Why does my phone randomly shut off?
Yesterday, I installed a replacement battery in my iPhone 4S. The charge icon indicates that the battery is 100% charged. I removed the phone from the charger and left it on for 24 hours and it still shows a 100% charge. But, it has randomly shut off 3-4 times. Each time, I have to plug the charger back in before the phone will boot. There are no "low battery" warnings and the screen always shows the battery at 100%.