Your Guide to Buying Replacement Alarm Batteries Online

Most hardwired home and business alarm panels use a 12-volt sealed lead acid (SLA/AGM) backup battery, usually rated 4 to 7 amp-hours (Ah), with F1 or F2 spade terminals. All-in-one touchscreen and smart hub panels such as Vivint, Ring, Qolsys, 2GIG Edge and Xfinity use a smallerlithium-ion or lithium-polymer pack instead. To replace yours, match the old battery's voltage, chemistry and terminal or connector, then match or slightly exceed its capacity. This guide shows how to identify the battery your panel uses, what the numbers on the label mean, and how to swap it safely yourself.

Shop replacement alarm batteries or use the lookup table below to find the battery for your panel.

What Type of Battery Does an Alarm System Use?

Alarm systems use one of two kinds of backup battery, depending on how the control panel is built. The battery keeps the system armed and communicating when the power goes out, and the panel recharges it automatically once power returns.

Door and window sensors, motion detectors and key fobs are a separate job. They run on small lithium cells such as CR123A or CR2032 coin cells, not on the panel's backup battery.

Alarm Battery Lookup by Panel Brand

These are the replacement batteries BatteryClerk stocks for popular alarm panels. Wired panels use AJC® SLA/AGM batteries with a 12-month warranty. Touchscreen and smart hub panels use compatible lithium replacement packs with a 1-year warranty.

Don't see your panel? Read the label on your old battery (see the next section) and shop the full alarm battery collection by voltage and capacity, or call us at (888) 808-3520 for help matching a part number.

How Do You Read an Alarm Battery Label?

Your current alarm battery most likely has a model number plus some additional information that could be useful. Check on the actual battery for a number. Our example below shows a CA1240

It also includes some additional information which may be useful:

Voltage (V)

Voltage must match exactly. Wired alarm panels almost always use 12V. A 6V battery will not run a 12V panel, and a higher-voltage battery can damage the charging circuit.

Capacity (Ah or mAh)

Amp-hours (Ah) measure how much energy the battery stores, not how much current it delivers. SLA batteries are usually rated over 20 hours, so a 5Ah battery can supply about 0.25 amps for 20 hours. To estimate backup time, divide the battery's Ah rating by your panel's standby current draw. For example, a panel drawing 0.5 amps from a 7Ah battery would run about 14 hours in theory, and less in practice as the battery ages or gets cold. Lithium packs list capacity in milliamp-hours (mAh); 1,000mAh equals 1Ah.

Matching the original capacity is the safe choice. A higher-Ah battery gives longer backup if it fits the cabinet and your panel's manual allows it. A lower-Ah battery will work but shortens backup time, so it isn't recommended.

Terminal type (F1 or F2)

Most 12V alarm batteries use flat spade terminals. F1 terminals are 0.187 in (4.75 mm) wide and F2 terminals are 0.250 in (6.35 mm) wide. In BatteryClerk's catalog, 12V 4.5Ah and 5Ah alarm batteries use F1 terminals, while 12V 7Ah batteries use F2. Your panel's wire leads are sized for one or the other, so match the original.

Chemistry

Replace an SLA/AGM battery with another SLA/AGM battery, and a lithium pack with a matching lithium pack. Don't install a lithium battery in a panel built for SLA unless the panel manufacturer approves it, because the two chemistries need different charging profiles.

Physical size

The battery has to fit the cabinet or battery bay. The common 12V 4.5Ah and 5Ah alarm battery measures 3.54 x 2.76 x 3.98 in. The common 12V 7Ah size measures 5.94 x 2.56 x 3.7 in, so check the space before upsizing.

So to look for our battery that matches, we head to batteryclerbestseller.com and do a search for “CA1240”. The top results also match the brand of our old one:

At $18.49 you’re sometimes looking at a quarter of the price from most alarm companies and half that of the manufacturer.

Should You Replace the Battery Yourself or Call Your Alarm Company?

For most homeowners, replacing a backup battery is a simple DIY job that takes a screwdriver and a few minutes.

• Do it yourself if you own the equipment and can reach the panel. You pay only for the battery: AJC® 12V alarm batteries for common wired panels are under $20 on BatteryClerk at the time of writing, and you don't have to wait for an appointment.
• Call your alarm company if your service contract already covers battery replacement, if you lease the equipment and the agreement requires the provider to service it, or if the panel is hard to reach safely. Expect a service fee on top of the battery; ask your provider for the amount first.
• Use a licensed technician for commercial fire alarm panels. Their secondary power is governed by NFPA 72, which requires enough standby battery to run the system for 24 hours and then operate in alarm, and changes are usually documented as part of required inspections.

Property managers replacing batteries across many sites can request volume pricing through our wholesale battery program.

How to Replace an Alarm System Backup Battery

These steps apply to wired panels with a 12V SLA battery in a metal cabinet. Always follow your panel manufacturer's instructions where they differ.

What you need: the replacement battery, a screwdriver or cabinet key, and optionally a multimeter to check the new battery's voltage.

1. Put the system in test mode. If your alarm is professionally monitored, call the monitoring company and ask them to place your account on test. Opening the cabinet or disconnecting the battery can send tamper or low-battery signals, and test mode prevents a false dispatch.

2. Disarm the system and leave AC power connected. The panel keeps running on household power while the battery is out, so you don't lose programming.

3. Open the panel cabinet and note the wiring. The red lead connects to the positive (+) terminal and the black lead to the negative (−) terminal. Take a photo before you disconnect anything.

4. Disconnect the black (negative) lead first, then the red (positive) lead. Pull on the connector, not the wire, and don't let the bare leads touch each other or the metal cabinet.

5. Remove the old battery and check the new one. Confirm the new battery has the same voltage and terminal size. A healthy new 12V SLA battery should read about 12.6V or higher on a multimeter; the panel will finish charging it.

6. Connect the red (positive) lead first, then the black (negative) lead. Push each connector fully onto its terminal.

7. Close the cabinet and test. Many panels let you run a battery test from the keypad. If not, the low-battery trouble clears on the panel's next automatic battery check, which can take several hours to a day while the new battery charges.

8. Take the system off test and recycle the old battery. Call the monitoring company to restore normal monitoring, then take the old battery to a recycler (see below).

How Often Should You Replace an Alarm System Battery?

A 12V SLA alarm battery typically lasts 3 to 5 years in standby service. There are quite a few other factors that influence lifespan. Heat shortens that, and so do frequent or long power outages that drain the battery deeply. Replace it sooner if the panel shows a low-battery trouble that doesn't clear after a full day on AC power, or if the battery is swollen, cracked or leaking. For testing tips and how to keep your system ready for outages, see Alarm System Replacement Battery Tips.

What Should You Do With the Old Alarm Battery?

Never put an alarm battery in household trash. Lead acid batteries are among the most recycled products in the United States; the Battery Council International reports a recycling rate of about 99%. Take used SLA batteries to a battery retailer, auto parts store or local recycling center. For lithium packs, cover the terminals with tape and drop them off at a Call2Recycle location. See our battery recycling page for more options.