I just bought a second hand Samsung Galaxy Portal, and it's a great phone and works fine, but the battery is dead 12 hours after a full charge. I had a task killer installed at first but I removed it after reading about how it drains the battery, so I'm wondering what else it could be? I know it might just be an old battery that's lost it's will to hold charge, but what can I check on the phone before I have to splash out on a battery or take the phone back? I know it has some decent tools for monitoring battery usage so what should I be looking for? Thanks.