Just about every new version of Android has reportedly improved battery life for end users... with a range of successes and failures over the years. In the upcoming Android O, Google is banking on a new feature called background limits to extend battery longevity. The basic idea is that the system will automatically limit the active capabilities of background apps, in a way that won't be detrimental to users while reducing overall resource use.

These limits come in two primary forms: execution limits and location limits. The former basically restricts system access to certain processes when either the app or portions of its activities are not in the foreground and being actively used. Apps will have access to high-priority resources by using explicit broadcast requests in their manifests. Location limits are specifically for apps that require access to a device's location services (GPS, Wi-Fi, mobile triangulation, et cetera), as that's a particularly big draw on the battery. Apps can have access to those tools when they're in the foreground or using the GeoFencing API, or when using a passive "listener" that borrows location data from a foreground app.

The new tools should allow phones and tablets to get a considerable boost in battery life... so long as enough developers don't try to abuse or work around the background limits. Expect to see some buggy or non-functioning apps, especially those that use location, if you've already updated to one of the developer preview builds. Hopefully several months of preview and beta time will mean smooth sailing as Android O is released to retail devices.

Source: Android Developers