# Battery sizes: AAA, AA,... A? **URL:** \ **Category:** Factual Questions\ **Created:** [July 9, 2003, 10:32pm UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335 "2003-07-09T22:32:53Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [July 10, 2003, 12:22am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/21 "2003-07-10T00:22:16Z")
BTW, regarding early radios: There’s a confusion of terminology here. Early radio receivers had “A” and “B” batteries (and sometimes “C”), but this had nothing to do with our modern nomenclature for battery sizes. The “A” battery was a low voltage battery which supplied relatively high current for lighting up the tube filaments. The “B” battery was a higher voltage battery that supplied plate voltage at lower current. Very early radios had a separate “C” battery to supply grid voltage. ---
**Author:** ![Tedster](https://avatars.discourse-cdn.com/v4/letter/t/4491bb/32.png) [@Tedster](https://boards.straightdope.com/u/Tedster)\ **Post date:** [July 10, 2003, 12:26am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/22 "2003-07-10T00:26:46Z")
Back in the days of tube radios, an “A” battery ran the tube filaments, usually in a series string. These were low voltage, high current cells. The high voltage, low current “B” batteries supplied the tube plates. ---
**Author:** ![elmwood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmwood/32/3060_2.png) [@elmwood](https://boards.straightdope.com/u/elmwood)\ **Post date:** [July 10, 2003, 2:29am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/23 "2003-07-10T02:29:31Z")
Whatever happened to nine volt batteries, anyhow? I haven’t bought any devices that use them in over 20 years, and I seldom see them in stores along with other batteries. Why did they fall out of favor? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [July 10, 2003, 2:34am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/24 "2003-07-10T02:34:26Z")
There’s plenty of things that use 9-volt batteries. Every smoke detector I’ve seen on the market these days uses them, for one thing. ---
**Author:** ![Trigonal\_Planar](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Trigonal\_Planar](https://boards.straightdope.com/u/Trigonal_Planar)\ **Post date:** [July 10, 2003, 3:04am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/25 "2003-07-10T03:04:38Z")
Lots of electronic kids toys I see use the 9-volters too. ---
**Author:** ![elmwood](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmwood/32/3060_2.png) [@elmwood](https://boards.straightdope.com/u/elmwood)\ **Post date:** [July 10, 2003, 5:12am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/26 "2003-07-10T05:12:38Z")
Forgot about smoke detectors. Used to be that most pocked-sized devices were powered by nine volt batteries, but now they’re usually powered by two or four AA cells. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [July 10, 2003, 5:58am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/27 "2003-07-10T05:58:00Z")
> [@](#): > > \*Originally posted by kanicbird \* > **It would seem that companies such as duracell and energizer would come up with a rectangular cell over the tubeler AAAA cell to increase energy density…** Rectangular cells tend to be less efficient (less capacity for the same weight and cost) than cylindrical cells. Something to do with the shape of the electrodes and how it’s easier to package them in a cylinder. Many laptop batteries use cylindrical cells these days - SONY uses cylindrical battery packs, and even the rectangular battery pack on my ThinkPad has a curved surface suggesting there are three rows of cylindrical cells inside. By the way, many clock radios still use 9-volt batteries for backup. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [July 10, 2003, 6:40am UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/28 "2003-07-10T06:40:25Z")
> [@](#): > > \*Originally posted by Q.E.D. \* > \*\*That’s not half as bad as the underhandedness of rechargeable NiCd maufacturers. _Consumer Reports_ did an investigation of D-sized cells and found that evey brand they tested, excpet RadiShack, was a C-size cell in a D-size package. The RS D-cell was a the only true D. Whodathunkit? \*\* Well, of course they are! I’m not sure what you see as underhanded about this. NiCad batteries are physically larger than an equivalent regular battery, so to fit into the D cell space in your flashlight or whatever, NiCad’s obviously have to be internally smaller (less charge). And if they didn’t fit, they’d be useless. And you can hardly claim that you were somehow cheated financially, since the NiCad will save you a whole lot of money over its lifetime compared to the regular battery. I suppose you could say that the NiCad runs down faster than the regular alkaline battery; that’s obviously true by definition; so what? I think you’re getting yourself all excited over nothing here. ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [July 10, 2003, 12:47pm UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/29 "2003-07-10T12:47:57Z")
Ask a simple question–get an answer with more depth than you’d expected! ---
**Author:** ![BwanaBob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bwanabob/32/2985_2.png) [@BwanaBob](https://boards.straightdope.com/u/BwanaBob)\ **Post date:** [July 10, 2003, 1:12pm UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/30 "2003-07-10T13:12:26Z")
> [@](#): > > \*Originally posted by [t-bonham@scc.net](mailto:t-bonham@scc.net) \* > \*\*Well, of course they are! I’m not sure what you see as underhanded about this. > > NiCad batteries are physically larger than an equivalent regular battery, so to fit into the D cell space in your flashlight or whatever, NiCad’s obviously have to be internally smaller (less charge). And if they didn’t fit, they’d be useless. > > And you can hardly claim that you were somehow cheated financially, since the NiCad will save you a whole lot of money over its lifetime compared to the regular battery. I suppose you could say that the NiCad runs down faster than the regular alkaline battery; that’s obviously true by definition; so what? > > I think you’re getting yourself all excited over nothing here. \*\* I believe Q.E.D. thinks it’s underhanded because if you see two objects with identical voltage, in this case a C and D cell, one would naturally assume that the larger item would last longer because it contains more of the chemicals inside. In this case (NiCads), I don’t think it’s unreasonable to expect the larger NiCad cell to carry more charge. Therefore one is being cheated if a D cell is just a C with a bigger casing. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [July 10, 2003, 11:44pm UTC](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335/31 "2003-07-10T23:44:13Z")
> [@](#): > > \*Originally posted by BwanaBob \* > \*\*In this case (NiCads), I don’t think it’s unreasonable to expect … \*\* It may not be unreasonable, but it’s just plain mistaken. For the same amount of charge, a NiCad battery occupies more physical space than a regular Alkaline battery; due to the laws of physics. That’s part of the price we pay for the rechargability. To fit both into a standard size (a ‘D’ cell), you will have to accept less charge (amperage) in the rechargable one. * * * What I found more interesting in that Consumers Reports article was that they peeled off the wrappings on all of the batteries, and found manufacturing indicators underneath that seemed to indicate that they all came from 1 of 2 manufacturers. So apparently the dozen or so brands of batteries, that compete so strongly in advertising, all come from the same couple of factories! Thus the Consumers Reports advice: within types (like regular, alkaline, etc.), buy the one that’s cheapest. [Previous page](https://boards.straightdope.com/t/battery-sizes-aaa-aa-a/187335.md?page=1)