[Nexus 5 Q&A, Help & Troubleshooting] Elias_grodin:
Hi,

The battery life of my Nexus 5 has taken a dramatic hit since the 4.4.2 update. I think the culprit is Android System but the GSAM battery graph seems to suggest that the culprit is Android OS kernel. My Nexus 5 is on 4.4.2, unrooted, stock ROM and the build no. is KOT49H.

In short, my phone does not seem to have a wakelock issue but I can't verify because 4.4 does not allow wakelock access without root. It sleeps fine at night and in daytime when it is not in use. I only lose around 5% or less overnight with 2x battery turning off the data connection and only turning on data connection once every night. The problem is the Android System which drains at least 17% (sometimes 25%) of battery everyday and routinely sits on top my of battery usage chart with or without me actually using the phone. My usage per charge is typically around 6-7 hours with around 1 hour 45 minutes screen on time. I had extraordinary battery life before the update to 4.4.2 (lasting more than 1 day with over 3 or 4 hours screen on time). Now my battery life is completely shot. The battery graphs attached already represent one of the better days. Some days the Android system will drain at 25% or more. You will note my phone relatively slept fine without draining at night in the first 7 or 8 hours and then the battery drain started to take a nose dive after I woke up. I feel that whenever I start using the phone (with the screen being turned on), the battery drain will occur. My observations are as follows:

1. I use LTE but the reception at my home and work for LTE is not good so the radio jumps between LTE and H+ from time to time however I do not think the radio jumping contributes that much to the drain. The drain stays the same even when I am at a place with good LTE reception. I use wifi at home but i cannot connect to wifi at work (which sadly is another issue). The wifi is always off unless i use it at home. I do NOT have wifi scanning in the settings. I have wifi battery optimization on. I never use bluetooth.

2. My google now is off. My location setting is completely off with no location reporting etc..

3. My Google + auto back up is off. I do not use Facebook, Facebook messenger, Instagram, snapchat etc. I mostly use Feedly, Whatsapp, Gmails and look at stock quotes every day. I seldom take pictures, videos or listen to music.

4. I only have one widget dashclock widget. I have removed feedly and stock quote widgets from the home screen but they don't seem to affect my battery usage that much.

5. I use Automateit but only have a few rules such as setting vibrate on weekdays etc.. I do not have any profiles which are related to GPS or location which i understand would drain battery. I also use Dynamic Notification, Light Flow, Lux, Nova Launcher, Notification Toggle and the memory in general is always below 65% in the background. I also use 2x battery to save battery which is set at switching off data after I turn off the screen and it will only turn data in the background every 10 minutes.

6. I have tried safe mode and 9 out of 10 times the Android system drain remains the same. The only way to lower the Android system drain (albeit temporary) is when I turn off the phone and plug it in for a charge, then turn it on when it is full and still plugged in. After I unplug it, the Android System drain will lower to say 7 or 8 % but it will slowly creep back up to 20% within an hour or so.

7. The CPU usage overlay routinely has 9 + readings on the top when the screen is turned on (but with no app running). I think it means very high CPU usage.

8. I do not think Feedly is causing any problems. I deleted the app and the drain remains. I also do not think GSAM is that useful as pointed out by another member here. It points to one app. You delete that app and then the drain remains it will point to something else.

9. I have been using Greenify (non-root) but it does not seem to help with my battery drain as the drain might be caused by system apps or processes within the OS.

I don't know what else to do and this problem has been troubling me for more than 1 month now. Please help !

Update on 24/2/2014:

I have given up and factory reset my phone. After I reset my phone, the apps were installed via Google Play automatically. I also switched to ART. It was fine initially for at least one day. The apps were there but I did not use or enable most of them as I wanted to transfer all my data and tweaked the settings in one goal. I mostly just used Feedly, Whatsapp and Maps for navigation. Even with Maps and high accuracy GPS on, the Android System would go below 10% even though it would temporarily increase to say above 20% during navigation. This morning, I thought the battery seemed ok so I enabled Lux, Dynamic Notifications, Lightflow, Automateit, Nova Launcher and restore the settings to most of the apps.

The Android System drain came back within 2 hours and hit 25% of the total battery drain. My phone's battery dropped from 100% to 40 % in less than 5 hours and the screen on time was only around 1 hour! I never did any battery intensive actions. The most was turning on the phone to check my battery and whatsapped less than 10 messages back and forth ! Since the drain re-appeared, I have turned off completely the location setting, Google Now, sync for Google Plus, auto-backup for Google Plus. I have removed all widgets and disabled Dynamic Notifications, Nova Launcher, Light Flow, Lux. The drain still remains the same at 23% or more.

This is driving me absolutely crazy and I am sick and tired of spending so much time and energy on sorting out the cause for drain (and to no avail!) I spent a lot more time on trying to fix the phone than really utilizing the phone for my benefit !! I just sent an email to the Google tech support and hope they will help instead of sending me generic self-help sheet. Thanks all for listening and trying to help. I am just really disappointed with Google this time.