This app helps reduce battery drain by regulating your data connections and by syncing schedule, screen settings and other device components. You configure it by enabling the profile for the level of juice-saving you desire: Balanced, Aggressive or Extreme. The Balanced profile is fully automatic and doesn't require your input. The Aggressive profile automatically disables data connectivity when the battery is low, which you can turn back on when needed by clicking the shortcut in the notification area of Android. The Extreme profile keeps data connections disabled by default; they can be turned on manually and you can whitelist apps that always need connectivity. For example, it can automatically disable the Wi-Fi if you aren't connected to a network or you aren't nearby networks you frequently use.

The Free version of JuiceDefender supports the Balanced and Aggressive profiles and offers limited mobile data connection controls and sync scheduling. The Plus version ($1.99) offers more setting customizations for the Aggressive profile and adds support for the Extreme profile. It also adds Wi-Fi control and more customization for the sync schedule. The Ultimate version ($4.99) adds AutoSync, screen timeout and screen brightness controls and offers additional sync scheduling customization. If you have a rooted device, it also lets you control CPU speed, GPS control and 2G/3G switching.

You can customize the functionality even more with the Customize and Advanced profiles. All versions of JuiceDefender support these profiles, but there are limitations on what settings you can configure in the lower versions. However, you can still see and review the settings to understand what the app offers in the higher versions.

Despite the rather confusing number of configurations and versions, I found JuiceDefender to be straightforward to configure and use. Sorting through the differences between the three versions was a bit of a mind-boggler, but it does offer a comparison table via a button in the app to help. Remember, if you can't change a setting, it's probably because it's disabled and only included in a higher version.