How to Test an Alarm Battery with a Multimeter

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Today’s alarm systems hugely depend on batteries more than ever. A typical home alarm system has a back battery for the control panel. Such batteries would furnish power in case your home encountered a power loss. 

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In this event, the alarm system would still work for a time and continue to offer protection for your property. 

With today’s wireless alarm systems, the battery is even more important than ever before. Each wireless device is powered by a battery. Does your wireless device feature a weak battery? Then expect that your system will produce a problem that will inform you of the issue and where the issue exists.

That’s another reason to have a precise zone list for your alarm system. After all, the last thing you like to do is chase a low battery signal and not be able to change the proper battery. 

What will happen if your power is lost?

Keep in mind that your home security system is typically functioning on house current or AC. The backup battery is then checked by the control panel for the correct operating voltage. When the voltage goes under a base level, the control panel will then produce a system battery problem.

On the other hand, when the AC to your control panel is lost, then another trouble will be produced that will suggest an AC loss. 

How long does your system backup battery last?

There’s no exact estimation of how long the system battery would last. However, remember that it will depend on the A/H amp hour rating of your battery and the overall current draw of your alarm panel. That’s normally based on the number of devices linked to your system.

Basically, your alarm system without an alarm condition would operate for at least a 24-hour time. When the alarm system is triggered while using the battery backup, the backup time will be much less. When the system remains in battery backup mode for a longer time, and the battery goes dead, it will help if you change the system battery. 

If you have a new alarm system battery, the warranty is normally for one year. 

How long do wireless batteries last? 

You will find a wide array of batteries used in wireless alarm systems. They vary from your average double battery to nine volts. The newer wireless devices utilize a much smaller battery like a lithium three-volt battery. 

Such batteries let for a much smaller device that complements well with the home. The time length that your devices will last varies on how often you use them. Further, your wireless devices are on standby most of the time to save the batteries. Still, they’re always ready to perform if they’re called upon to do so. 

A decent estimate of time would be at least a year. As a rule, make sure you change the batteries every once a year. That can be costly based on the size of the system you have in your home. But you can always wait until the devices report a low battery condition.

Do you start to notice a number of devices reporting low battery? Then it will help if you change all of the batteries of the devices or, at a minimum, ensure you buy all the batteries you’d require. Buying a larger amount of batteries allows you to save cash and to know you’ll need them later on. 

How should you test the batteries of your alarm system backup? 

You can test the battery of your alarm system with a digital multimeter. Here are the steps you need to follow to do this:

  • Press and hold the test button on your alarm system until the alarm sounds. That suggests a good battery.
  • Now, remove the battery from the compartment if your alarm system uses the battery as a backup only. Slowly turn off the circuit breaker supplying power to the system. Push the test button on the system to make sure the alarm doesn’t sound. Install the battery again and push the test button. Your battery is still in great condition if the alarm sounds.
  • For the third step, remove the battery from the system. Set your multimeter to DC current. Pick a DC range that is higher than the volt of your battery. Based on your multimeter, that could be ten or twelve. 

Connect the red lead to the positive post of the battery and the black lead to the negative post. Read the current displayed by the multimeter. The meter must give a reading of 4.8 to 9.6 volts if the battery is still good.

  • For the final step, test the batteries installed in the alarm system a bit differently. Remove the batteries from your unit. Plug the battery into a battery tester. Your tester must show if the battery is low on power or if it’s full. 

How do you change your alarm battery? 

Ensure you get in touch with your monitoring company every time you do any work on your alarm panel and put the system to the test. They will ask questions on how much time you’ll need. 

Here are the steps you need to do:

  1. Call to have the system put on test.
  2. Remove the leads from the battery.
  3. Disconnect the system power by:
  • removing the system transformer from the house power 
  • removing one power lead from the control panel 

For the second option, it will help if you don’t short the lead out on any other terminals or touch the cabinet. You can add a wire nut on the loose lead or insert a piece of electrical tape on the bare wire. 

  1. Disconnect the old battery.
  2. Install the new battery and insert the leads back in. Ensure you check the correct polarity when changing the leads. 
  3. Plug the battery first, then insert the transformer back, and everything must be back to normal. 

Final Thoughts

After doing all the steps, your alarm system will power back up, and everything must be back to normal. Ensure you call the monitoring agency when everything is done and disconnect the system from test mode.

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