Android is a sophisticated multitasking operating system and because of this, combined with a massive number of different hardware permutations, means that not every device or software build is as robust as customers might expect. In recent releases, Google has refined Android and improved it across the board for the user interface, application performance and battery life. However, there are what appear to be glaring issues embedded into Android that have been persistent through multiple versions and despite being flagged in Google's own Android bug reporting Group, still have not been fixed. One of these issues is the battery drain that started with Android 5.0 Lollipop.
The symptoms of the battery drain appear to be that applications keep the radio active, which causes a noticeable battery drain. In older versions of Android - looking specifically at Android 4.4 KitKat - applications would wake the device, access the Internet via the mobile data connection, and then close the data connection down thus putting the device back into an energy sipping mode. There does not appear to be an increase in data usage for most applications, instead it appears that something within the software code simply maintains an active data connection, which prevents certain hardware components from falling asleep. Unfortunately, it appears that the Google applications are the most guilty of keeping the data connection open although this is arguably very much to be expected given that we are discussing Android devices. The matter is complicated because Google Play Services is one of the most active applications when it comes to keeping the mobile data connection alive, but this application performs a myriad of different tasks on our Android devices and it is difficult to ascertain what, exactly, is causing the battery drain. There is another complication in that how Android presents battery use statistics has been changed between version 4.4 KitKat and 5.0 Lollipop, which means a comparison of the battery usage breakdown information before and after is not especially useful. However, what customers report - that a device upgraded from 4.4 to 5.0 - loses charge quicker when idle compared to before. This is despite Google's efforts to improve energy efficiency.
Some of our Nexus devices have either already received, or are are about to, the update to Android 6.0 Marshmallow and unfortunately, early reports on the Internet, point to the mobile radio battery drain bug still being persistent in the release version of Android Marshmallow. This is despite a Google project manager reporting: "In investigating the bug-reports shared in this tracker we discovered and fixed an issue where the device was waking up unnecessarily. There are some fixes for additional improvements. This particular fix will ship in Android M, and is just one in a number of efforts to improve battery life." This may be a slight play on words because the issue appears to be not so much that a device is waking up, but more that it will not fall asleep after it has connected to whatever online service it needed. We've seen a number of improvements incorporated into Android designed to enhance battery life, such as a network activity scheduler designed to allow as many applications as need Internet connection to go online at the same time, thus avoiding waking the device up unnecessarily. The network scheduler relies on application developers to utilize the feature. However, this is a developing story and it is unclear how widespread the issue is, if it is exactly the same issue, and if Google has made any progress with the fix.