If you’re one of the unlucky few Google Nexus 5 owners who have been experiencing issues with battery drain, you’ll be pleased to know that Google is aware of the problem and is working on a fix.
The bug involves the Android 4.2.2 camera application, and is triggered when the camera is opened by the user or even triggered in the background by another app (Skype users seem to be experiencing this bug in high numbers). When triggered, the device’s CPU will max out, resulting in quick battery drain and abnormal device warmth. Additionally, this doesn’t just affect Nexus 5 owners, but other devices that have been updated to Android 4.4. 2 as well.
To confirm that you are experiencing this bug, just navigate to Settings > Battery. If you notice that mm-qcamera-daemon is consuming an abnormal amount of battery, you will be forced to reboot your phone in order to stop it. As of now, this is the only solution.
Others have reported that uninstalling apps like Skype can help, but this isn’t guaranteed since it can be triggered by the native camera application itself.
Luckily, Google has acknowledged this issue officially and has promised a fix in a future maintenance update. Important to note is that Google recommends all non-Nexus users report this bug to their respective device manufacturers, as OEMs will have to fix it themselves in future OTA updates (HTC users, good luck).[Google via Phandroid]