I updated my Lumia 925 to Lumia Black last week and I 've been disappointed with the battery life. The previous version Amber was great which provided me one day and a half with various tasks like messaging, browsing a bit. I optimized the every setting advised for sake of battery life and was eager to see improvement in battery life brought about by Lumia Black. However, battery can slope down from 100% to 70% in stand by mode for 4 hours. I 've been suffering from this a week and 've not seen any improvement. I 'm now less frequently using my phone like before, but I can hardly reach 1 day of battery life. I 'm considering a hard reset. Can anyone give me an advice?