I was having problems with my iPhone 4 not charging to 100%. I took it to the Apple Store and they gave me a replacement. For the first couple days, the new phone charged to 100% overnight, but the following days, it would only charge to 93-97%. I have tried other chargers from family members who have the iPhone, a restore, and have let the battery drain until it shuts off. Nothing has helped so I was wondering if this is a common problem? I am on OS 5.0.1 by the way.