Replacing Alarm System Battery

If you have a home alarm and the alarm system is indicating a battery problem or low battery it’s probably time to replace it.  The backup battery’s job is to keep the alarm system working if power fails.  They are constantly charging and eventually they start to lose their capacity.  Replacing your alarm system battery can be done by the homeowner if you follow some simple guidance.

First you’ll want to check the size and shape of the battery.  Most wired alarm systems have the battery installed in a metal cabinet in the basement or wiring closet.   If you can open the cabinet you will find a rectangular shaped battery and it will have some numbers on it.  These alarm batteries will be 12V and either 4AH, 5AH, 7AH or 8AH in most cases.  The model number is usually a good indication.   For example DSC alarm batteries are often BD412 (12V 4AH) or BD712 (12V 7AH).   When replacing the battery it’s a good idea to stick close to the original rating but it’s OK to change slightly.  Eg. we often recommend ELK-1250 for customers replacing a 4AH battery and ELK-1280 for replacing a 7AH battery.  Why?  Longer run time and bettery quality battery with a longer warranty.

To physically change the battery, first disconnect power to the alarm.  Usually there is a plug-in power supply near by.   Some systems are hardwired – in this case you might throw the breaker feeding power to the alarm.

Next take note which wire goes to the + (positive) and which wire goes to the – (negative) terminal of the battery.  Remove both wires from the battery, put the new battery in its place and reconnect the wires being careful to match the + and – terminals again.

Re-apply power to the alarm system and you’re all set.  You might have to clear the error message on the alarm keypad and it will take up to 24 hours for the battery to be fully charged so don’t panic if the error doesn’t go away right away.

It’s also possible to replace alarm batteries from smaller wireless systems like AlarmForce systems for example.  The ELK-1208J2 is the replacement for these.  In fact Elk is the manufacturer for the batteries in most of these systems.