Will the 21-70 Battery (a.k.a. 21700) Replace 18650?

This entire topic is about 20700 replacing 18650 which is why I clarified that it is 2017 and the fact that 18650s in laptops form the past is now irrelevant.
Therefore, it does not matter that 18650s used to be used in electronics because they are not today and will not be “replaced” by 20700.
Did you not read the topic title??

Sure I am aware & did read the topic title…. :person_facepalming:
I guess this means you have no answer to what ‘hank’ posted?? You did read & comprehend that didn’t you??
So be it, maybe some informed person will chime in to either verify or contradict what ‘hank’ wrote.
For us inquiring minds that would like to know that is. :wink:

My point is that it is irrelevant to making the 20700 more widely adopted because since 18650 is no longer used there then it cannot be replaced.
The point was not to verify or contradict anything. The point was also not to invite other people to have a useless argument with me when I was replying to a different person that was not you (which is why I used the quote button)
It would be great if you would not jump into random conversations for the purpouse of disrupting a thread and starting arguments…

It would be good if you practiced what you preached also about arguing & disrupting threads. You seem to be pretty good at it yourself. :+1: Seems to me you might even enjoy it.

What I read was a man stated, (in a way that ’to me’ seemed to ask a question); that he had read that the 18650 li-ion size is the same as the 4/3AF NiMH cell originally used in laptop computers.

Nothing more nothing less…… from what I read you did not and have not addressed that in any way.

  • You informed us it was 2017
  • You said all electronics devices use flat cells
  • You state anything still using round is outdated and obsolete

Well the first one is right, it is 2017.

As far as the next two, I think that is a stretch.
It seems to me it would depend on what you considered an “electronic device” whether those two statements are valid or not.

Thank you also…………

My first post (above his) was “Stuff like phones and laptops and tablets do not use 18650s either.”
And then he replied with his post, “I read that the 18650 li-ion size is the same as the 4/3AF NiMH cell originally used in laptop computers.” which I assumed was a reply to mine.
In which case I explained why it does not matter what they used to use, since 20700 (the topic of this thread) would not replace flat cells in those devices.

In this exchange, nowhere did anyone ask you to make a snarky comment such as “That is probably the reason ‘hank’ said… “originally used in laptop computers.”” when the conversation didn’t involve you at all.

Uhm…yeah, well, i hope 21700 will be available soon, with more than 5000mAh and for an affordable price.
It will replace the 3xAAA carriers. :wink: (the taller ones)

OK. I assumed one thing. You said you assumed another. We both probably know the saying about “assume”.

I would not rate my comment as “snarky” either. Actually it was somewhat bland. :wink:

Nope, not about you at all. Just noted as a reminder a lot of tech is designed so as to be backward compatible.

Some prior mention of cell sizes from a thread I started is at: NiMH cells that are "18650" size EDIT and 1.5v / 1.2v drivers?

I’m hoping we’ll see adapters for battery tubes something like SLR companies have made, to let any lens work on any company’s camera body.

One of the delights of the original Arc LS flashlights was being able to get battery tubes to use the flashlight heads with RCR2, CR123, and 2xAA.

kmart will be long gone before 21700 are out there in any great numbers.
most folks around me already have 18650 and even their kids use them now.
as for vaping lots of lipo powered mods out there.
i have a vicious ant and a sigelei here that use them.expect them to become much more common.
genie is out of the bottle already as walmart carries 18650 and flashlights that use them.
adapting to 21700 if they become cheap and common will be a simple production change too.
i doubt 18650 will go away anytime soon with all the power tool mfrs heavily invested in the format.

I’m with the other posters that want to see 21700 batteries with >= 5Ah capacity, and I think the markets will take notice.

I’m pretty sure 18650 will be around for quite some time, and I sure hope I’m right. I’m not sure the current 26650 size will survive.

Right now I just want high capacity 21700 cells that I can get my hands on and I’ll enjoy the ride.

We may see a 5300mAh cell (INR21700-53G ?) from Samsung by 2020, or earlier.

I don’t think most of you are realizing whats occurring here. It is a sea change which will upend whats going on with something entirely different. It’s not that this new 21700 cell is a different size or even better. It is going to change the world. Not because it is a 21700 instead of a 18650 and size matters (ask my wife- wait, nevermind). They will be powering battery banks for houses and factories the same way that the 18650 are powering some cordless tools today. Solar arrays will be charging these battery banks all day and at night you will be able to run your home and recharge your car (same cells) off them. It isn’t just Tesla that will have them. Every EV car and E device will as well. Not just because of size. That Tesla says this is the optimum size is critical to industry acceptance, but because the future will see X3 the power and then later even more, from that size cell. There are multiple streams of R&D working to make them better, along with every major mfg of energy will be working on making them better. To last longer and pump out more power. Faster better quicker. This is huge like we haven’t seen since Edison started to wire cities for electricity. 21700 is the future, as sure as the sun will shine tomorrow. But isn’t not 5000 mah that is in question, but if 10,000 will be there sooner than we can conceive. It ain’t about flashlights. It’s about the world.

Please don’t ask me for a timeline. If the middle east crashes tomorrow, I’d say “sooner’ If they find another Bakken, I’d say ”Later, much later”. It’s coming, and in a big way.

Battery banks for houses use SLA batteries because it is much cheaper for larger capacities.
Batteries for EVs are made from LiFePO4 prismatic cells which have far more charge cycles and more stable voltage curve. They also take up less space than cylindrical cells.
I contacted battery manufacturers for EVs and they have stopped producing more of their large scale cylindrical cells in favour of prismatic.
21700 will never become popular outside of tesla vehicles.

don’t Li-ion have higher energy density then LiFePO4

Very interesting assessment ‘Couchmaster’.
You may very well be on to something, what you say makes a lot of sense. :+1:

One thing is certain…. time will tell. :wink:

The chemistry might in fact turn out to be something entirely new. There are a lot of companies, not just Tesla, tossing large money and a lot of high quality personal at the problem of optimizing power storage in these cells. Tesla was in a race to get product finalized as the development of the batteries was about to head on crash in a race with the development of the gigafactory. They didn’t just try to change the form, but the function as well. They were still testing new cathode material a few weeks before the production was to start I had heard. I suspect that the product they are producing now will be tweaked, modified and improved on a continual basis. I’d love to see a Tesla engineer/chemist share how that went down.

But the Obama administration has also placed a lot of bets on energy via grants. I don’t know what the next administration intends as far as those go but would expect a lot of continuation. I doubt there is a comprehensive list anywhere in the world of everyone who is working on this issue.

Yes, but only last hundreds of cycles compared to thousands for lifepo4.

For something used as often as a vehicle it is nice to not have to spend $5000 on a new battery every few years.

Some test results, at 20A, 30A, and 35A, for the Samsung INR21700-30T can be found here:


In this mini test, it was compared to a Sony 18650 VTC5A and a Sanyo 20700B.

HKJ has posted his more thorough test of the Samsung INR21700-30T:

An impressive battery at high currents.

The thing is it is not just a size game, 26650 never got the attention it need from manufacturer hence it relatively low capability, in theory it should perform much better in capacity and amp draws compared to 18650 but look how much more capacity we gained from 26650? The new Sony 21700 3Tron should be around 5000mah that is as big as 26650 capacity-wise why? because that is where manufacturer now put their research/effort on. So if they leave the 18650 and focus on 21700 i think it is in our best interest that we also starting to use 21700 as a 18650 replacement. As the development on 18650 will be secondary.