When it is time to replace the battery in your motion detector, you will see an alert on your system panel period.
The Qolsys QS1231-840 motion detector requires 2 AAA batteries, which can be purchased from Indiana Alarm, local hardware store, mass retailer, or battery store.
1. Locate the sensor with a low battery on either your system panel
2. Leaving the sensor backplate in place, open the cover by pressing the tab at the bottom of the sensor.
3. Remove the old batteries.
4. Make sure the area where the batteries are stored is clean and there is no corrosion.
5. Place 2 new AAA batteries into the sensor.
6. Put the cover back on starting with the opposite end from which it was opened. You should hear a snapping sound if it closes correctly.
7. Check if the low battery status has cleared