So I have a gs3 (no root) and I've had it for about 3 months. It has recenltly been killing it's own battery every day. Sometimes I'll unplug it and it will immediately drop to 99. Today, I had it on standby for most of the day. Little to no use and it is at 20%. It says in the battery usage that android os and android system have used a combined 40% of my battery. I turned sync off a few days agi so I know that's not the issue. Any suggestions?