what batteries do smoke detectors use

Smoke detectors usually use a 9V battery , AA batteries , or a sealed lithium battery that can last up to 10 years. Older models often use 9V, while many newer alarms use two or three AA batteries or built- in sealed batteries.

Quick answer

• Older smoke detectors: usually 9V.

• Newer smoke detectors: often 2 or 3 AA batteries.

• Modern sealed units: may use a 10-year lithium battery that is not meant to be replaced.

Best practice

Check the label on the back of the alarm or the user manual, because the exact battery type depends on the model.

Safety tip

If your alarm is chirping, it may need a battery change, but it can also mean the unit needs cleaning, testing, or replacement.