Alarm system batteries come in many varieties, depending on the type of system they are used in. The most common main panel types are 12-volt batteries in either 4- or 7-amp/hour capacities (12v, 4ah battery and 12v, 7ah battery)
You’ll know you need a new battery when the system keypads begin beeping, and display a “low battery” message or a “trouble” light on the keypads.
If your system is beeping and you're not sure how to stop it, see "My Alarm Keeps Beeping - What Can I Do?".
If you have a burglar alarm monitoring service, you will also have gotten a call from the central monitoring station alerting you to the problem.
Learn more about home alarm system monitoring.
Here I’ll list some of the many different types of security system batteries out there, and how you can deal with them when they have problems. If you don’t want to handle this yourself, your alarm dealer will be happy to take care of it for you.
I always recommend marking the installation date on all new batteries, just for reference. Use a Sharpie or other permanent marker. This may not show up too well on a black battery case, so just write on a piece of masking tape.
For more details on how to do this, see this page on alarm battery replacement.
These panels often use a rechargeable battery pack rather than a sealed lead-acid battery. It’s best to order this type of alarm system battery by the make and model of panel, since the connector must match the panel exactly.
You’ll need to verify what kind of smoke detectors you have. There are 3 main types:
For the first 2 types, remove the detector from its base plate and open the battery compartment.
Remove the old battery. Insert the new battery, making sure it makes contact with the terminals inside.
Close the compartment and re-attach the smoke to its baseplate.
Many smoke detectors use common 9v alkaline batteries you probably have on hand.
The 3rd type of smoke detector could be one of 2 designs: Hardwired or wireless.
Hardwired smoke detectors are powered by the main alarm panel through the wiring, and have no battery inside them.
If you have a wireless smoke detector, you’ll need to first put your alarm system on “Test” if it’s monitored by a central station. Then you can proceed to change the battery as usual.
Many brands of wireless smoke detector use the popular CR123 lithium alarm system batteries.
Wireless transmitters come in many different varieties, including
wireless keyfobs, pendants, and door and window sensors. Check each type
of transmitter you have to see which batteries you’ll need.
In the past, wireless home security alarm batteries included 9-volt, “AA”, and “AAA” alkaline batteries.
Newer systems have moved to the higher performance lithium batteries. Within this type there are many “button” or “wafer” cells, including:
…and there are others.
If the plastic cases on your transmitters are brittle from heat or age they may break when you remove them.
Replacement cases are available for many brands of wireless security sensors including Ademco. Search for cases by brand name and model number found on the transmitter base.
Many wireless keypads use one of the standard alkaline batteries previously mentioned.
You can usually swap these out with fresh batteries and begin using the
A few wireless keypads have a battery that is factory-soldered onto the circuit board. This kind must be sent to the manufacturer for battery replacement. If the maker is no longer in business or parts are unavailable, your choices are limited:
In most cases, your money is better spent on a new system, rather than
on trying to resuscitate a failing wireless keypad. Even if you do get
the keypad working, the rest of the equipment has
already taken a lot of wear. Best to get a new one, and enjoy some of
the many modern features available now.
Even after all your efforts, you may decide that your system is
beyond reasonable repair. If this happens, find out what a new system
will cost by getting a few Free Home Security Systems Quotes from companies in your area.
These can help you decide whether to pull the plug on the old system, install a new system yourself, or step aside and let a professional security company do the work.
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