Here's what solved all my battery issues and I tried everything. Fully charge battery and perform factory reset. The battery monitor may not be calibrated properly and this should assure it is. Now, be careful. Factory reset doesn't always work correctly. You can get the spinning gears for hours. Read the "flash 920 explained" thread before you attempt. You could brick your phone. Mine stuck on gears screen for 8hrs and I finally had to manually flash rom. There is a video and I suggest you watch it before you try. Also check out the other battery threads. There are many and they have more solutions on battery life and which apps have issues running on WP8. I've had two phones since launch and my battery life sucked pre and post Portico update. Factory reset, removed trouble apps and shutdown apps that didn't need to be running in background and my battery life is good enough now. And make sure you are using the Nokia charger. Its rated 1.3A if I remember right. Anything less won't charge phone fully.