I've had my iPhone 4 since launch and never really had any problems with it. But ever since I moved into this house where I get either no service or 1 bar of 3g service (2 at maximum) I noticed that my battery no longer charges to 100%. I charge it every night as I'm sleeping. It will only charge to the 93-96% mark. In fact, it will even decrease WHILE its on the charger! I thought that this was because the iPhone is straining to search for service, so I turned on airplane mode but I get the same problem. I am using my wall charger. Does it sound like I have a defective battery or is there a way to fix it?