Percentage of battery left doesn't show up right

[Maverick2k4]

Hey Guys,

I tried searching for this question but it didn't show up so my apologies if this question have been asked already.

I bought the Touch Pro from Best Buy couple weeks back and love the phone.

However percentage of the battery left always shows up like 31% or 35% or maximum 41% even after a full night charge.

Can anyone tell me how can I fix this issue?

Thanks a lot