Latitude D630 Battery Problem

Hi all,
I have a Latitude D630. The battery on my laptop around a week ago suddenly went down from 14% to 7% and now its going down from 44% to 7% suddenly.
A little history on the issue. About 5 months ago my battery was replaced under warranty suffering under the same issue. Last time my battery was replaced, the charge level kept falling suddenly in 2-3 weeks that the charge kept falling from 95% to 7% and in a week the battery went completely dead.
Now, I'm worried that this isnt just a one off issue because this happened to me earlier. Im sure the battery is going to be dead in 1-2 weeks. The Dell guys say that as the battery is out of warranty, there isnt anything they can do. I just want to diagnose the problem ( maybe with the charging system of the laptop) so that incase I buy a new battery this does not happen to me again. Because is India, a 9-cell battery costs a whopping 9600Rs (Around 225$). Is there anyone else who has this problem or is it just me?

Regards,
Karan

 

batteries generally lose a significant amount of their charge after a year, and by year 3 usually they're pretty much dead.

normal.