How to Change a Smoke Detector Battery?

If you have ever had a smoke detector that chirps like a wild bird during daybreak, you’ll know that one of the main reasons for a smoke detector false alarm is that your smoke alarm battery is running low and needs to be changed. 

If you have never done this before, don’t worry – you don’t need to call in an expert to help you fix that. We’ll teach you how to change your smoke detector battery in just 4 easy steps. 

Do All Smoke Detectors Have Batteries?

Although smoke detectors can be hardwired, nearly all smoke detectors will contain a battery of some sort: being a battery-powered smoke detector, or mains-powered with an emergency battery. 

Whatever the type, as all smoke detector batteries have an average lifespan of approximately six months, you will eventually have to replace your smoke detector battery.

Let’s find out how below.

Step-by-Step Guide to Changing a Smoke Detector Battery

First, you should never ignore a chirping/beeping smoke detector, nor should you ever remove a smoke detector battery (to silence it) without replacing it immediately. A fully-operational smoke detector is an integral fire safety tool adding a layer of protection for your family, home and belongings.

If your home has lithium battery-based smoke detectors, you will be required to replace the whole unit, which usually has an approximate lifespan of ten years.

For the pre-preparation of changing a smoke detector battery, you will need to determine whether the unit is entirely removable from the ceiling in one piece, or, merely the outer shell. Typically, regardless of type, a firm, counterclockwise twist can begin the process.

Step 1: Removing the Cover or Body

You will need to gently-but-firmly pry or unclip the outer shell of the smoke detector from the base, using a partial twisting method. Once you have access to the internals, you will see three parts:

  • The battery (or house voltage power source)
  • Sound horn
  • Sensing chamber

Step 2: Replacing the Battery

You will need to unclip the depleted battery from its housing unit. The majority of smoke detectors will use a 9-volt battery: where possible, replace it with a new 9-volt lithium battery.

Ensure that the male/female connectors are aligned correctly and that the battery is embedded firmly and correctly within the housing unit.

Step 3: Closing the Cover

Here, you will do the opposite of Step 1: closing the cover or replacing the outer shell. Ensure that the body is snapped firmly shut or locked back into its base.

Step 4: Testing the Smoke Detector

Pressing the testing button – found on the surface of the unit – will allow you to ensure that the smoke detector battery is working correctly and functional. When you press the testing button, the smoke detector, if working properly, should emit a chirp or beep.

That’s it – with all the four steps above complete, you now know how to change your smoke detector battery in a matter of minutes. 

Want to learn more? Here’s everything you need to know about smoke detectors, as well as a handy comparison between smoke detectors and heat detectors