I noticed this happened on wednesday, my phone was in my pocket and it suddenly felt very hot and when I checked it I was surprised to see that battery life had somehow drained to 15% even though I had hardly used it except fro briefly checking my email and time (besides that it had just been sitting in my pocket). Prior to this, my battery life was pretty good and I usually had around 50%ish after a day of moderate usage. Currently it's been 5 hours after it's last charge and it's already down to 50%. I hardly used it today and it seems to drain incredibly quickly when not in use. Oddly I'm using it now to type this and it doesn't seem to drain as fast. I've updated to 5.0.1 and jailbroke it in January and it was fine so I don't think that's the reason why. And usually I don't turn on location services, I set the brightness at around half, don't turn on Bluetooth. I've tried recallibrating the battery to no avail. I did a hard reset once I noticed the phone felt hot and was at 15% on Wednesday but nothing seemed to come of it. The battery still drains very fast when not in use but doesn't get hot.