Martin,

That turns out to be a pretty good idea (I reserve 3.0v CR123 batteries as an exception - the applications are too good).

I went on the Energizer website tonight to get some data - I looked at common Energizer alkaline cells from AAAA to D and Lithium AA and AAA. Using their data for ampacity, dimensions, and mass, I did a little quick spreadsheet analysis (PM for spreadsheet if you want it - but I don't log on every day).

I realize that mAh is not power, but since all of these are 1.5 volt nominal (as opposed to a 3.0v CR123), mAh is the variable to measure when looking at total power available from a cell, so I use the term "power" in that context:

Looking at power/volume they rank this way:

1 e95 D 363 mAh/cc
2 L91 AA 360 mAh/cc
3 e91 AA 342 mAh/cc
4 L92 AAA 325 mAh/cc
4 e92 AAA 325 mAh/cc
5 e93 C 310 mAh/cc
6 e90 N 293 mAh/cc
7 e96 AAAA 272 mAh/cc

Looking at power/gram they rank this way:

1 L91 AA 207 mAh/g
2 L92 AAA 164 mAh/g
3 e95 D 144 mAh/g
4 e93 C 126 mAh/g
5 e91 AA 124 mAh/g
6 e90 N 111 mAh/g
7 e92 AAA 109 mAh/g
8 e96 AAAA 96 mAh/g

Quick conclusion: Stick to D cells and AA cells because they are very equivalent in power to weight or power to volume, with the Lithium cells having an obvious power to weight advantage. The lithium AAA is right in there as well, but it's starting to drop behind compared to the others (again, weight advantage exists).


I know that C cell bodies with D cell heads have been a darling of some, but the available energy from C cells doesn't really justify it; 3 AA cells basically "equal" a C cell for volume and capacity and 3 lithium AA cells weigh only 2/3 of an alkaline C cell.

AAA makes most sense in Lithium and is so-so in alkaline.

I was disappointed in the C cell numbers - I figured they would do better than that. but they have less than 1/2 the ampacity of a D cell. As for me - a few AAA for things like my ARC-P s and the rest is either AA or D (OK - I REALLY like the CR123 stuff we have - they are overall about the same as Lithium AA when you factor in the 3.0v)

So sticking to just AA, especially lithiums, is not a bad idea. I have not done the cost comparison, but I suspect that will strongly favor alkaline D cells, which makes them not a bad idea for applications where total weight/bulk is not as critical.

Digest this for yourself; HTH.

Tom