What Type Of Battery You Smoke Detector Needs

Have you been concerned with the type of battery your smoke detectors need? These tools called smoke detectors are important, the batteries are also as important as the smoke detectors themselves, especially for the battery-operated smoke detector that depends solely on its battery to function.

Understanding the Importance of Smoke Detectors

There is much more to smoke detectors than most homeowners think. The truth is, even in brand new buildings and houses, smoke detection systems can be poorly designed and less effective.

Your responsibility as a homeowner or tenant is to ensure that you have adequate smoke detector coverage. Investing in this safety measure will pay back in dividends if you end up experiencing a house fire.

Having smoke detectors placed in various locations around your home allows for fast and effective detection. The smoke detector siren will warn you, day or night, that there is a potential fire, allowing you to quickly check the nature of the problem and hopefully prevent any damage.

When placed in the right location, the smoke alarm can also help firefighters quickly locate the fire in the home, allowing them to better focus their efforts.

Power Supply Options For A Smoke Detector

Now that we have covered the main types of smoke detectors, we need to touch upon different ways of supplying power to the detectors. There are generally two options, both of which work, but one option is definitely a safer and more reliable choice.

  • Battery-Powered Detectors

Most detectors out there are powered by batteries. Since smoke detectors in general don’t use a lot of power, many of these battery-powered models require very little maintenance every year.

However, every battery has a limit and you don’t want to find yourself in a fire with a dead smoke detector. There is nothing inherently wrong with battery-powered smoke detectors, but you have to be absolutely vigilant about replacing spent batteries.

Hard-Wired Smoke Detectors

Generally speaking, this method of supplying power to the entire network of smoke detectors is much more reliable and requires less maintenance.

Best of all, while these detectors still require batteries, batteries are not the primary power source. Rather, batteries act as the emergency power source to ensure you’re still protected in the event of a power outage.

NOTE: Another factor to consider when purchasing any of these detectors is how the alarm is operated. There are smoke and fire detectors as well as carbon monoxide detectors that are battery operated, wired in, or plugged in.

Some detectors have a variety of both batteries operated and wired in/plugged in. The most protective detectors are those that are powered through direct wiring or plugging in but also have a backup battery. The backup battery ensures that even in the event of a power outage, the device will still work.

Most of the detectors that are battery-powered or have a backup battery also come equipped with audible sensors that alert the consumer when the batteries are running low and need to be replaced. This feature allows the detectors to provide maximum protection even without power.

Signs You Need to Replace the Batteries In Your Smoke Detector

You’ll likely notice a high-pitched chirping noise coming from your smoke alarm if the batteries need to be changed. It is best to be proactive and change the batteries in your smoke alarms before that noise occurs.

When you change the batteries in one alarm, make sure you change the batteries in the rest of the alarms in your home as well. A helpful reminder to check your smoke alarms and change the batteries every 6 months is Daylight Saving Time. Check your fire alarms when you change your clocks.

Steps To Replacing the Battery for Non-wired Detectors:

Check the battery type.

Installing the new batteries incorrectly, or using the wrong type, will cause your smoke detector to not function. Always make sure you are using the correct type of battery and installing the batteries correctly to ensure the detector will work.

  • Detectors that use lithium batteries will last for ten years. You generally cannot replace the battery, instead, replace the entire detector after its ten-year life span is expired.
  • Many detectors will make use of a 9v battery. However, some may require different types of batteries.
  • Use high quality, long-lasting batteries. Using rechargeable or low-quality batteries may cause your smoke detectors to fail.

Remove the smoke detector.

You will have to take your smoke detector down from its mounting on the ceiling. If your detector is hard-wired into your house’s power system, you should turn the power off at the fuse box first.

  • The method you use to remove your smoke detector from its mounting will vary depending on which model it is.
  • Most smoke detectors are removed by twisting or sliding the detector away from the mounting.
  • Some detectors will not require you to remove the entire detector. These models require that you remove only the section that covers the internal components and battery.
  • Not all hard-wired smoke detectors will have a backup battery.

Open the battery compartment and install the new battery.

To access the battery, you will have to remove the cover that contains it. Exactly where the battery is located, and how it is secured, will vary from model to model. Generally, once you remove the cover of the detector, you will be able to see where the battery is located without trouble.

  • The location of this cover will vary from model to model, and some may be secured with a screw or other fastening.
  • Most coverings will slide off and away from the smoke detector’s body.
  • Once open, you can remove the old battery or batteries.
  • Make sure you install the new batteries correctly. Check that the negative and positive connections are matching the labels on the smoke detector
  • Close the battery cover.
  • Check your manual for the smoke detector if you are having trouble locating or removing the battery. If you don’t have the physical copy of the manual, you may be able to find it online, at the manufacturer’s website.

Test the batteries.

Before you reinstall the smoke detector, you will want to make sure that the batteries are working properly. Locate and utilize the button on your smoke detector that will test the batteries.

  • The location of the test button will vary.
  • Most test buttons require you to press the button for a few seconds to engage the test.
  • If successful, the alarm will sound.

Double-check if the test fails.

If the alarm doesn’t sound during the test of the batteries, you will need to recheck them. Never reinstall your smoke detector until it passes this battery test and has demonstrated that it is functioning properly.

  • Check to see if the batteries are installed correctly. Make sure the positive and negative terminals are matching the correct terminals in the smoke detector.
  • If the batteries are installed correctly, and the test failed, replace the batteries and try again with new ones.
  • If no new batteries are working, your detector may need replacing. You may want to contact the manufacturer, as they may replace the detector if it is under warranty.
  • Some alarms have an LED-light that will indicate if the alarm is working properly. Generally, a green light indicates that the alarm is working properly, a red light indicates an issue.

Which kind of Battery Do You need?

Look at your owner’s manual for the proper replacement battery. If you’ve lost your owner’s manual, you can probably find one for free online. Normally, smoke alarms require a 9V battery, however, for some models, you’ll need AA or AAA batteries. After you know which kind of batteries you need, buy a high-quality version, like lithium.

  • AA or AAA batteries – most modern smoke alarms run on 2 or 3 of these batteries
  • 9V battery – used in many older smoke alarms
  • Lithium battery – these are built into the unit and can’t be replaced

Manufacturers recommend that you don’t use rechargeable batteries in smoke alarms, as these may not provide the consistent charge needed.

9V vs. AAs Batteries

9V has been the battery of choice for smoke alarms for many years. However, nowadays, it is more common to see two or three AAs. AA batteries have about three times as much energy as a 9V.

When using batteries like these, you must check them consistently and replace your smoke alarm batteries every 6 months. A good reminder is to change them every time you change your clock for daylight savings.


Above all, never remove the battery in your smoke alarm (without immediately replacing it). Resist the urge to remove your smoke alarm battery for use in other items, like your TV remote. And, who hasn’t set off a smoke alarm accidentally while cooking something in the kitchen? Disabling a smoke alarm or removing the battery can be a fatal mistake. If you accidentally set off your smoke alarm, try opening a window, or waiving a towel around the alarm, to help clear the air, but please do not remove the battery because you might forget to put it back in later.