If you are in a weak signal area, an interior office with floors above you, for example, then your phone will have to operate at a higher power level. BBM continuously polls to see if you have a new message. That keeps your phone operating at a high power level and inevitably drains the battery.
I have two batteries with my Bold 9650, both purchased in January 2011 when I got the phone. The first one normally dies by 5pm or so and I switch to the second one. I recharge them both at night. My advice would be for you to get a spare battery.
I always make sure I don't have anything running in the background (not even GPS or bluetooth- only turn those on when I need them). I use what I use then exit the application. I also use an extended battery (2600). I charged my phone last night and won't need to again until Sunday night.
I went back to my bold for a few days from samsung epic, and the battery surprised me, either I am using my phone more now, or this battery is no good, could not go a single day without a charge.
