At any time, you can check on the status of each of your smoke alarms and the Smart Batteries inside of them. The Alarm Status screen will show you the status, including if there is low or critical smart battery life.
If you tap on an alarm, you'll get to the alarm detail screen. On this detail screen, you can see the location of your alarm, that particular alarm's history of Smart Battery activity, battery life, and assigned monitors. You can also enter the building address where the alarm is installed.