Why the sloppy tolerances in AA battery diameters?

[geepondy]

I blamed it on the DX lights on the fact that my Eveready 2500mah batteries would not fit in the battery tubes but I am finding they won't fit in a lot of devices I own including my shortwave radio and clock/radio battery backup. Likewise for my Rayovac Hybrids but the Sanyo Enerloops fit fine as well as any alkaline I have tried.

What is the min/max spec'd diameter for these cells (or is there any) and are these fat cells complying with the spec? Sure you can make a higher capacity cell by making it fatter, eventually you can start calling it a C cell.

 

[shadowjk]

I think rechargeable AA are usually bigger than alkaline AA...

 

[TigerhawkT3]

I recently got some portable battery-powered speakers, and the battery tube is incredibly finicky. Alks work, along with D2300s and Sony CycleEnergy (rebadged Eneloops). However, Lenmars, XGs, and ROV Hybrids didn't fit. Seeing as how there was no head to take off so as to push from the other end, it was a chore removing the oversized cells.

So yeah, I hear you. The specified dimensions have got to be followed a little more precisely.

 

[Mr Happy]

As I remember it, the regulation diameter of an AA cell is specified as between 13.5 mm and 14.5 mm. This is unlike most other cells, which have a single nominal diameter and not a range.

If you are unlucky enough to get some cells which push the diameter right out to 14.5 mm and a device which was designed with little room to spare, you could have trouble fitting the cells in the device.

 

[Sub_Umbra]

I recently got some portable battery-powered speakers, and the battery tube is incredibly finicky. Alks work, along with D2300s and Sony CycleEnergy (rebadged Eneloops). However, Lenmars, XGs, and ROV Hybrids didn't fit...

When I read something like that I always wonder if the cells haven't been clumsily rebranded by just shrinking a second skin over them. I don't know.

I've had problems that go as far back as ~23 years (OMG) labeling AA NiCDs with Avery labels -- that small thickness made them not fit in some devices.

There is also the possibillity that this is a manifestation of 'Form Factor Creep'. Competition is so tough to get the most mAH in each companies cells that aside from skins and separators getting thinner, we've also noticed some outside dimensions being pushed to the limit.

A couple years ago the Duracell Coppertop AAA got bigger in a very subtle way -- they changed the radius at the negative end without increasing the diameter or length of the cell. The difference means that Coppertop AAAs will no longer work in some Catseye bike lights without re-bending the light's negative contacts.

Primary or secondary, it's a very competitive world.

 

[geepondy]

Monday, I will take some cells to work and measure them with a caliper.

 

[Burgess]

My ZebraLight H50 headlamp
won't accept 6 of my 24 Duracell 2650 NiMH AA cells.

(all made in Japan, with same date-codes!)


That's 25% of 'em which just plain-ol' won't fit.

Not even CLOSE !

It's not a "i can stuff 'em in, but won't be able to get 'em OUT",

But rather, no way in Hall that you'd EVER get 'em IN !


Now, i'm not sayin' it's a big problem with the ZebraLights . . . .


Just be aware of this fact.

And be sure to test each and every one of 'em,

BEFORE you get into trouble.


If i had a 4-pack of spare AA's in my pocket,
and NONE of them would fit into my ZebraLight,
i'm afraid i might be a bit, errrr, disappointed.

___ :hairpull: ___

_

 

[SilverFox]

Hello Mr Happy,

Do you happen to know if the maximum diameter figure is supposed to include the label?

Tom

 

[greenlight]

My canon takes 4 AA, and I have a couple of cells that get stuck in one of the slots. I made a hook tool to remove them. Without the tool, they are VERY difficult to remove.

 

[Anders]

Standard NiMH batteries have a wide tolerance range.


Length
Width

Rechargable Min Max Min Max
AA-Rechargable 47.3 50.5 13.5 14.5
C-Rechargable 48.5 50.0 24.9 26.2
D-Rechargable 59.5 61.5 32.2 34.2




Dimensions shown are mm


IEC-ANSI standards




The minimum – maximum, length and width for common batteries is fairly wide.
Length
Height

Alkaline Min Max
Min Max
D cell 59.5 61.5
32.3 34.2
C cell 48.5 50
24.9 26.2
AA cell 49.2 50.5
13.5 14.5
AAA cell 43.3 44.5
9.5 10.5
6 volt 23.9 25.2
12 13
9 Volt 46.5 48.5
34.5 26.5


Anders

 

[Mr Happy]

Do you happen to know if the maximum diameter figure is supposed to include the label?

No, I'm afraid I don't know the exact wording of the IEC/ANSI standards.

One would imagine though, that the maximum diameter is supposed to apply to the finished product including label since the purpose of the standards is to define the size of battery holder or enclosure that the battery will fit into.

If the cell is too large, it may not fit (obviously). If the cell is too small, it may not be held securely in place and may fall out when subjected to shock or vibration.

I see also that all cells have a range of dimensions, not just AA cells. For example the diameter of a D cell is supposed to be between 32.3 and 34.2 mm, while an AAA cell is between 9.5 and 10.5 mm.

Here's an interesting reference: http://www.batteryholders.org/battery testing and compliance.shtml