I was wondering about the extended battery. Have you run it dead, then fully charge it to let the phone know it's capacity?
With watchdog, you install it, then open it and use the default (not the aggressive) settings. It'll let you know if something is using a lot of cpu power, which in turn will run your battery down.
Can you list the top 5 apps listed in battery use when your phone has been idle? Like charge it before going to bed, reboot the phone (power off, then on) and let it sit idle while you sleep. We know using it will run down the battery, but I'm interested in what runs it down when it isn't being used.
Also, is wireless turned on? Do you use it? (if not, it should be off).