Editing Smoke detector (section)

=== Batteries ===
[[File:Smoke detector alarm battery beep.webm|thumb|Audio of a smoke detector with low power]]
Batteries are used either as sole or as backup power for residential smoke detectors. Mains-operated detectors have disposable or rechargeable batteries as a backup. Purely battery-powered detectors typically use either a 9-volt disposable battery that must be replaced every one to two years, or non-replaceable batteries that last about 10 years, meaning the detector must be replaced when the battery runs low.<ref>{{Cite web |title=What is a 10-Year Sealed Battery Smoke Detector? |url=https://www.firstalert.com/us/en/safetycorner/what-is-a-10-year-smoke-alarm/ |access-date=2025-05-18 |website=www.firstalert.com |language=en}}</ref>

When the battery is exhausted, a battery-only smoke detector becomes inactive; most smoke detectors chirp repeatedly if the battery is low in power. It has been found that battery-powered smoke detectors in many houses have dead batteries. It has been estimated{{When|date=January 2016}} that in the UK, over 30% of smoke alarms have dead or removed batteries. In response public information campaigns have been created to remind people to change smoke detector batteries regularly. In Australia, for example, a public information campaign suggests that smoke alarm batteries should be replaced on [[April Fools' Day]] every year.<ref>{{cite web|last=Beacham|first=Janine|title=Don't be a fool: change alarm batteries|url=http://www.margaretrivermail.com.au/news/local/news/general/dont-be-a-fool-shange-alarm-batteries/2119255.aspx|publisher=Augusta Margaret River Mail|access-date=19 April 2011|archive-url=https://web.archive.org/web/20110403140053/http://www.margaretrivermail.com.au/news/local/news/general/dont-be-a-fool-shange-alarm-batteries/2119255.aspx|archive-date=3 April 2011}}</ref> In regions using [[daylight saving time]], campaigns may suggest that people change their batteries when they change their clocks or on a birthday.

Some mains-powered detectors are fitted with a non-rechargeable [[lithium battery]] for backup with a life of typically ten years. After this, it is recommended that the detector be replaced. User-replaceable disposable [[Nine-volt battery#Lithium 9V/PP3|9-volt lithium batteries]], which last at least twice as long as alkaline batteries, are also available for smoke detectors.

The US National Fire Protection Association (NFPA) recommends that homeowners replace smoke detector batteries at least once per year, or sooner if they start chirping (a signal that the battery is low on power output). Batteries should also be replaced when or if they fail a test, which the NFPA recommends to be carried out at least once per month by pressing the "test" button on the alarm.<ref>{{cite web
 |url         = http://www.nfpa.org/itemDetail.asp?categoryID=1647&itemID=39905&URL=Research%20&%20Reports/Fact%20sheets/Smoke%20alarms/Smoke%20alarm%20safety%20tips&cookie_test=1
 |title       = SMOKE ALARM SAFETY TIPS
 |publisher   = National Fire Protection Association
 |work        = Safety Information.
 |access-date  = 2009-05-17
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20090821222032/http://www.nfpa.org/itemDetail.asp?categoryID=1647&itemID=39905&URL=Research%20&%20Reports%2FFact%20sheets%2FSmoke%20alarms%2FSmoke%20alarm%20safety%20tips&cookie_test=1
 |archive-date = 2009-08-21
}}</ref>