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Ode to the AA Battery

jeffgeerling.com

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Re: Ode to the AA Battery

#151

Post by jdietrich »

js2 wrote: post #38
aftbit wrote: post #32

Earlier quoted context omitted.

No, there's basically no reason you'd ever want an alkaline battery except cost. For your use case of long-term storage or a rarely used flashlight (e.g. in a car emergency kit), you'd want a Li/FeS2 as the parent poster recommended, also called just a "Lithium" primary (i.e. non-rechargable) cell. They have a longer shelf life, don't leak, hold more energy, can provide a higher discharge current, work over a wider t…

Main disadvantage is cost. Looking on Amazon, it's $1.61/ea AA lithium vs $0.62/ea akalaline. That's Energizer vs Energizer. Amazon Basics AA alkaline are $0.32/ea. (Unlike alkaline, knock-off lithium aren't much cheaper than Energizer.)

If I had a dollar for every device that I've seen ruined by leaking alkaline cells, I could buy a palletload of lithium cells.

Re: Ode to the AA Battery

#152

Post by sowbug »

Pxtl wrote: post #100
sowbug wrote: post #85

Earlier quoted context omitted.

I love the 14500 except for its footgun shape. 6 x 14500 is at least 21 volts, which won't play nice with a device that wanted 9 volts. I used to try to keep the 14500s far away from the AAs, but there's no stopping a kid in a hurry who wants to play with a toy or musical instrument.

I've taken the approach of electrical-taping my USB-chargeable 14500s each to a dummy-battery, since the things I put them in have 2 adjacent slots for series AAs. The voltage is still high (3.somethingV instead of 3V) but they seem to work.

That's smart. It's not perfect, as you say, but at least it's trying to play nicely with the other kids.

Re: Ode to the AA Battery

#153

Post by headPoet »

I have a head-torch with a pretty good compromise. The bay either accepts the proprietary battery, or three AAA batteries. The supplied lithium battery lasts longer than the AAA, but it's nice knowing the device will outlive the battery

Re: Ode to the AA Battery

#154

Post by pimeys »

jdietrich wrote: post #149
pimeys wrote: post #142

Earlier quoted context omitted.

There is one very good reason: the discharge curve. An alcaline battery loses voltage when it discharges, the lithium ones discharge with the max voltage until they suddenly stop working. This is a reason insulin pumps require specifically high quality alkaline and lithium is considered a risk.

Lithium primary cells have a shallower discharge curve than alkaline, but not completely flat; measuring state-of-charge is essentially trivial for any competent design engineer. Medtronic specifically recommend FR6 lithium cells in their insulin pumps. https://data.energizer.com/pdfs/l91.pdf https://www.medtronicdiabetes.com/sites/default/files/librar...

While the Medtronic pump has a setting to toggle between "Alkaline" and "Lithium" to adjust how it reads the battery percentage, the Dana i is primarily calibrated for Alkaline (LR03).

So your mileage may vary...

Re: Ode to the AA Battery

#155

Post by BeetleB »

dragontamer wrote: post #148
BeetleB wrote: post #138

Earlier quoted context omitted.

I think what he is referring to is this: If one battery is 50%, and the other at 70%, and you put both in, one will end up at 80% and the other at 100%. When one is full, those cheap chargers stop charging the pair.

That's not how it works at all. When one is 80% and the other is 100%, the full one enters a state of over charge, reaching 105% or even 110% charge. This is safe. The H2 reaction then rapidly speeds up, leaking energy in the form of heat. The full battery heats up from overcharge but is otherwise safe. You end up with both batteries at 100% and maybe 110%, and a day or two later the 110% overcharge settles down to 1…

I suppose there are lots of different chargers. The one I had made both charging lights turn off when one turned green. Maybe it was overcharging but still showing as red till both were charged?

Re: Ode to the AA Battery

#156

Post by amelius »

dragontamer wrote: post #148
BeetleB wrote: post #138

Earlier quoted context omitted.

I think what he is referring to is this: If one battery is 50%, and the other at 70%, and you put both in, one will end up at 80% and the other at 100%. When one is full, those cheap chargers stop charging the pair.

That's not how it works at all. When one is 80% and the other is 100%, the full one enters a state of over charge, reaching 105% or even 110% charge. This is safe. The H2 reaction then rapidly speeds up, leaking energy in the form of heat. The full battery heats up from overcharge but is otherwise safe. You end up with both batteries at 100% and maybe 110%, and a day or two later the 110% overcharge settles down to 1…

Ok, but do you agree that in this day and age of cheap electronics, it is really not worth it to even consider all this and it is better to just make a charger that doesn't overcharge and doesn't come with extra instructions?

Re: Ode to the AA Battery

#157

Post by amelius »

dragontamer wrote: post #123
D13Fd wrote: post #75

Earlier quoted context omitted.

I'm not sure that's true in practice. Chargers are often shared in a household and you may not have control over people putting things back on the charger. My preference is to have something that charges more quickly, rather than a bunch of spare batteries. Plus if you leave batteries on the overcharge-style charger for long periods of time, I'm pretty sure they just dissipate the extra charge as heat, and that charg…

Don't leave them in the charger! You precharge and then store for a year+. Modern NiMHs only need topping off once per year or less. So you have two piles. Good charged NiMHs and uncharged depleted NiMHs. While(uncharged.size() >= 2) put them in charger. Then once per year, do a refresh charge on all the NiMHs. Easy-peasy.

So now you have two piles, you come back after a year and then have to figure out which is which. All of this because someone wanted to save a few cents on the implementation of a charger.

Re: Ode to the AA Battery

#158

Post by bxparks »

bigstrat2003 wrote: post #129
bxparks wrote: post #122

Earlier quoted context omitted.

Great in theory. In practice, the Duracell alkaline battery will leak caustic fluids inside the remote control and destroy it, and you will have to mortgage your house to buy a replacement on eBay, if it's even available. (I pick on Duracell because they are the worst. They leak if you look at them wrong, when they are brand new, inside the original packaging, before their "expiration date". But all alkalines are bad…

I have never, in my 40 years of life, had an alkaline battery leak and destroy something. I'm aware that it can happen, but in practice it doesn't happen very often.

I don't know what to tell you. I'm older than you. I've seen it happen 20-30 times in my life. I've seen batteries leak in flashlights, clock radios (the backup battery), wall clocks, calculators, cameras, remote controls, thermostats, wireless mouse, and so on.

A few years ago, I had an unopened pack of 8xAA Duracell alkalines. They had expiration dates on them, and had 2-3 years left. Two of the batteries were leaking in the pack.

Over the past 15 years, I have gradually migrated almost everything to NiMH. I don't see leaking batteries anymore in my house. But go to a thrift store, e.g. Goodwill, and open up the battery compartments of things. Many of them will have been destroyed by the leaking batteries.

Re: Ode to the AA Battery

#159

Post by js2 »

Dylan16807 wrote: post #91
js2 wrote: post #38

Earlier quoted context omitted.

Main disadvantage is cost. Looking on Amazon, it's $1.61/ea AA lithium vs $0.62/ea akalaline. That's Energizer vs Energizer. Amazon Basics AA alkaline are $0.32/ea. (Unlike alkaline, knock-off lithium aren't much cheaper than Energizer.)

Well how many batteries do you need as long term storage for emergency use? $10 worth? Everything else use rechargables for a dollar-ish plus charger cost.

I actually can't think of anything besides smoke detectors that I'd use these for, of which my house has 10 or so. Not having to replace those yearly would be worth it. I use Eneloop NiMH or Li-ion rechargeables just about everywhere else.

Re: Ode to the AA Battery

#160

Post by dragontamer »

amelius wrote: post #157
dragontamer wrote: post #123

Earlier quoted context omitted.

Don't leave them in the charger! You precharge and then store for a year+. Modern NiMHs only need topping off once per year or less. So you have two piles. Good charged NiMHs and uncharged depleted NiMHs. While(uncharged.size() >= 2) put them in charger. Then once per year, do a refresh charge on all the NiMHs. Easy-peasy.

So now you have two piles, you come back after a year and then have to figure out which is which. All of this because someone wanted to save a few cents on the implementation of a charger.

The pile with 0 or 1 batteries in it is the one of partially charged batteries.

The pile with 2 or more batteries is the full set of fresh batteries.

Alternatively, buy a Battery Daddy and put +side up when it's charged, and -side up when it's uncharged.

Like the problems you are talking about really aren't that hard to deal with.

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