I was getting very short battery life from my blackberry even after replacing the battery. After upgrading to blackberry software version 4.6 the battery life seems to be lasting much longer.  Before the upgrade my bettery would not last thorugh the night if it was not plugged in. Last night I forgot to charge it and I expected to see it dead as usual, but to my surprise it had practically a full charge and continued to have full battery the whole day. I am not sure if the new software has better battery management but I am very happy with my blackberry now that it is working as it should.