I'm sorry I don't know if I should post this but my battery is lasting like 6 hours. It sucks. I need help
I'm going to assume you've been using the phone awhile and had good battery life, so there can be a few causes for random massive battery drain on the S3. The most common seems to be the radio trying too hard to find a signal. So if you're in a low signal area a lot, that'll drain the battery much faster. I actually usually have to turn mobile data off when I'm at work because it'll drain 30% in an hour or two. Otherwise it's 2-3% an hour. This issue CAN come out of nowhere too. Even if Gsam says otherwise, it might be worth turning mobile data off for a day to see if it makes a difference....you might be surprised. Also when you look at System wakelock, is there a main process listed? It might be an app that's secretly keeping your phone awake for whatever reason.
For several of those problems, including the radio or random apps, I've read battery saving apps can be a big help, maybe even fixing it completely. I've experienced this and it sucks so IMO, anything's worth a shot!
I've found reducing the number of background tasks improves battery life and makes my S3 run snappier in every way. I'm currently very satisfied with background tasks limited at 2. It's done in developer settings. Cheers :-)
Sent from my Nexus 7 using Droid Forums
Well the thing is limiting background tasks is a good way to help conserve battery.
However, almost 60% in 6 hours with normal use is not normal in any circumstance. This is called massive battery drain, not trouble with battery life. There is definitely an underlying issue here, and you can turn your brightness all the way down and limit as many tasks as you want and it will probably drain just as fast. It's annoying as hell, but can be fixed....usually.