# Smoke detector batteries

**URL:** <https://boards.straightdope.com/t/smoke-detector-batteries/697705>\
**Category:** Factual Questions\
**Created:** [September 6, 2014, 10:35pm UTC](https://boards.straightdope.com/t/smoke-detector-batteries/697705 "2014-09-06T22:35:44Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\
**Post date:** [September 6, 2014, 10:35pm UTC](https://boards.straightdope.com/t/smoke-detector-batteries/697705/1 "2014-09-06T22:35:44Z")

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I’m putting new smoke detectors in, and find it irritating that even with hard wiring they need batteries- can’t the have a big capacitor or a lithium coin cell for backup?

But anyway, smokes are supposed to last 10 years. Are there any batteries that last that long in one of them- we’re talking basically shelf life, correct:

Engergizer Ulimate: 20 year shelf life  
Energizer Advanced: 12 year shelf life  
Regular Alkaline- some say 10 year shelf life.

Whatabout all the Ultimates that my camera doesn’t think are good, but still test into the green on my tester?

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**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\
**Post date:** [September 6, 2014, 11:27pm UTC](https://boards.straightdope.com/t/smoke-detector-batteries/697705/2 "2014-09-06T23:27:45Z")

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There are wired detectors with 10 year lithium batteries.

> **[Kidde 10 Year Worry-Free Smoke Detector, Hardwired with 10 Year Battery...](https://www.homedepot.com/p/Kidde-10-Year-Worry-Free-Smoke-Detector-Hardwired-with-10-Year-Battery-Backup-Smoke-Alarm-21029878/205422307)**
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> The Kidde i12010S is an AC/DC powered, ionization smoke alarm that operates on a 120V power source with sealed-in lithium battery backup. This alarm uses ionization sensing technology. Ionization sensing

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**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\
**Post date:** [September 6, 2014, 11:29pm UTC](https://boards.straightdope.com/t/smoke-detector-batteries/697705/3 "2014-09-06T23:29:55Z")

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I did see those, but they’re single sensor for almost the price of a dual sensor, and I need at least one combination carbon monoxide / photoelectric unit.

Or is having dual sensors a marketing ploy and not that important in real life?

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**Author:** ![Tim\_R.Mortiss](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim_r.mortiss/32/142_2.png) [@Tim\_R.Mortiss](https://boards.straightdope.com/u/Tim_R.Mortiss)\
**Post date:** [September 6, 2014, 11:30pm UTC](https://boards.straightdope.com/t/smoke-detector-batteries/697705/4 "2014-09-06T23:30:44Z")

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There are unwired detectors with ten-year non-replaceable batteries, too. No link, but I’m pretty sure I saw them at Home Depot.