Regarding alkaline batteries (AA and AAA) - capacity is a function of weight?

I'm seeing more and more stores selling huge packages (24/32/48) packs of AA and AAA batteries, and usually not a name brand like duracell or energizer.

So it's a crap shoot knowing how many milli-amp hours of capacity these batteries have.

I have a gut feeling that the amount of juice in these things is proportional to weight.

Are there any studies or has anyone tried to correlate the weight (mass) of a brand new AA or AAA battery with how many watt-hours can be had from them?

Reply to
Home!Guy
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I solved all my battery problems with Eneloops and a good charger.

And I've *never* had an Eneloop leak and ruin my expensive toys either.

Reply to
homme de la maison

No idea, but we bought a couple of big packages of Maxells a number of years ago. Every single one corroded and corroded the contacts of the items they were used in. I can't say anything bad enough about these.

I bought a number of precharged Duracell AAs to use in my camera a couple of years ago. Theory has it that they hold 90% of their charge after a year. No. It's almost all gone after a few weeks, only a little better than the normal NiMH batteries. Not happy.

I buy Kirkland alkalines when I run out. Not unhappy.

Reply to
The Real Bev

I have never tried the precharged Duracells, but expect the 90% figure is when stored, not installed in a camera. I think most cameras draw a small amount of current when turned off.

Over the years, I have had many items of equipment ruined due to name-brand alkaline cells leaking. Lately, I have been using Energizer Lithium cells for AA and AAA applications. They are more expensive than alkalines, but Energizer claims they have much more capacity, and I have never heard of one leaking.

Fred

Reply to
Fred McKenzie

I make it a point to not leave batteries installed in things I am not actually using. Mostly, anyway.

Reply to
Pico Rico

Maybe phones do, but I can't see why a camera would need to. And I'm talking about the extra batteries that I keep in appropriate plastic containers in my camera bag. Sometimes I get NO shots from one of these batteries, although I know I last charged them within weeks.

These are the only ones that leaked consistently.

So when the lights go out you have to look for batteries in addition to looking for the flashlight? I finally put a pack of matches in with the bag of candles and I can find the bag of candles in the dark.

Reply to
The Real Bev

Twice I bought noname AA cells in packs of forty at a decent price, and I had no problems with them. I couldn't tell any shorter period of use than others.

They literally were no name, that being the house brand for Loblaws here in Canada.

I try to use nimhs for the heavy duty stuff, but there is still lots that need batteries but actually suffer from rechargeables because those have a lower voltage (and likely don't keep recovering voltage as time goes on). Things like remotes and flashlights (which in reality means I'd like to have them ready when needed, rather than have to search for rechargeables or charge them up before using the flashlight). So it was good to find a cheap source of AAs. Sadly, they dont' seem to have that forty pack anymore. The brand name large packs are of course more expensive.

Michael

Reply to
Michael Black

How long does it take for you to use that many batteries? I'd be worried that the shelf life expires or they leak before I get around to using them.

I've never seen a completely dead battery that crumbles to dust (leaks and corrodes the guts of your device is something different) or can be blown away with a sneeze, not even those tiny coin cells.

The capacity *when new* may be roughly proportional to the weight of the battery (and the active chemicals in it) when new, comparing only those that use the same type of chemical system (e.g. carbon-zinc, alkaline, NiMH, Lithium-ion, Nickel-Cadmium, lead-acid, etc). Don't count the weight of terminals, labels, plastic holders, etc. Rechargeable batteries generally have labels with a milli-amp-hour rating (whether that rating is accurate is another issue.)

So D cells have more ampere-hours than AA cells which have more ampere-hours than AAA cells, provided nobody cheats and fills space inside them with air. (There are some D-cell adapters that hold 3 AAA cells in parallel. Much of the space is plastic and air. You may get the same voltage when fresh but it's going to wear out much faster than a real D with the same chemical system.) Car batteries are large because they need to be to give enough starting energy to crank the engine, especially in cold weather.

This does *NOT* mean that a half-dead battery weighs half of a fresh one. Aren't most types of batteries supposed to be sealed (lead-acid being an exception for some car batteries)?

There is only a limited amount of space in an AA cell, and trying to cram in more after it's full (to get more energy out) isn't going to work. So all AA cells are going to weigh about the same, except for the cheaters who fill part of the space with air.

There is the formula E = mc**2. However, don't count on being able to measure the difference between the weight of a fully-charged battery and a dead one. Even an atomic bomb uses only a tiny fraction of the mass-energy of the active material (plutonium) although you may have trouble finding all the remaining pieces to weigh them.

Reply to
Gordon Burditt

Cameras have settings that are kept in memory, and at least mine loses those settings if you remove the batteries for too long (e.g.

15 seconds). The batteries are used to keep this memory "alive".

I've seen rechargeable batteries that both hold a charge for a few months on the shelf *AND* run down in one week in the camera. Although I really shouldn't leave batteries in the camera that long.

Reply to
Gordon Burditt

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