NiMh 1.2v is STILL the most underrated battery......

Back to the original premise of the AA Nimh being underrated (basically being the 18650 of the world) I will still contend that a properly boosted AA Eneloop is superior to a 14500 direct driven format.

Now if Eneloop or Fuji put out a retail 18650 size version of their exquisite AA, I’d be all over it.

3 to 4 x AA Nimh in a battery carrier type stubby high performing flashlight almost gives me a Woodrow. I mean how much continuous uber-lumen runtime do you really need 99% of the practical time, especially heat dissapation wise?

Breaking records is ok. EDC practical use?

Give me a well-boosted AA NiMh or two. The boost is good. :laughing:

Developing new improved chemistries cost money and you need to recoup that cost by making the most money from the batteries you sell in turn. 18650 is used everywhere and has a huge market. 14500 is a tiny market. A manufacturer only wants to make 1 size of cell to maximize the rewards from economies of scale.

There is practically no money to be made in oddball sizes. As a result many of the weird little cell sizes will use older more generic lower performance formulations.

Right now we are entering a very interesting period since Tesla is trying to push a move away from the 18650. So you’ll see 20700 and 21700 cells with the latest and greatest because someone is lining up to spend billions on these cells. But only hobbyists and solar light manufacturers care about 14500.

If you want good 14500 cells then first become an eccentric billionaire and then blow your entire fortune on a giant order :slight_smile:

So the 20700 and 21700 will have a different assumably superior composition while also being bigger and heavier than 18650. Seems to me outside of Tesla and maybe power tools this lithium push doesn’t do much for our little world here.

On the powertool side going brushless has been a big deal. Improvement of drivers and LEDs for lights kinda the same correlation. Going from 18650 to 20700/21700, meh, I bet not nearly.

“….become an eccentric billionaire and….”

Yeeeeeah. I’m still working on that.

:laughing:

Yeah, I don’t get the excitement some have for those new formats. 18650 is already on the large size for EDC or even pocket carry on walks. I don’t want something larger. Yes, it will give you more capacity and current, but an 18650 already seems plenty good enough for 99% of uses.

You might as well go 26650. This 20700/21700 upcropping sorta reminds me of Betamax vs VHS.

And at the end of the day we all went DVD. :sunglasses:

So all the gazillion lights in 18650 tubes are basically hosed if this new size takes over.

Let’s hope not. It’s stupid.

And just becuz Tesla’s gonna do it means it makes more sense for everyone else too. Notta so much.

I can see the 14500 cells not being much better than a high quality eneloop nimh, I’ll agree with you on that.
18650s though are still far ahead.


2170 cells are actually not any better than 18650s, despite all the hype.
Their chemistry is the same, energy density is the same, energy per volume is the same, the only differences are

  1. it is way more expensive per Wh, since 18650s are much more common and 21700/20700 cells are rare
  2. they can deliver higher currents continuously, similar to 26650s or high discharge 18650

The cells tesla is using are actually NOT the best, they opted to go for a more economical chemistry from panasonic which is not NCM.
It is very similar though, hence the similar energy density.

The claims about 5750-6000mAh per cell from that one random youtube video are actually false.
The actual capacity is closer to 4600-4800mAh, like the samsung 48G

As I hunched, the 20700/21700 hoopla is full of poopla. :laughing:

And no I wasn’t inferring that a AA Nimh could go toe to toe with an 18650. Ok well maybe with an Ultrafire it can. :open_mouth:

Why do you consider 21700’s stupid? Just because it’s larger?

I do agree however that for travel and EDC purposes 18650’s are already on the big side. I’d actually almost rather see more research go into increasing 14500 capacity.

Comparing a mid drain 18650 vs a 21700, you get about 40-50% more capacity with the 21700, while physically it is not that much larger than 18650, so that’s definitely something. But, a 21700 is also about 50% more expensive than an 18650, so it’s a wash. But if you need more capacity at the expense of slightly larger size, then 21700 gives it to you.

Time will tell what advancements will be made to the 21700 cells in the future.

21700: It’s like 40% more size and 40% more capacity, so not any better density than an 18650.
26650s are lower density but better price per wh.

Also from what I’ve look up quickly, 14500 cells are about 3wh at best, just like eneloop pros.
Seems like they have trouble delivering high currents, while nimh cells still keep most of their capacity at higher currents, and can do 10A no problem.

So yeah it definitely seems like an eneloop AA would be a better choice than 14500, only problem is that LEDs have a higher vf so a boost driver is 100% required adding inefficiency.
This can be solved by using multiple AA or AAA cells rather than a single one and a boost driver, like led lenser does. Their lights use 3-4 cells.

It never was

Meh. Does anyone else feel like notawackjob is getting other people to do his homework for him?

Well I mean he kinda is right when comparing eneloops to current 14500 batteries.

Well I don’t have homework that needs to get done so I don’t need others to do it for me.

:laughing:

Eneloops are miraculous. The pinnacle of a technology. They are a practically immutable store of power. To think that you can charge a battery today and set it on the shelf for 10 years and it will still have 70% charge, and would presumably charge back up to near full capacity and still provide hundreds or thousands of charge cycles… Incredible. And it’s pretty safe, provides some serious amps, and has a relatively flat discharge curve. Definitely underrated.

It’s 1 year to 80%, not 10 years.
Also lithium batteries also provide hundreds or thousands of charge cycles depending on the chemistry.

Sanyo packaging now claims 70% of charge after 10 years and 2100 cycles life. (edited previous post to correct) Modern lithiums aside from lifepo4 tend to spec 300-500 charge cycles to 4.2v, but also in question is their shelf life. They used to degrade in both capacity and cycle count over time. Not sure if this has improved much in recent years. LifePo4 is a closer comparison though.

NCM batteries can do 2k cycles.
LCO can do 500-1k cycles.
LTO can do 20-40k cycles.
I think you’re not very familiar with all the different types of lithium cells that exist.

IIRC, I think the lithium-ion cycles are “full cycles”. That is, charge to 4.2v, and discharge to something like 2.75v. The Eneloop cycles are partial cycles. If you full-cycle Eneloops, I think the actual number is closer to lithium-ion. And if you only charge lithium-ion to 4.1v, I think they may even have an advantage in cycles.

Shelf life is a different matter, though. Lithium-ion does seem to degrade faster than the regular Eneloops. Lithium-ion also degrades very quickly if you leave them at full charge, whereas Eneloops seem to do fine at full charge or any charge level. You can’t leave lithium-ion discharged very long, either. And, there’s the whole safety thing, even though I think it’s over-blown for lithium-ion.

NiMH got a bad rap because they really did kind of suck back in the 90’s. And the really bad NiCad cells of the 80’s didn’t help their rep either: even though it was a different chemistry, they still “looked the same”.

Eneloops changed all that, but the public never really accepted them. Alkaleak advertising brainwashed the public to only really consider Duracell and Energizer alkalines.

Now, everything is built-in lipo packs. Disposable tech gadgets means that batteries only have to last a couple of years.