My Lumia 920 was draining its entire charge in just a few hours. See the photo!
What I did? Deleted all email accounts and re-inserted them anew by hand, set display brightness to minimum and dark. Then I have drained battery completely and charged it at least 12-16 hours a few times. That has changed the battery life from the very bad to the very good battery life. See the second photo!
Seem to indicate the issues will clear up if you condition the battery with full discharges and charges.
Have a good Lumia day!
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