Hey all, just need to ask for advice. My iPhone 4 has been experiencing rather bad battery life after downloading iOS 4.2. Here's the stats. My iPhone's brightness level is 1/7 of total brightness, 3G enabled, wifi and bluetooth off, no active apps. I fully charged my phone, left it in sleep mode for 8 hours without using it at all, then when I checked, battery life had already fallen to 85%. Is there a problem with my battery life?