I recently got a One M8 from a friend. He had it for about a month and he says there have been no battery problems. I reset the device and the battery life started sucking big time. Charging would take forever, it would drain really fast, and it was terrible. I called HTC and they said I need to re-calibrate the battery by shutting it down, letting it charge for 10 minutes, they holding down the volume and power buttons for 2 minutes. Now, charging is fixed, but it still drains fast. I unplugged it this morning and watched YouTube videos for a while and after 30 minutes I was down to 90%. Is this normal for this phone? Before I got the M8, I had a Lumia 1520, so I am kind of spoiled on battery life. Any help would be appreciated. Thanks in advance.