I've got some very good 18650 Panasonics - 3Ah, but there seems to be nothing worth getting at the 14500 (AA) size. I thought LiIon was meant to hold more power per volume, which is certainly true of the 18650s, about double an NiMH. But 14500s are all 850mAh (the ones claiming higher are Chinese fakes and aren't higher). So you don't actually get more power out of an AA sized LiIon than NiMH. Can they not make LiIon cells that small very well?
I purchased some torches with 14500s claimed to be 2400mAh which I didn't believe. I doubt that they were even close to 850/900mAh as fully charged they didn't last long in the torch. Replacement 900mAh batteries lasted much longer.
Including VAT :-)
No idea about VAT. VAT is not a simple tax as stated by the government when they introduced it on April Fools day.
Presumably not. If you look up big clives teardowns, they are basically rolled up and stuffed into a round cylinder and that gets harder with the smaller ones.
Panasonic don't even make the AA versions.
I guess not, since they tend not to. I'd imagine it has to do with space for the electrolyte and a thick enough conductor not to get too hot and get damaged. I'm sure somebody will find a way though as its a popular size. Is there any better life span or abuse olerance in one over the other? Brian
Why was the AA LiIon size ever invented if it's no good? I've only ever come across LiIon intended products (like torches) that take the larger 18650 size. I only tried the little ones as NiMH replacements. As far as I know, the only advantage to LiIon over NiMH is the increased capacity, and you don't get that with the smaller size.
They are far better at not self discharging
NiMh if left a few months flatten and destroy themselves
Li-Ion is good for a year or more
That's no longer true, since about 10 years ago when Uniross came out with Hybrio, and other manufacturers with similar products. Basically they're just better made NiMH. They don't significantly self discharge, in fact when you buy them they come already charged. Myself I have AA NiMH which I've left on a shelf for 2 years and they still measure as pretty much full.
Piss of with your trolling Hucker.
Well thats news to me and welcome news at that.
Hated NiMh for that exact reason
It was a genuine question. Fuck you.
Funny, I never noticed much drain on the original NiMH (probably lost about 25% in 3 months). NiCad, yes, they were appalling.
The problem is cylindrical batteries are based on a roll of cathode, anode and separator, all tightly rolled up.
The capacity of the battery is proportional to the area of the roll, which is proportional to the length of the unrolled material. The length you can fit in a cylinder is roughly proportional to r^2.
The cell wall thickness is about 0.2mm, which makes an 18650 have 17.6mm for the roll and a 14500 have 14.1mm. By r^2, an 18650 would have 1.56 times the capacity of a hypothetical 14650. But it's a 14500, which means an
18650 can fit 2.03x as much roll area. That would mean about 1500mAh in a 14500. The rest I suspect is overheads, and not trying so hard (much higher demand for high power density in a larger form factor).Also, don't forget lithium batteries are 3.7V nominal compared with 1.2V for NiMH. So you get 3x the Wh.
Theo
Is your F key not working to god?
I see, that explains why Panasonic (the only make I've found that actually has the capacity they state on the label) don't even bother making them.
Yes, but the AA size LiIon has 1/3 of the Ah, so the Wh is identical.
Mine don't, and I still have loads of them from the pre-eneloop era. Since all eneloop did was to improve the purity of the chemicals, perhaps there were already non-self discharging batteries around before then.
I've got ones from before eneloop came out which I charge after they run out, then leave them in a box. They typically stay in there for a few months, then are used just fine in torches, cameras, all sorts. I've in fact never known an NiMH discharge by itself unless it's very old and has been used a lot, by which time it's usually at the leaking stage anyway.
Steven Watkins wrote
Because its one of the most common battery sizes.
All of my torches which take those also have a plastic frame that takes AAs instead. I only use the 18650s. I do have some torches that go on your head that take AA cells and not 18650.
His god ignores him for some reason.
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