How Long Does the Interlogix Simon XTi or XTi-5 Backup Battery Last?

The Interlogix Simon XTi or XTi-5 backup battery lasts for about two to three years before requiring a replacement. To replace the battery, first unplug the AC transformer from the wall. Then open up the panel, and disconnect the old battery. Connect the new one, and close the panel.

A message will be displayed on the XTi or XTi-5 System when its backup battery is low. This is an indication that the old battery should be replaced as soon as possible. You can replace the backup battery for the system by completing the following steps:

1. Open the panel. Before attempting to open the panel, make sure that the system is disarmed. Then unplug the AC transformer from the wall outlet. Carefully pry off the panel's outer trim by using a flathead screwdriver that is inserted into the slot in the lower-right corner of the system. Then push in the two upper tabs and pull the panel away from its back cover. This will give you access to the interior of the system.

2. Remove the old battery. Locate the backup battery pack inside the panel (A). Unplug it from its connector port inside the panel (B). Slide your finger under the battery, next to the plastic locking tab (D) and pull up. Do not push on the locking tab, it should slide out of the way on its own. Remove the old battery and dispose of it in a safe and proper manner.

3. Connect the new battery. Take the new battery, and plug its connector into the corresponding port inside the panel (B). This is the same port that the old battery was connected to. Then click the battery into place on the system so that it is nice and secure.

4. Close the panel. With the battery replaced, push the panel back onto the back cover, and click it into place. Then reapply the outer trim, and make sure that it snaps into place. Finally, plug the AC transformer back into the wall outlet. Any low battery warnings should be restored. However, you may need to power cycle the panel to clear any low battery messages. The new battery may also need some time to charge before it reaches full strength.