Updated 02/11/2026
If your alarm is beeping, the most common cause is a backup battery that has reached the end of its life. It can also be a communications or power fault. A beep is the alarm telling you something needs attention, so it is worth finding the cause rather than just silencing it.
This guide explains what the backup battery does, the signs it is failing, and what to do about a beeping alarm.
What the alarm backup battery does
Most alarm panels run on mains power and keep a rechargeable backup battery inside the panel. If the power goes out, the battery keeps the alarm, its sensors and its monitoring connection running until the power comes back. Without a healthy battery, a power cut can switch your alarm off when you need it.
Backup batteries wear out with age. As they get older they hold less charge, until the panel decides the battery is no longer good enough and reports a fault.
Signs your alarm battery is failing
- The keypad beeps, constantly or every so often
- A battery, power or system fault shows on the keypad
- The alarm drops out or resets during a power cut
- Your monitoring company reports low battery signals from your system
- The battery is several years old and has never been replaced
Other reasons an alarm beeps
Not every beep is the battery. A beeping alarm can also point to:
- A power fault, such as the panel losing mains power
- A communications fault, where the alarm can no longer reach its monitoring station. Older alarms that dialled out over a phone line or the retired 3G network are a common example
- A sensor or tamper fault, such as a sensor that has been knocked or a cover that is not closed
Because the beep can mean different things, a technician tests the whole system, finds the actual cause and fixes that.
Can I replace the alarm battery myself?
On some systems a battery swap looks simple, but the battery sits inside the alarm panel, and opening it can trigger a tamper alarm or a monitored response. The new battery also needs to suit the panel. If the alarm is monitored, let your monitoring company know before anyone opens the panel.
A service visit is usually the better option, because the technician tests the panel, sensors, battery, siren and monitoring communications at the same time, so you know the whole system is working.
How often should the battery be checked?
The backup battery should be tested as part of a regular alarm service. A battery that is tested and replaced on a schedule is far less likely to fail during a power cut or start beeping at 2am.
Alarm battery replacement and repairs in Perth
Rest-A-Sured handles alarm repairs and servicing across Perth and regional WA, whether we installed the system or another provider did. You do not need to have bought the alarm from us to book a repair.
- WA owned and locally owned, based in Wangara
- In the security industry since 1998 (28 years)
- WA security licence 09458
- Affiliated with one of the largest independently owned grade 1 monitoring stations in WA
- 2 year warranty on installations
If your alarm is beeping or showing a fault, call 08 9309 9500 (Monday to Friday, 8am to 4pm) and we will get a technician out to find the cause.
Alarm beeping and battery questions
Why is my alarm beeping?
A constant or intermittent beep is almost always a fault warning. The most common cause is a backup battery at the end of its life. It can also signal a power or communications issue.
Will my alarm work in a power cut?
It should, as long as the backup battery is healthy. The battery keeps the alarm and its monitoring connection running until the mains power returns.
Can you replace the battery in an alarm someone else installed?
Yes. Rest-A-Sured repairs and services alarms installed by other providers, and can take over monitoring on most existing alarms.
My alarm used to use a phone line or 3G. Is that why it beeps?
It can be. Alarms that relied on a landline or the retired 3G network may no longer reach their monitoring station. The communications can often be upgraded without replacing the whole system.