A typical ADT home security system consists of a central control panel and a number of peripheral devices, including smoke alarms, door and window sensors and motion sensors. All of these components—including the control center, where the chimes are located—have batteries, and you'll get a warning beep and a message on the LED screen when one of them is weak. If the weak battery is in the control panel, you may need to special-order a new battery, and you may need a key to open the panel, depending on the model. In most cases, though, all you'll need to open the panel is a screwdriver.
Check the Manual
If you have any questions about your ADT system, including the type of battery you need, the first place to look is in the owner's manual. If you don't have one, you can find a virtual copy at MyADT.com. The manual will also explain how to silence the low battery alarm. Depending on the model, you may have to:
- Key in the security code and enter [OFF].
- Press  +[security code].
- Enter [OFF].
- Enter [STATUS].
- Press the pound key [#].
- Simply press any key.
Don't have access to a manual? Try each of the above options, starting with the simplest. You can always call ADT at 1-800-588-2159 for further instructions once the annoying beeping has stopped.
Contact ADT Before You Begin
To avoid triggering an alarm and a response from ADT, you need to place your system on TEST before you remove any of the batteries. There are two ways to do this:
- Go to MyADT.com and log in with your username and password.
- Call ADT at 1-800-588-2159. You'll need to supply your ID code and the zone or device with the low battery. You should have the replacement battery in hand before you call.
Changing a Battery in a Peripheral Device
Put the keyboard on the main control panel in test mode by entering your access code, followed by 50.
Locate the device with the weak battery and open the battery compartment. You may need a flat-head screwdriver to open the door. If the device is a smoke alarm or motion sensor, rotate it counterclockwise by 90 degrees and turn it over. The battery is in the back.
Remove the old battery or batteries, and wait 30 seconds before inserting replacements. If the device takes two batteries, replace both of them. Close the battery door. If you replaced a smoke alarm or motion sensor battery, screw the device back to the mounting with a clockwise 90-degree turn.
Key your security code into the keyboard on the main panel and press the "Test" button. After the system verifies all its components and gives you an all-clear message, key in your security code once more and press "Off." Notify ADT online or by phone that the test is complete.
Changing a Battery In the Control Panel
Open the panel door. You may need a flat-head or Robertson screwdriver to do this. On some units, you just need to squeeze a pair of tabs with your fingers.
Verify that the replacement battery is identical to the one in the unit. Take the old battery out of the panel and disconnect the wires. Attach the wires to the new battery and insert it into the mounting in the battery compartment. Close the door.
Disregard any warning beeps that occur after you complete the replacement. New batteries do not come fully charged— it takes about eight hours for one to charge once installed. The alarm system will be fully operational as soon as you install the battery, however.
Contact ADT to discontinue the test.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.