My 822 has generally had good to great battery life, but the last day or so, it started running the battery at a consistent 10%+ per hour. I was stumped and started killing off background processes, checking my signal, and doing other minor tips to no avail. Then I realized that I had gotten Chronos Calendar up and running the other day. Since I also use Simple Calendar, and like it, I decided to uninstall Chronos and the rate dropped below 6% (currently at 3% with a news app running). My best advice is to suspect one of two things causing large battery drains: 1) an app that is not efficient when installed and running background tasks and/or 2) poor signal strength causing constant tower hand shaking. If you have excellent signal strength, then start removing your apps until you find the culprit.