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.
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.
None of the consumer Li-ion cells I have owned have claimed more than 500 cycles life in their datasheets, (aside from lifepo4) but also I don’t trust their specs over time. In my experience they degrade substantially over the years. SoC and DoD play a big part in cycle life, and in the case of li-ion, storage voltage, yea. Batteryuniversity makes a claim that for every reduction of .1V when charging a lithium ion its cycle life doubles. Regardless, Eneloops are an amazing bit of technology and stand up over time.
Had a private message by one of our esteemed regular posters here recently.
Part of the back and forth was my sentiment that Eneloops are a MONUMENTAL bargain. When the Japanese make something really well it’s usually better than anything being made bang for the buck. This is one of those rare very high quality things that we also get cheaply. Costco oft has packaged Eneloop sale deals that are awesome.
I also mentioned that if ever the SHTF people that have lots of Eneloops are probably going to be in many a bartering catbird’s seat. If you can afford it buy a bunch just in case.
As I said, if Eneloop made an 18650 size I’d be all over it. Oh, and a 9volt would be ok with me too. Tenergy is ok but Eneloop is still where it’s happening IMO.
Sure the Vf issues with most LEDs hinder the single NiMH format vs larger lithium but regardless of inefficiencies with boost drivers they still can do remarkably well if you can live with lesser max output run times.
3xAAA flashlights aren’t much thicker than 18650 and don’t really have Vf issues.
Yeah, but they have about a fifth of the amps and a quarter the capacity of an 18650.
apples-oranges
silly argument
they both are useful, no?
one will not replace the other
I don’t know about all this sciencey stuff, but eneloops saved my a$$ for my kids’ flashlights, toys, and game controllers!
Added benefit is that now my kids fully understand the economic and environmental advantages.
They’ve grown up with these batteries, the same batteries, and none have degraded to the point where they need to be recycled.
The one TRULY amazing thing about NiMH/AA/AAA Eneloops is that they’ve never leaked and ruined anything I’ve put them in, abused them in, or neglected to charge them in. Day in and day friggin out. I can’t remember even ONE Eneloop ever failing. And I own a BUNCH. Underrated? Hell yes. And all this without protection circuits, vents, explosions, fires, or finicky charging requirements.
Eneloops over the years have probably saved me at least multi-hundreds of $$$ in not damaging a friggin thing. For that alone I majorly thank Sanyo and their great engineers.
And then they keep constantly improving the product to boot while keeping the price down.
They deserve more dam good hard driving lights and I wish more would build them keeping them in mind in their designs. AA platform is my darling.
Anyway, this is what this whole topic was about. Appreciating something beautifully designed, robustly constructed, and on top of all that, a bargain.
Lithiums are great too btw. Just a different greatness.
PS. Correction: Eneloops do have hydrogen gas vents.
Are Eneloops (or other NiMH rechargeables) advertised in some parts of the world? Because, in North America, I’ve never seen an ad for them at all. Duracell and Energizer must spend a s**t load of money advertising their crap alkaleaks, which is why the consumer buys them like a addict buys crack.
I think Eneloops are overlooked because few consumers know about them. I think Duracell and Energizer like it that way, because Eneloops are the perfect replacement for their wasteful industry.