700/20700 but fits 18650 also:

https://budgetlightforum.com/t/-/50748

It has very unusual springs and battery sleeve to size down. If such a thing as a protected button top 21700 were to exist i’m not sure this would be compatible without changing the springs. By doing that you probably lose out on 18650 flat tops or may run into drop disconnects? I guess the point i’m trying to make is that for you and I this is clever and makes a flexible host but for a ready made light it’s sort of like a jack of all trades master of none. To be fair it does work well with flat top 21700 and flat top 18650 as is.

I suspect when I end up modding this light in the future I will choose springs which fit 21700 really well and if it ends up breaking other compatibility then so be it. I’d rather have a light that does one thing really well.

Your argument makes a lot of sense, considering a product released, you’d have to count on batteries available in the present, and for higher capacity 26650s still win

Yet my preference still lies with “aspect ratio” and portability. I don’t have any 26650 flashlights, but I have a C8 and it feels like it’s on the upper end of the size of flashlight I’d purchase. Both 26650 and 21700 sized tubes would fit our current 18650 cells, so they would still be useful in the present, and for that I’d rather have the narrower of the 2.

But maybe a 26650 version of a C8 or an SP33-like flashlight will make into my collection someday

I’m sure there is or will be. Companies can add protection circuitry to any battery type. Acebeam has a protected 20700 in their L30 light. It is about 74mm long, though.

Oddly enough, within a couple of hours of my ordering the Samsung 30T from IMRBatteries I got an email from them pushing this new cell. So it’s a brand new arrival with limited stock. The point really is that the new 21700 is taking off and they’re becoming available in many different brands now.

If Sofirn were to make the C8F in a 21700 format and supply a cell with it like they did the 18650 triple then it really wouldn’t be an issue of availability as it would come ready to go.

I change virtually all my lights anyway, so cell compatibility is really not a concern of mine.

Not sure protection circuits would work well on a high discharge cell of this caliber unless they have cababilites out there that they haven’t been using to date. With 50A and more on tap, the protection circuit would possibly be highly prone to failure. Not exactly sure how that works.

Hey everybody, just a heads up…. in case someone is thinking about these new Samsung 30T cells, be careful! They are POTENT! Like, wicked monster potent!

I built my triple XHP-70.2 from scratch, right? Found the best results with iJoy 21700 cells at some 32.2A at the tail for 18,940 lumens. I was really stoked about that, but I got the Samsung 30T’s today and all I can say is Dayum! These things will kill a lot of lights, I’m telling ya, fresh charged they did 48.8A in this light for a whopping 21,631.5 lumens!

Pretty sure they will damage lesser emitters than the 70.2’s, well ok, they’ll kill most emitters. Just saying beware that they are beasts and proceed with caution if you decide to get these, ok?

Hmm, 50% more current for… 9% more light?

Still, almost 50A out of the beastie is pretty impressive. :smiley:

RIP Dale’s collection of VTC5A batteries