Saturday, December 23, 2017

Comparing AA batteries vs AAA batteries

Energizer E92 AAA battery.  Nominally 1200 mAh at low energy draw or 104 mAh per gram.  Source
A simple AAA battery has five times the energy as the CR2032 "coin" battery powering my Red Dot scope.

Energizer E91 AA battery.  Nominally 3000 mAh at low energy draw or 130 mAh per gram...approximately 25% more energy per unit mass as the AAA battery.  Source
A simple AA battery has twelve times as much energy as the CR2032 in my Red Dot scope in is infinitely easier to find out in the wild.

The mass efficiency of the AA improves even more vs the AAA if the device(s) require a battery carrier to hold three AAA.  Two AA batteries have 65% more energy than three AA batteries and only weigh 17% more than three AAAs in a carrier.

The advantage to longer life is immeasurable.  There is just that much less opportunity to find yourself in the ditch.  There is much comfort to be had when your light works in the dark.

The secondary advantage is that the service life of a AA battery has less "sag" at higher power draws than the AAA battery.  For example, the service life of an AA battery at 250mA is 6.5% as long as it would be when the amp draw is 25mA.  The service life of an AAA battery at 250mA is 5.7% as long as it would be when the amp draw is 25mA.  That is on top of the AAA's shorter service life even at the slower power draws.


  1. I standardized on AA batteries for all my flashlights, lanterns, etc. it's pretty easy to also find solar AA battery chargers. Also not hard to set up a charging station using a lacrosse type 12v battery charger, powered by a 35Ah 12v battery, which in turn can be maintained by a 60w solar panel and a fairly cheap solar controller. Tim

  2. Thanks for this. It reaffirms my desire to have as many of my devices AA as I possibly can. For a device to use another type it'd have to be for a good reason

    I have three torches (yeah I know... I love my torches) that take 18650 batteries, and two that use AA. I really *should* get a hussling with getting a couple of sweet spot AA torches.

  3. Serious question - what about Aimpoints claim of 50,000 hours of battery life? They say you don't turn it off, just put it in the safe with it still running. If true that'd be awesome. Just replace the battery every 2-3 years giving yourself 2-3 years buffer.


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