We reported that some users were finding iOS 8.2 a bit buggy one of those bugs is battery drain, there is a temporary solution which could help those that simply follow these steps and hopefully Apple will release 8.2.1 to permanently fix this problem.
Step 1: Launch the Settings app on your iPhone.
Step 2: Scroll down to Privacy and tap it.
Step 3: Look for the Motion & Fitness Option and select it.
Step 4: You should now see an option titled ‘Fitness Tracking,’ simply turn it ‘Off’ to disable your iPhone from tracking various fitness parameters.