The 1.0 version of BatteryAlert for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. BatteryAlert for Mac lies within System Tools, more precisely Battery Utilities. This free Mac app was originally produced by Sqwarq.
From the developer:
BatteryAlert is an lightweight application that monitors and notifies you of Bluetooth battery levels via Email, Messages, Notifications, or Alerts. The program features live Dock tile, offering easy visual indication of current battery status at all times.
You may want to check out more software for Mac, such as iPodBatteryIndicator, Mi-Fi Monitor or Battery Spy, which might be similar to BatteryAlert.