Will I be notified when the battery is low?

You will NOT receive a push notification, to your phone, when the battery level is low. However, if you have geofencing enabled, these notifications will let you know that the battery level is too low to unlock remotely. 

Energy Saving modes.

Geofencing explained.

Within the Array app, the battery status and percentage is shown on the lock screen. This will help you to keep track of the charge level.