Help 4.2.2 Android OS Battery Drain

[sae160]

My Nexus 7 (2012), running 4.2.2 stock rooted, has been dying in about 2 days with very minimal use. When I check the stats, "Android OS" is the leading consumer. I'm wondering if there is a bug or known drain in the software?

With my limited use/screen time, I guess Android OS being number one doesn't surprise me, but I should be getting way more than 2 days on a charge, especially if I have WiFi off. My other devices would not go through a full charge in weeks under the same conditions.

Any ideas on how to resolve or mitigate this battery drain? Would a battery stats app enable me to further diagnose the problem?

Thanks.

 

[funkylogik]

Can you post a screeny of the second part of the battery stats mate? (Tap the graph)

 

[jlede]

Wait you are complaing about not getting 2 days of batt life I got 10-12 hrs max once I usually get like 6-8

 

[funkylogik]

I get like an hour screen time per 10% but days on standby (havent tested how long)

 

[sae160]

Yes I'm complaining. My LG G2 gets near 100 hours with frequent use. My iPod touch is 5 years old and can sit unused for weeks without dying. If I leave my Nexus alone on a full charge with WiFi off, it absolutely should last more than 48 hours.

I'll post the second screenshot at the end of my current discharge cycle.

 

[funkylogik]

Since its standby time thats bad, its probably an app waking the CPU (wakelock)
Usually social networks are the worst offenders.
In the second stats screen youll be able to see if the cpu being awoke while the screen is off but it wont tell you whats doing it.
The app Wakelock Detector is a nice simple way of seeing whats responsible.
If getting notifications in real time isnt important to you then i recommend DS Battery Saver.
I use it on my phone. when the screen is off, it disables data and hibernates apps so they dont wake the cpu to check for notifications but lets them wake every 1hr/2hr/4hr for a minute to check.
On my tab i dont need it tbh. if im not gona use my tab anytime soon i just power it down :thumbup:

 

[ArcFlash]

I have found that if you turn on the display prior to removing the charging cable from the device, this fixes the problem with the device draining while in sleep mode. I have done it for several days now, and there is no battery loss when not using the device. Could you try it and provide any feedback as to if it is working for you.

 

[sae160]

The 1st attached screen shot is the problem I am speaking of. Does not appear to be wakelock related. It took me a while to get a cycle like this (the undesirable discharge cycles don't always happen) so maybe the previous poster is on to something. A more expected sleep discharge can be seen in the second screen shot (ignoring the awake time as i was streaming Netflix via chromecast). I will continue to monitor for patterns.

 

[ArcFlash]

Like I said above, try unplugging it with the screen on. Ever since I have done it, the tablet does not lose any battery life at all while in sleep.