Which Batteries for Smoke Detectors? Why These 3 Batteries for Smoke Detectors

Statistics from the National Fire Protection Association confirm that three out of five fire deaths result from homes with no smoke or dysfunctional smoke alarms. A functional smoke alarm is necessary for you and your loved ones. One way of ensuring this safety is by installing functional batteries in your smoke detector. But first, Which Batteries for Smoke Detectors? 

Which Batteries for Smoke Detectors?
Image of Smoke Detectors Batteries

Back in the day, 9v was the go-to battery for many homeowners. However, the progressive modern world embraces two or three AAs as batteries.

Most people prefer AA batteries for their smoke detectors because they have about three times as much energy as that 9V.

While you can use either of the batteries, checking them and replacing them every six months is crucial for your home’s safety.

Some states have passed a safety law for using the 10-year sealed battery smoke alarm. While this is not a requirement for every state, it is advisable to use this battery. 

The AAs and 9Vs batteries are just as good; however, you will need to replace them after every six months constantly.

This feature disadvantages them, giving the 10-year battery smoke detector an upper hand over them. With the latter, you will no longer have to worry about constant battery replacement.

Are All Smoke Detectors Using the Same Battery?

Smoke alarms use different batteries depending on the year of manufacture. However, most smoke alarms use AA cylinder shape batteries of 9V rectangular-shaped batteries. It is easy to identify the type of battery you use as they are often on a conspicuous display somewhere on the battery.

Here are some of the 9-volt batteries you are likely to find in the market for your smoke detector:


This is considered one of the best 9v batteries for your smoke detector. It is a multipurpose battery that you can use on other applications like microphones, guitar pedals, in-ear monitors, radios, security backup systems, and many more.

The energizer industrial battery has a different packaging from what you’ll find at the local store. Unlike the local ones that come in blister packaging, the industrial ones come in cardboard boxes.

Besides, they are also a cheaper option. They are also as powerful as the energizers you’ll find at your favorite market store.


We consider this as the original smoke detector’s battery. It is relatively cheap and cost-effective, especially when bought in bulk.

However, this battery is less durable than you expect. You will likely replace it frequently as it doesn’t have a long shelf-life. 

This battery is an excellent option for a homeowner who is comfortable replacing their smoke alarm’s battery as often as possible.


This battery has the highest quality you’ll find in the market. It is also the most expensive of all batteries available.

They are super tough and have incredible longevity. While they are commonly used in medical devices, they work excellently in high-tech alarm systems. Because of its high durability will work best for alarms located at hard-to-reach places like the ceiling.

Changing the LA522 energizer is a hassle, but the excellent service it will offer will blind any shortcomings it has.

Use other-volt batteries on smoke detectors located at more accessible spots, but use the advanced lithium battery for those in complex locations as they will last you longer.

While it is said to have a 10-year shelf life, we recommend changing it in about 6-7 years. Even more important, we recommend changing your batteries as frequently as your budget can accommodate.

Takeaway: Most smoke detectors either use AA cylinder-shaped batteries or 9v rectangular-shaped. If figuring this out challenges you, it’d be best to contact service providers, especially if your alarms are in those hard-to-reach areas.

How Do I Replace the Battery in My Smoke Detector?

Replacing your smoke detector’s batteries is a crucial maintenance measure. Anytime you hear your device chirping, it is primarily an alert that your batteries are about to die and need to get replaced as soon as possible.

Homeowners are encouraged to replace their smoke alarms twice a year: once when switching to daylight savings time and once when switching back to daylight standard time.

How you change your smoke detectors’ batteries depends on the type you are using.

Quick tip: smoke detectors are of two types; battery-operated and hardwired. Battery-operated ones are exclusively powered up by batteries, while hardwired ones use electricity and backup batteries as their source of power.

If your device has a tamper-resist pin, you must remove it by locking it. Alternatively, if the device has a tamper-resist locking tab, push it open using a screwdriver, twist the alarm then remove it from the bracket.

  •  Described below is how you can change your smoke detector’s batteries:
  • Before replacing the batteries, you must detach your smoke detector from the mounting plate. To do this, twist your alarm in an anti-clockwise direction. (Access the device using a ladder or a chair for safety).

The twisting should release your device, but the mounting plate will remain on the ceiling or the wall.

  • If the alarm is battery operated, replace the batteries as directed by the smoke detector instructions. The general rule is to ensure that the battery’s connectors (+ and -) match with metal plates inside the battery compartment.
  • Once you have installed the battery, close the compartment door or cover.
  • Place the smoke detector back into the mounting bracket and slightly twist it clockwise. Your smoke detector will have engaged by now.
  • Test if your detector is back to normal by pressing and holding the test button. If it produces a loud beep, it will be functioning. If it fails to sound, you must reopen the battery cover and confirm that the batteries are lined up correctly.

Replacing A Hardwired Smoke Detector with a Backup Battery.

A hardwired smoke detector mainly derives its power from the household power source. The backup batteries are usually a “backup” plan in case of a power outage. Here is how to replace its batteries:

  • Before any step, always ensure that you have turned off the electrical service panel. Turn off the household power circuit that supplies power to the smoke detector, Do this by switching off the correct circuit breaker. ( Switching power off is a safety measure to protect you from electrical shock when handling electric wires).
  • Access the detector using a ladder or a chair.
  • Detach the smoke detector from the mounting base by turning it in a counter-clockwise direction. If you notice it is not engaging, chances are it is tamper-resistant on the mounting bracket. Push the locking pin into the unit to disengage it. Other units are different, so you may need to pull the pin out from between the base and the detector.
  • Avoid immediately pulling off the smoke detector because it is connected to a wiring harness. Instead, tilt the device to the side and identify the wire connecting it to the unit. Once you see it, unplug the wire from your smoke detector or mounting base.
  • Open the battery cover on your device, usually located at the back or side of the unit. The negative (-) on the negative mark and the positive (+) on the positive mark. Replace your batteries by correctly matching the terminals.
  • Close the battery cover and reconnect the wiring harness to the unit’s base. Now turn the device clockwise to engage it on the base.
  • Go back to the electrical panel and turn the circuit breaker back on.
  • Test your device’s functionality by pressing and holding the test button. Expect to hear a loud beep as a sign that your device has restored normalcy.

Note: The battery replacement procedures also vary depending on the models. Some models have rear-loading batteries, while others have front-loading batteries.

Also, a missing or poorly installed battery will prevent the battery compartment from closing, which may further prevent your alarm from working effectively.

General Tips for Replacing Most Smoke Detector Batteries.

  • Red lever. The red lever is referred to as a battery reminder finger. Empty the battery compartment, press the finger downward, then press the battery on top. It would help if you also replaced the door.
  • In the presence of a ribbon: Drape the ribbon across the empty compartment of the battery, then replace the battery. Do this to ease the battery extraction process when it’s time to replace it again. Once done, tack the ribbon back into the compartment and replace the battery.
  • For devices with a front load door. Usually, the door is located on the bottom or the side of the detector. This feature saves you from the hassle of taking the detector from its mounting bracket to replace the battery. Pry the door with a butter knife (your fingernail should also work just as fine). For some doors, you will have to slide them to the side before they swing open.
  • When there’s a side door, pry the door open and push it to its entire length. Please close the door by sliding it back into position. Examine the negative and positive marks on the detector and match the batteries accordingly.

Caution!! Do not replace the batteries if they are corroded. Instead, get rid of the whole alarm system and replace it with a new one.

How to Replace Battery In a Smoke Detector:

Can You Use AA Lithium Batteries in Smoke Detectors?

Back in the day, alkaline batteries were the go-to options for smoke detectors. However, starting in 2014, homeowners have been going for either two or three AAs lithium batteries.

The difference between lithium and alkaline batteries is that they are both made from different materials and constructed differently, reflecting the difference in their performance.

You are advised to use AA-lithium batteries in your smoke detectors as they are an excellent, all-around option for your smoke detector and other electronic devices.

Lithium batteries exceptionally work with hardwired smoke detectors as they will last for years. On the battery operated-alarms, the lithium will last long in ionizing alarms but won’t last as long in photoelectric detectors. Please check the bottom part of your alarm to inform whether it is ionizing or photoelectric. 

Therefore, if you want to use AA lithium or alkaline on your smoke detector, you can choose both. While aa batteries are more costly than lithium, they are also rechargeable, making them a cheaper option Afterall.

AA lithium batteries are more reliable than alkaline-based. The alkaline batteries need constant replacement, making them more susceptible to tampering. Tampering with a battery set can have consequences as dire as an alarm failing to work during a crisis.

However, lithium is sealed, built-in batteries which cannot be easily tampered with. Since it is a legal requirement in some areas to have this type of battery, it protects you from being held liable in case of a fire crisis.

AA lithium batteries are also an excellent option because of their durability. However, while their ‘ultra’ life is expected to last ten years, they would only run for a few years (although longer than alkaline batteries).

The good thing about this life span is that it comes with a warranty, which will allow you to replace it at no cost, should it die before the stipulated period.

Caveat: Consumer reports advise against using lithium batteries in smoke detectors unless used on a strict battery replacement schedule. They cite the battery’s high voltage feature as the reason behind the warning.

Accordingly, the lithium batteries will give you a shorter “low battery” warning as an alert for a replacement. This gives the alkaline battery an upper hand over the AA lithium.

Also, while you can always dispose of your alkaline batteries away in the trash, you cannot do this with lithium as they are not eco-friendly. They have to be recycled at facilities that accept them.

Takeaway: You can use AA lithium batteries on your smoke detector as they are durable and hence safer than alkaline. They are also more pocket friendly. However, this does not rule out alkaline batteries, as they are equally good. 

Regularly check and replace the batteries on your smoke detector for maximum protection against fire eventualities.

 How Long Does a 9V Battery Last in a Smoke Detector?

Regularly replacing your smoke detector’s battery is an excellent way to maintain and keep your loved ones safe. You can only do this if you are well-informed about their durability, so let’s find out! I doubt there is any appliance that has no expiry date.

The 9-volt battery smoke detectors are considered the standard and most popular model. The 9v alkaline batteries will last approximately 12-18 months with good maintenance.

You will require to change these batteries once a year or so. To be safe, always consider replacing the batteries once they hit the 8-year mark.

Long-life batteries

These are batteries powered by lithium. Smoke detectors that use this alarm work differently as you have to o by how long the battery will last rather than how long the unit will. WHY? You can never change the lithium battery. Once your alarm hits the ten-year mark, you must replace the whole unit.

Hardwired detectors

Because they are mostly powered by electricity, you are likely to think that hardwired alarms are permanent fixtures in your home. In a way, they are. However, we recommend strictly following the same rules you’d follow while maintaining other smoke detectors. 

It would be best if you replaced the batteries in a hardwired alarm system once every year, the same way you do with the 9-volt battery models.

Tip: If you are unsure how long your smoke detector will last, test it out! Regardless of the model, you can always press and hold the test button on your smoke detector to ascertain if the device is functioning as expected.

Do this procedure at least once every month for the surety; then, you will be prepared in case of a fire crisis.

You can also ensure that your device lasts longer through other maintenance different from replacing the batteries. For instance, clean your device monthly using a vacuum, and wipe off compressed air to eliminate dirt, dust, and debris.

Also, your smoke detector can start chirping before the one-year mark. This usually indicates that you need to replace the batteries as soon as possible.

Do All Smoke Detectors Need Batteries?

Yes, all smoke detectors need batteries. This includes even hardwired smoke detectors. However, not all smoke detectors can be switched out.

As mentioned earlier, some smoke alarm devices come with 10-year tamper-free batteries. With such features, the battery compartments can hardly be opened.

Do You Have to Reset Smoke Detector After Changing Battery?

You probably replaced your smoke detector’s batteries because they are chirping and have become a nuisance. For some reason, the smoke detector is still chirping even after replacing the battery. You may need to reset the smoke detector to clear the system error manually. This is how to do it:

Resetting hardwired smoke detectors with battery backups.

  • Go to the electrical panel and switch off the primary power source. This is to switch off the electrical current running into your smoke detector and protect you from electrical shocks.
  • Unmount the smoke detector from its mounting bracket. Loosen it by twisting it in the anti-clockwise direction. 
  • The device is also connected to a power cable; disconnect it from the smoke detector.
  • Open the battery cover and remove the batteries. 
  • Press the test button and hold it down for about 15 seconds. You will hear an alarm sound briefly, do not panic. It is a sign that the device is working. The alarm will silence after a few minutes.
  • Reinstall the batteries back in their position and close the battery cover. Carefully reconnect the power cable and put the smoke detector back on its mounting bracket. Slightly twist it in a clockwise direction to tighten it.
  • Go back to the electrical panel you switched off and turn it back on. You will again hear a single chirp which will signify that power has been restored to the unit.

If resetting does not solve your issue, consider troubleshooting for more effective ways to solve it.

Resetting Battery-Powered Smoke Detectors

Battery-operated smoke detectors are less complex than hardwired ones. Resetting them is a walk in the pack. Here is how to do it:

  1. Open the battery cover and remove the batteries from the smoke detector.
  2. Press and hold the “test” button for about 15 seconds. You will hear an alarm sound briefly. The alarm will then go silent.
  3. Reinstall the battery back into the casing and close it. Again, you will hear the smoke detector chirp one time. This is to signify that the battery is connected and that it is functional.

Extra tip: If the detector has a blinking red light, press the ‘test,’ ‘silence,’ or ‘hush’ buttons to reset your smoke detector. 

If your alarm has a keypad, press the “*72” (star, seven two) to reset it with a keypad.

Can You Use Duracell Batteries In Smoke Detectors?

The battery you use in your smoke alarm matters as it determines whether or not you will be safe during a crisis. NFPA reports that three out of five fire death cases are from homes with a dysfunctional smoke alarm. A wrong choice of battery could be one of the causes.

You can use Duracell batteries in your smoke alarm as it would offer you service for a reasonable period. Most times, the Duracell batteries are often compared to energizers.

This comparison will help determine whether you will use Duracell or opt for another competitive brand.

Duracell AA batteries are rechargeable and have a longer battery life. While the energizer brand can last 2-3.5 hours, Duracell can last between 5 to 6.5 hours. 

Duracell is also formulated with power boost ingredients such as AA and AAA alkaline batteries. They contain Duracell’s patented POWER BOOST ingredients, which improve their durability. This will keep your smoke detector functioning for longer.

Duracell has a longer shelf-life. It guarantees you up to 12-year storage. You will not have to worry about your battery leaking or potentially to go bad after storing it for a while.

Finally, while you can use Duracell for your smoke detector, you can also use it for your everyday devices.

How Long Does a 10-Year Battery Last In a Smoke Detector?

The ten-year smoke alarms are those powered by sealed lithium batteries. From its name, these batteries are designed to last for ten years. 

They will offer your home continuous protection for ten years without the need to replace the batteries. However, NFPA recommends replacing all smoke alarms after every ten years to ensure that the devices are functioning as required.

Here are some of the benefits of owning a ten-year sealed battery in your home:

  • It saves you from the hassle of changing batteries every six months. (Life is always busy, the thought of changing batteries can easily escape you). 
  • Always check whenever the alarm chirps, but in this case, it is unlikely that it’s an alert about the battery. Other regular batteries will likely ruin your peace by constantly chirping to warn you that they are about to run out. You will not experience this with the 10-year battery.
  • If an alarm with 10-year battery chirps, you know it is time to change the alarm system. It is usually an indicator that the system has reached its end of life, and you need to replace it.

While it is more expensive than other types of batteries, consider investing in a ten-year battery. It will give you peace of mind knowing that your home and your family have been fully protected for a decade.

This investment is also friendly to your pocket. You will not have to endure the cost of constant replacement of batteries. Besides, the battery pack is also sealed so that no one can tamper with your alarm device.

Should I Use Lithium or Alkaline Batteries In My Smoke Detector?

Using alarms with traditional (alkaline) batteries is fine. They will serve and protect you just as fine with proper maintenance.

However, these batteries need a regular replacement, at least once a year. This means that whenever they are about to run out, you will experience constant chirping, which will demand immediate attention. Lithium batteries are different.

Lithium batteries are recommended and preferred over alkaline ones. This battery will last as long as your alarm lasts (an average of 10 years). Besides, you can also acquire the 9v lithium batteries to upgrade the existing alarm.

While lithium batteries will offer you total protection, always push the test buttons every month. This helps in confirming and ensuring that your alarm is functional.

Final Thoughts

Smoke detectors effectively protect your home and family against any fire risk. They will alert you in the event of a possible fire. However, they need functioning batteries alongside other maintenance practices to do this. So,

Which Batteries for Smoke Detectors?

Smoke detectors usually use the 9Vs and two or three AAs batteries, depending on the year of manufacture.

We hope this article will help you next time you want to replace the batteries in your smoke alarm. If you replace it, and the alarm still chirps, reset the device using the instructions provided in the article.

Let us know in the comments what you think. Best of luck!

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