Alarm System Battery Types

Alarm systems utilise a backup battery that keeps the alarm system on in the event of a power failure. These internal batteries are normally AGM 12v lead acid batteries. Also known as a standby battery.

We have found that most NZ alarm systems use one of 3 main 12v lead acid battery sizes. The most common alarm system battery is the standard 12v 7ahr.

Standard 12v 7ahr Alarm System Battery

Some battery manufacturers produce a 12v 7.2ahr model in the same case size. Although, on paper this represents slightly higher capacity, in the alarm system application this would provide negligible difference. Given that the standard 7ahr batteries are considerably cheaper and much more readily available, we would always recommend the 7ahr version.

All the lead acid battery manufacturers stick to the same form factor (case size) for this battery. This is a dimension of 151mm long by 65mm wide and 94mm high (with allowances of 1-2mm). The standard 12v 7ahr battery used in alarm systems always has the F1 terminals (4.75mm).

Mid-Size 12v 3-3.4ahr Alarm System Battery

The 12v 3.3ahr or 3.4ahr has a smaller form factor. Used in new model compact alarm systems. The 12v 3.3, or sometimes 3.4har lead acid battery, has the standard F1 (4.75mm) terminals and usually measures 133mm long by 67mm wide by 60mm high, with 1-2mm allowance.

Small 12v 1.2ahr or 1.3ahr Alarm System Battery

This is the smallest lead acid battery of the three. Typically housed in siren units that are attached to the home exterior. The 12v 1.2ahr and 12v 1.3ahr lead acid batteries used for this application are the same size and function the same.

This model has a physical size of 97mm long by 43mm deep and 57mm high.

Replacing Your Alarm System Battery

Although in principle this process is very straight forward, it can vary depending on alarm systems, their age and physical installation location in your home.

Most alarm installer will happily replace your alarm system battery. However, this usually comes at a call out charge plus one hours labour and the cost of the battery. We have heard that this could be as high as $200. While a single alarm system battery is readily available for as low as $30 including on the Mr Positive Website.

Important Safety Warning

Alarm systems are wired to the mains power and depending on their model may have exposed 240v terminals that if touched could cause electric shock and or serious injury.

Some alarm systems have a built-in tamper switch which will sound the full burglar alarm when the alarm system box is opened.

As always, it is extremely important to reference the alarm systems documentation and contact the original manufacturer for extra guidance before you start the process of replacing your alarm system battery.