How to Replace a Battery in a Honeywell Alarm System

Replacing the battery in your Honeywell home security system is a simple task. When the battery gets low, the keypad display will read "BATT," which is your cue to get this chore done.

Replacing Your Keypad Batteries

Step 1

Enter your security code to disarm your alarm system. If your security system is AC-powered, make sure the AC cord is unplugged from its outlet.

Step 2

If your keypad is wall-mounted, take it off the mounting plate by pulling the top out a little bit and then lifting the keypad straight up.

Step 3

On the back of the keypad, locate and remove the battery compartment cover.

Step 4

Slip out the old battery or batteries -- some Honeywell systems use one nine-volt battery, while others use three AAs -- and insert fresh ones.

Step 5

Replace the battery compartment cover and slide the keypad back onto wall mount.

Replacing the Main Battery

To replace the 12-volt battery that powers your Honeywell security system, you will need to open the "can," the metal box that is usually installed in your basement or utility room.

Step 1

Using the key provided -- usually stored on top of the can -- unlock and open the can door.

Step 2

You'll see the 12-volt battery resting on the bottom of the can. Two wires, one red and one black, connect the battery to the alarm system with simple clips. Disconnect these using light pressure. Use your flathead screwdriver if you need it. Remove the old battery and set it aside.

Step 3

Place a new 12-volt battery where the old one was.

Step 4

Connect the black wire to the black terminal of the battery. Connect the red wire to the red terminal.

Step 5

Replace, close and lock the can door.

Step 6

Using the keypad, reset the alarm system to "ON." The "BATT" code should now be clear. If this is not the case, call your security company for a special reset code.