# Do D batteries last longer than AAA batteries?

**URL:** <https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978>\
**Category:** Factual Questions\
**Created:** [May 13, 2003, 4:16pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978 "2003-05-13T16:16:25Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![KidCharlemagne](https://avatars.discourse-cdn.com/v4/letter/k/ed8c4c/32.png) [@KidCharlemagne](https://boards.straightdope.com/u/KidCharlemagne)\
**Post date:** [May 13, 2003, 4:16pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978/1 "2003-05-13T16:16:25Z")

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Since there is more room to fit the reacting chemicals in a D battery, do they last longer or do they both have the same amount of materiel?

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**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\
**Post date:** [May 13, 2003, 4:41pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978/2 "2003-05-13T16:41:05Z")

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The glib answer is yes, D batteries keep going, and going…

Batteries are generally rated for capacity in terms of amp-hours. This indicates the amount of charge the battery is capable of holding. For example, a 5 amp-hour battery being used in a 1 amp circuit will be drained in 5 hours. There are some real world considerations that make that time longer but that’s the general idea.

Since there is more room, as you put it, in a D cell there is a great deal more capacity. D cells have about six times the storage of a AA cell.

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**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\
**Post date:** [May 13, 2003, 4:41pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978/3 "2003-05-13T16:41:39Z")

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How long any cell lasts depends on the load it’s connected to. Batteries are rated for their current delivering capacity over time, or “amp hours”. D cells have less bulk (internal) resistance & can provide larger bursts of instantaneous current than C, AA or AAA cells can. A car battery can deliver 800-1000 amps of instantaneous current, but only for about 30 seconds.

[Battery Data](http://www.techlib.com/reference/batteries.html)

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<div class="post-metadata">

**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\
**Post date:** [May 13, 2003, 4:50pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978/4 "2003-05-13T16:50:46Z")

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And considering the OP, I should have said a D cell provides about twelve times the capacity of a AAA cell.

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**Author:** ![Rocketeer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rocketeer/32/4437_2.png) [@Rocketeer](https://boards.straightdope.com/u/Rocketeer)\
**Post date:** [May 13, 2003, 8:00pm UTC](https://boards.straightdope.com/t/do-d-batteries-last-longer-than-aaa-batteries/174978/5 "2003-05-13T20:00:10Z")

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I remember reading a battery comparison test in Consumer Reports a while ago. The Sears D-cell was in reality a AA, built up with padding until it was D-sized. Seemed a little dishonest to me.