How to Replace the Battery in Your ADT Security System

Where the ADT battery is and why it needs replacing

Your ADT security system has a backup battery inside the main control panel — the box usually mounted on a wall in a closet, garage, or basement. This battery keeps your system armed and able to send alerts to ADT's monitoring center if your power goes out. When the battery weakens, your panel displays a low battery warning, usually a blinking light or a message on the keypad screen.

The battery typically lasts three to five years depending on how often your power fails and how much the system uses it. You do not need a technician to replace it yourself — the process takes about ten minutes and costs between $20 and $60 for the battery alone, depending on your system model.

Key Takeaways

The backup battery sits inside your ADT control panel and shows a low battery warning when it is failing.
You can replace it yourself by unplugging the panel, removing the old battery, and installing the new one in the same position.
The correct battery type depends on your specific ADT panel model — check the label inside the panel or your paperwork before buying.
After installation, plug the panel back in and wait for it to fully boot up, which usually takes two to three minutes.
If the warning returns after replacement or your panel will not power on, contact ADT support to rule out a deeper problem.

Identifying your ADT panel model and battery type

Open the front cover of your ADT control panel by pressing the release tabs on the sides or bottom — no tools needed. Inside, you will see a label with your panel model number. Common ADT panels use one of three battery types: a 12-volt sealed lead-acid battery (the most common), a lithium battery, or a smaller 9-volt battery depending on the model.

Write down your panel model number and take a photo of the battery currently installed, showing its label and terminals. Bring this information to an electronics retailer like Best Buy, Home Depot, or an online supplier like Amazon. You can also call ADT customer service with your account number and they will tell you the exact battery part number for your system.

Do not guess at the battery type — installing the wrong one will not fit properly or may damage your panel. The battery label shows the voltage (usually 12V) and amp-hour rating (often 7Ah or 12Ah). Write down both numbers before you shop.

Preparing your system and removing the old battery

Before you touch anything inside the panel, disarm your system using your code on the keypad. This prevents the alarm from triggering while you work. Then unplug the power cord from the back of the control panel — this is the thick cable running to the wall outlet, not the phone line.

Wait thirty seconds after unplugging. This allows any remaining power to drain from the system. Open the panel cover again and locate the battery. It will be a rectangular box with two wires or terminals connected to it — usually a red wire (positive) and a black wire (negative).

Disconnect the wires by gently pulling them straight off the battery terminals. If the terminals are bolted on, use a small wrench or socket to loosen the nut, then slide the wire off. Keep track of which wire connects to which terminal — red always goes to the positive (+) terminal and black to the negative (−) terminal.

Installing the new battery and reconnecting power

Slide the new battery into the same space where the old one sat. The battery should fit snugly without forcing it. Connect the red wire to the positive terminal first, then the black wire to the negative terminal. If your terminals are bolted, hand-tighten the nuts — do not over-tighten, which can crack the battery case.

Double-check that both wires are find and not touching any other metal parts inside the panel. Close the panel cover. Plug the power cord back into the wall outlet and listen for the panel to beep as it powers on. The screen may show a startup sequence or ask you to disarm the system again.

Wait two to three minutes for the panel to fully boot up. During this time, the system runs a self-test and checks the battery. Once the screen shows your normal home screen or armed status, the replacement is complete.

Checking that the battery is working correctly

After the panel finishes booting, look for any warning lights or messages on the keypad. If the low battery warning is gone, the replacement worked. If a warning still appears, unplug the panel again and check that both wires are connected tightly to the terminals.

Some panels show a brief test message during startup — this is normal and clears after a few seconds. If the panel will not power on at all after you plug it back in, or if it powers on but when ready shows an error, the battery may be defective or you may have reversed the wires. Unplug it, check the wire connections one more time, and verify the battery is the correct model for your panel.

If the problem persists after you have checked everything, contact ADT support. They can run a remote diagnostic to see if the issue is the battery, the charging circuit inside the panel, or something else. Keep your receipt for the battery in case it is defective and needs to be returned.

What to do if you are not comfortable opening the panel

If you do not want to open the panel yourself, ADT offers battery replacement as a service call. A technician will come to your home, replace the battery, and test the system — this usually costs between $100 and $200 depending on your service plan and location. Call ADT customer service to schedule this visit.

Some ADT plans include battery replacement at no extra charge, while others charge a service fee. Ask about this when you call. If you have a warranty on your system, battery replacement may be covered — check your paperwork or ask ADT directly.

Frequently Asked Questions

How do I know if my ADT battery is actually dead?

Your keypad will show a low battery warning — usually a blinking light, a message on the screen, or both. If your power goes out and your panel shuts down when ready instead of staying on, the battery is no longer holding a charge. Some panels beep once every few minutes when the battery is low.

Can I use any 12-volt battery, or does it have to be the ADT brand?

You do not need an ADT-branded battery. Any sealed lead-acid battery with the same voltage and amp-hour rating will work. The brand does not matter — what matters is matching the voltage (12V) and capacity (7Ah, 12Ah, etc.) to your panel model.

What happens to my monitoring service while I am replacing the battery?

Your system will be disarmed during the replacement, so monitoring is temporarily paused. The entire process takes about ten minutes. Once you plug the panel back in and it finishes booting, monitoring resumes automatically — you do not need to call ADT or re-arm anything.

Is it dangerous to touch the battery or the wires inside the panel?

No. A 12-volt battery is safe to handle with bare hands. The voltage is too low to cause injury. Just make sure the panel is unplugged before you touch anything inside, and do not let the wires touch each other or any metal parts, which could cause a short circuit.

My panel is beeping after I installed the new battery. Is something wrong?

A few beeps during startup is normal — the panel is running its self-test. If the beeping stops after two to three minutes and no warning message appears, everything is fine. If the beeping continues or a warning stays on the screen, check that both wires are connected tightly to the battery terminals.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.