The past three ROMs that I've used - Cyanogenmod 6.1, UD 2.4/5, and now BB 6.1 - my battery has behaved very erratically. There has been a lack of consistency in drain times; for example, one day I talked on it for nearly 3 hours (total, not all at once) and the screen was on for nearly 2 hours, yet the battery was only at 40% when I got home. The previous day, I talked for 15 minutes and only listened to [locally stored] music, yet the battery was at 20% after less time.
On top of this, about 65% of the time, during discharge it will skip 30%. Once it hits 20 and I plug it back up it is back up to 50% or 60% in a matter of minutes.
I'm not certain whether this is a device problem or it's just time for a new battery. Thoughts, suggestions, comments?