I would just follow Panasonic R&D for info about size.
Panasonic + Tesla = Gigafactory
Panasonic NCR20700C is under development.
We will see in very near future about size.
Don’t forget that power tools manufacturers are big customers too.
Samsung INR21700/30T
This is very very cool. 26650 I have always found too big/bulky, even the smallest light designs. 18650 is a GREAT carry size IMHO… but its nice having another option. More choices can never be a bad thing.
I am curious to see how quality levels will vary on these new 21700 cells, since they come from the same factory (at least initially). Unlike ANY other battery… with GREATLY varying quality levels across each size from a half dozen reputable manufacturers and perhaps dozens more less reputable. Being an automotive standard I would assume 21700 would have to comply to very strict minimum standards for capacity and performance. IE… very minimal chance of getting a “dud” cell.
Right now, there are 3 manufacturers of 21700 cells, that I know of: Tesla, Samsung, BMZ
I would be very interested in hearing from our coveted flashlight brands and OEMs who are participating on BLF:
- What is your opinion on the new form factor?
I am assuming that previous/existing flashlights are engineered around batteries, so if 21700 will become commonplace as the next standard, change will be inevitable?
Pretty sure most are waiting to see just how popular the 21700 will become, same as we the buyers are doing at this point.
You can rest assured that there will be lights released before long to support this size, the first ones to do so will sell quite a few if they are quality as well.
At this point I would not expect much more then the selection you get of 26650 lights.
That said if the 21700 does what I think it will and becomes the new standard I am 100% in favor of it. I think it will be far better for all but the subcompact lights, which can always use a 18350 or 18650.
For one thing it will give a more balanced look to lights like the C8 and the grip size will feel nicer in the hand. Not to mention the extra power.
If it does become the new standard, it would be nice if the size was actually standardized itself also. With strict range of minimum & maximum measurements governing it.
I know that is a pipe dream, because manufacture compliance would be optional…. but might as well dream. 
I went with 26650 formats on a few lights. I wanted single cell lights with a bit more than the 18650 could do. 20700/21700 will replace it nicely. I’ll get output and duration far better than 18650. The Panasonic-Sanyo NCR20700A 3100 mah, 30amp perfect for turbo nuke modes. NCR20700B 4250 mah, 15amp for the rest of us.
REALLY WANT A P60 HOST IN 20700/21700.
That’s what makes this case interesting. The automotive industry supply chain is FIRMLY rooted in standardization… EVERYTHING either has a standard or has standards being developed / refined. There are standards for standards even, which sounds crazy but that’s what it is. If your part does not meet spec its scrap and can not ship. So I would be surprised if the 20700 cell length specs were as lose as 18650 and 26650. Especially with Tesla so deeply rooted in 20700 development. We will see though.
Very good points ‘kramer5150’, I had not even thought of that.
And your exactly right, every certifying agency right down to the ASTM will have standards for a ‘21700’ to adhere to in order to be classified a ‘21700’.
It probably will get interesting as we see how it impacts our chose addiction… err, hobby.
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Edit to fix typo…. 20700 changed to 21700
Another nice thing about the automotive world driving these cells is that they have needs very similar to ours, the need for both high drain AND high capacity batteries and/or with a good balance of both. Thus it should press forward the higher drain version of cells.
I don’t see the 21700 replacing smaller cells, but if it’s performance comes close to or exceeds the 26650, then that may signal the closing of that chapter in LiIon cells. Bigger is only useful if it’s also better
What I’m most curious about is whether the first crop of 21700 lights will be expanded body 18650’s, shrunken body 26650’s, or an entirely new size of light with a balanced design to match. Interesting times are ahead however it happens :sunglasses:
Phil
You need to buy another charger with these new 21700cells
BT-C3100 software seem don’t support this new format
Why would you need a new charger?, as long as it fits, if the voltage is supported by the charger, and the needed charging algorithm is not too different, it should work.
Yep, all lithium 3.7V cells use the same 4.2V charge cutout and that is all that matters for charging (well and they you don’t try to charge too quick but few chargers could do that anyways).
That’s like saying since the opus chargers 18650 it can’t charge 14500 or 26650. All current 4.2 chargers will charge them if they fit which they should in most chargers. Especially the outer slots of every 4 bay charger. This cell wasn’t out when opus printed their owners manual but it will charge them no problem just like xstar, liito Kala, nitecore, efest and any charger that can slide to 70mm and charger a 26650 will take them
Well…. here are some Sanyo NCR20700A & Sanyo NCR20700B batteries, right here in the USA; ready to be sold.
EDIT: Ooops, this was nothing new. I had a brain fart and read this as “21700” my bad, :person_facepalming:
I’ve already mentioned the NCR20700B from Sanyo is fitting all my recent charges OPUS 3100, XTAR VP2, SV2, and the Lii 500. They can also fit in a few of my 26650 lights so one can do some basic playing with these until we get a light made for them. I didn’t check them all, but I don’t see any issue, they also fit some of the recent XTAR single slot chargers. A couple old ones they won’t fit in, but those have issues with long protected 18650 cells and that is why they have been retired.
10$ for a 20700 …well…some time will pass till those became popular i guess
The ball is in the Samsung /LG field now i presume, lets see if they`ll follow or continue developing 18650
Oveready is specialised in SF modifications.
Speaking from experience: I bought a 6PD in a clearance and bored the tube out with an adjustable hand-reamer.
Oveready says to aim at a diameter of 18.65mm. I had to bore my light out to 18.70mm ultimately.
At that size a protected 3400 mAh Keeppower slides in and out (it does not fall in because of escaping air).
The narrowest place on the tube is a groove for a second O-ring, next to the thread for the tailcap.
The diameter there is a mere 19.50mm. And that’s the end of the line. No 20700 or 21-70 in this light.
Do remember that the 6P was to be used at 6V, produced bij 2 * CR123A primary cell’s (size equals 16340).