The SEM-Honeywell/ADEMCO Vista uses a rechargeable (sealed lead-acid type) 12VDC, 4Ah minimum backup battery. The backup battery typically does not need to be replaced for at least 3 years. 

Note: For UL installations, use a UL listed battery backed supply. The battery supplies power to these keypads in case of AC power loss. The battery-backed power supply should have enough power to supply the keypads with the UL required minimum standby power time.

To replace the battery in a SEM-Honeywell/ADEMCO Vista:

If desired, put the system in test mode with the monitoring station before proceeding. 

1. Disarm the system.
2. Power off the panel.
   1. Unplug the AC power transformer.
   2. Disconnect the backup battery.
3. Remove the old backup battery. 
4. Place the new 12-volt backup battery in the cabinet.
5. After all connections to the control are completed and AC power has been applied, connect the red and black flying leads on the control board to the battery.
   • The panel does not power up initially on battery power only. The transformer must be plugged in first, and then connect the battery.

     Important: Do not attach these leads to the battery terminals until all connections are completed.