Correct, the larger head part is not what was pointed out previously, only that they already have the 26650 sized SP33 that a new triple light could be based upon. I edited my post, re-wording to avoid that confusion.
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Yes we can agreeā¦ I wasnāt saying to re-design or discontinue the current SP33. And I also would love very much to see a triple, or better yet a quad version in its current head size. That is a great idea.
My suggestion was for a new light to satisfy our desires of making a 26650 C8F and that light could be BASED ON the SP33ās design, using the exact same reflector thatās currently in the C8F (hence the enlarged head) so it would have the exact same beam that we love about the C8F and running a 26650, without desecrating the style and shape of a C8. To me the āFattyā C8 doesnāt look like a C8 anymore so why defile it, just make a different light.
Isnāt this just a guessed prediction? Note: Iām not arguing against you, just curious to know if this is just speculation or if manufacturing has actually expressed this. Go to any hardware shop and check for different battery sizes. To me, the variation of sizes appears to have increased over the years. I wonder why people are so sure that that is going to change.
If Samsung took the chemical mix of their 48G and put it in a 26650, we would have a 10A-12A constant output with maybe 6500-6800mah.
Unfortunately, we currently only have 20A 5500mah 26650ās at the moment.
Are we assuming that Sofirn might sell a 21700 version as a complete light with a battery or would it only be as a host?
I notice they offer their 26650 light, the SP33, with an optional battery, but itās an 18650 cell and not a 26650.
One thing I notice about the other three lights on/near the market using the 21700 is that all three of them have built-in recharging. Iām pretty sure Sofirn is not going to redesign their driver to add built-in charging to it which could put a certain amount of buyers off of that size simply because their current battery chargers wonāt accept a cell that long. Itās something to think about.
I think it can be built with built-in charger or attached seat, SOFIRN is willing to listen to our voice; I will contact them to arrange this proposal and send it to SOFIRN.
There are only a handful of good Lithium type cell manufacturers. Some of them are already changing there production to the new 21700 (/ 20700, not sure whatās up with that size).
The 26650 size is, afaik, not being produced anymore by the major manufacturers. Only some smaller and Chinese manufacturers might be producing them, same with the smaller less used sizes like 18350 and 26350.
The 21700 size is superior to the 18650 on efficiency. It has more capacity / power for it size (higher power density)
I donāt think that the 21700 can surpass the capacity of the highest capacity 26650ās. Mostly because they are just a lot bigger. However the 21700 will have (possible already has) a higher power density than the 26650 and thus you could conclude that it has surpassed the 26650 size.
Donāt forget that the size is only 1 part of a cell the chemistry is also important and can result in huge improvements.
Aaaw. Just because an influential m0r0n called Felon Tusk decided to bring to market a new cell formatā¦
I do not know what are the āofficialā reasons behind such new cell format but, beyond any whatever claimings (volume to surface ratio increase and etc), it is obvious they didn't choose 26650 to avoid providing head start to any current industry infraestructure. Packed in honeycomb arrangement there's no actual difference in the space occupied by cells in cylindrical formats.
Since the 21700 format has been brought for the new and soon largest by a long shot market of electric vehicles and such, it was quite logical for all the major players in this industry to follow. No big deal to understand, doesn't it?
21700 better than what? Sorry? 21700 is ā 21Ć70mm, just that. Now, if the thing behind this (cough!) ābreakthroughā were to disappear, no one would @#$%ing care about it.
Except that the chinese manufacturers are catching up the major ones in capacity and current handling (not sure about safety), my Keeppower 26650 6000mAh (I measured 5800) is not that far behind in specs anymore.
Barkuti, name calling is just rude and uncalled for. So you donāt care for all the good things Musk is doing, no need to act it out in this forum.
The 21700 cell is making some surprising impacts, namely Iāve seen a pair of the iJoy 21700 deliver 32A at the tail to 3 XHP-70.2 emitters for right at 19,000 lumensā¦ no other cell that Iāve tried comes close and Iāve tried more than a few of the top choices.
So if the 26650 cell were designed for, but room was allowed for the length of the 21700, itād be easy enough to accommodate both cell sizes and no re-design would be needed down the line.
I looked for 2 fairly new cells with the same continous discharge rates in order to make it as comparable as possible. Apples to apples, so to speak.
Samsung 48G - 4800mah 10A
This 2170 cell (this is the new size Tesla is calling it) has a volume of 24.25mm3.
This equates to 198mah/mm3
LG MJ1 - 3400mah 10A
This 18650 cell has a volume of 16.54mm3.
This equates to 205mah/mm3
So they are pretty much the same - power density wise. The 2170 is about 47% bigger and has about 41% higher capacify. Itās not an exact scale up, but almost.
It seems Tesla is predicting their new 2170 will have a capacity of 5700-6000mah!. I have not seen any batteries with that much capacity. Not yet, at least. Have any of you?
If this turns out to be true, then the power density will definetly exceed the 18650.
So far, I really like this quote from John Peterson.
āBatteries are chemistry in a can and changing the size of the can does not change the energy density or cost of the chemistry inside the can.ā
-Ps, the 20700 was going to be Teslaās new battery size for 2017, but they changed their mind to the 2170. This is what I see reported, Iām no Tesla expert, obviously. Lol
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 Iād 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
TrustFire 32650ās 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 lightā¦ the TRJ20.
The problem, how I see it, is like Barkuti saysā¦ how many cycles are these chemistries going to last? Pretty darn expensive to have to buy a new āengineā 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, itās 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!)
Itās 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 ālesserā 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? Itās 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.
26650ās would be serious contenders if made by the Big 4.
The problem with 18650ās 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 thatās 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?