Okay, had the iPhone 6 for a few months without issues. Updated to iOS 8.2 on Tuesday and last night I went to bed when around 65% battery. Woke up this morning and it was at 6%. Plugged it in at work and checked it about 30 mins later and it was 100% charged. Went to play football tonight and left it in my car with 68% charge. Returned an hour later and it was at 6% again. Got home and plugged it in and it straight away jumped up to 61% charge. Anyone else seen this behavior before? I'm not sure if it is a bug or a calibration issue or something more serious.