How long should a Galaxy S3 battery last? My phone is brand new and today it was on standby for most of the day (it dropped 10% while being on standby for 3hrs), I only used the internet for about an hour and recieved one phone call. And my phone is almost dead! I have gps and bluetooth disabled, the screen as dim as it will go and don't have any instant notifications. I also don't have any new apps on the phone yet. My battery life says: screen 41% Adroid System 19% Adroid OS 12% Device Idle 6% Cell Standby 6% Internet 4% Maps 3% Phone 3% Messaging 2% Could I have a faulty battery?
I have an AT&T Galaxy SIII. I use BetterBatteryStats when I have battery issues. Lately I've been having problems with the calendar sync service keeping the phone awake. I cleared its data and resynced from scratch, and that helped, but a few hours ago I created a new calendar, and now it's going bonkers again.
Anyway, the best I've been able to get is about 3% per hour when not being actively used. I might have seen 2.5% one time, but that was a few months ago. Typically though, especially with this calendar sync problem, I see 4.5% per hour or worse.
So if your question is, "How long should the battery last?" my best answer from my experience is about 24-28 hours, considering an average 3% per hour drain while idle, and light usage. If you make a few long phone calls, that will, of course, drain it much faster.
But any apps that go haywire and cause excess wakelocks will wreck it quick. I love the freedom of Android compared to iOS, but I really want more control over apps background behavior. Android 4.3 may provide this, but who knows if the SIII will ever get it.