Why is Android System always keeping my phone awake? I woke this morning and discovered that my phone's battery was at 70% capacity, even though it had been fully charged when I went to sleep. I went into the battery settings, and found that Android System is primarily responsible, having kept my phone awake the entire time. I searched a bit, and this does not appear to be normal behaviour. Reception and wifi are fine, and power saving is on. I'm hoping that there is an explanation and solution to this.
A common workflow to track down deep-sleep / wake-lock issues:


Install CpuSpy
Install BetterBatteryStats
Turn off your phone
Fully charge it while turned off
Unplug the cable
Start the phone, unlock it and open some apps like email, browser, facebook, and close them again
Don't touch your phone, let it be on your table for a hour
Open CpuSpy

"Deep Sleep" should be the longest bar of all. If not, the CPU works because a process (App, Service) constantly wakes your phone up or you use a non standard Kernel/ROM which has a Deep Sleep problem

Open BetterBatteryStats

Set the first dropdown to "Kernel Wakelock" and second to "Since unplugged", then see if any app you've installed appears in the list, using high % numbers (waking your phone up)
Then set the first dropdwon to "Partial Wakelocks" and check again for any app waking your phone up with a high % number

Uninstall the app which causes wake locks (preventing your phone from deep sleep)
If the problem still persists, google for further instructions with the following pattern:

"wakelock + [appname]" without the brackets, enter the app or service name which causes high percentages in BetterBatteryStats, and google without the quotes!