Will House Alarm Go Off If Battery Dies? Complete Guide

If you’re wondering will house alarm go off if battery dies, the answer is simple.

The house alarms always have a secondary source of power.

In most cases, the primary power source is the AC line, which is connected to the electrical supply of the house and the backup source is the battery.

When both sources are not working, the alarm won’t work as well.

The house alarm will activate even when the backup battery is dead, as long as the AC line continues to provide power. If the backup battery dies during a power outage, the alarm will not activate and will not respond to anything.

Do House Alarms Work Without Power?

Yes, house alarms are made to continue operating even when the AC line is interrupted.

In most cases such interruption comes from a power outage, where the backup battery kicks in, allowing the alarm to continue operating as usual as long as there is juice.

Let’s learn more about what happens when the house alarm backup battery dies…

What Happens When House Alarm Battery Dies?

The house alarms are directly connected to the AC line in the control panel, where the backup battery is located.

When this backup battery dies, your alarm will turn OFF, therefore won’t function until the power is back.

In contrast, when the battery unit is dead, but there is electricity in the AC line, the device would notify you that you’ll need to replace the battery but continue to work.

In case the power goes out and the backup battery is dead, the alarm will not function until the power kicks back in.

• The lifespan of a house alarm battery is from 2 to 5 years!

When the battery of your house alarm starts to die, on your keypad you’ll see a message which would be similar to -“Low Battery” or “Trouble”.

Note: In case you don’t know how to replace the battery scroll down to find the steps.

Will House Alarm Go OFF if Battery Dies?

The short answer is No. Without a secondary power source, the alarm won’t go off.

The house alarm will not activate when the power is out and the backup battery is dead.

The backup battery is not designed to withstand long periods of time and it’s made to cover incidental cases in which the power goes out for a few hours.

Depending on the scope of your alarm and the capacity of the battery, the maximum time they can last is up to 8 hours.

In case the power goes out for more than 8 hours, even with a fully charged battery, the juice will end, hence turning OFF your alarm.

When the power kicks back in, the battery will immediately start to recharge and be ready for outages that might follow.

How Long Does Battery Recharge?

Again, the answer depends on the capacity of your battery. The older a battery is, the faster it will recharge, therefore the shorter it will last.

Speaking of a relatively new alarm with a fresh backup battery, the time it takes to recharge is about 4 interrupted hours.

How To Replace a Dead House Alarm Battery?

The best way to solve the problem with the dying battery of your house alarm is to replace the unit and be confident that your alarm will last at least 8 hours when the power is out.

Here are some simple steps to replace a fast-dying house alarm battery:

1.   Turn OFF The Power!

Make sure that the electrical supply to your house alarm control panel has been turned off before you start interacting with the battery.

You’ll need to stop the AC line power supply which can be done by flipping the room’s switch on the circuit breaker. Beware!

2.   Contact The Control Room

Some house alarms will contact critical parties when the backup battery is disconnected as an alert, therefore sending a team to investigate the trouble.

In case you’ve got a professional monitoring contract, you should reach out to the control monitoring room to notify them.

3.   Open The Control Panel

The control panel of a house security alarm can be opened by a key that users often leave on the top of the control box.

In some cases, you would need to unscrew the cover as well.

4.   Disconnect The Dead Battery

To disconnect the battery you would need to remove both the black and the red wire from the terminals.

Sometimes the wires may require a little twist and wiggling to come loose but soon or later they always unplug.

You can use pliers for safer interaction with the wires.

Alert: To avoid getting shocked, don’t touch the battery terminals and the open end of the wires.

5.   Install The New Battery

That should be the easy part. The only thing to remember is that the printings (text) on the battery should be facing your direction.

From there reconnect the red wire first and then the black wire, making sure that the connection is secured. Again, use pliers for safety.

Note: The new battery should be the same size as the original.

How To Test House Alarm Backup Battery?

There is a way to test the voltage of your house alarm backup battery and easily determine whether it’s time for a change or if the unit will last longer when the power is out.

To perform an accurate test, you’ll need a multimeter that will be able to measure the voltage of the battery.

Turn OFF the AC line again because disconnecting the battery will activate the alarm!

When the power is turned off, follow the steps below:

1. Open the house alarm control panel.
2. Disconnect the red and black wire from the battery.
3. Set your multimeter to Volts (use the Function button)
4. Touch both terminals, respectfully:

• Red multimeter wire to the red terminal
• Black multimeter wire to the black terminal.

A good battery should show around 12-13 V and less than that would mean that the battery will no longer be able to last 8 hours when the power is out.

If you read about 7-9 V, you’ll need to replace the battery as that would translate to less than 4 hours lasting time without power.

Note: House alarm backup battery cost around $30 or even less, based on the model.

House Alarm Beeping After A Power Outage?

The alarm will beep whenever the battery is low or right after a power outage.

• The beeping will continue up to 10 hours, or at least until the power is back.

To stop the beeping that comes after the power has been lost, you’ll need to acknowledge at the keypad that you’re aware that the power is out.

In case you’re not at home, the alarm will continue to beep until the power is restored or when the battery is drained out.

Note: The beeping does not mean that the alarm has been activated.

Quick Recap:

Thus, a house alarm will activate when the battery is dead under the condition that the AC line (secondary power source) is not interrupted. When there is no power and the backup battery of your house alarm is dead, the device will not go off.

Final Thoughts:

Now that we know the answer to the question “will house alarm go off if battery dies?”, you can confidently go on a vacation knowing that your home is secured.

However, in case you need your backup battery to last for longer you’ll need to contact the security company.

Some house alarms can be modified to last longer by increasing the battery capacity or entirely adding a 3rd power source to the system.

Everything depends on your needs and whether the servicing company is ready to fulfill the users’ requirements.