Why is my Galaxy S3 shutting off?

[Nathalya Carrillo]

why is my galaxy s3 shutting off? Battery or Phone?

I left my phone on standby 2 nights ago and when I woke up it had turned off. It would not turn on until I reattached the battery. It only stayed on for about 5 minutes though. And every time it turned on it displayed a lower battery percentage. I repeated this 3 more times with the same result. I thought it might have been an app I downloaded the day before that was draining the battery so I unintalled it. That seemed to have worked of about 4 hours until it shut off on me again and has continued doing so.

 

[Rukbat]

Re: why is my galaxy s3 shutting off? Battery or Phone?

The way to diagnose this is to use a known-good battery that's been fully charged and see how long the phone stays on.

Also check in Settings/General/Battery to see what's using most of the battery. (Press the graph and you'll get another screen. At the bottom of that screen is a line labeled Awake. It should be dark almost all the time except when you're using the phone - screen on, file downloading, something. If the phone is awake a lot, it uses a lot of battery. Install Greenify to keep the worst offenders from keeping the phone awake. Wakelock Detector will tell you what's keeping the phone awake for how long. If you're running KitKat and aren't rooted, see Wakelock with non-rooted KitKat. You don't have to do it every time, as in the FAQ - only when you want to see what's keeping the phone awake.)

(I had a similar problem this morning - phone off and battery at 1%. I had installed Lookout on a Samsung phone last night. I used Wakelock Detector and the battery information to determine that it was Lookout that was causing the problem on Samsung phones. [A notice about this on the site would have been nice.] So long Lookout until they fix it.)