52% to 0% to 13% in one minute

i think i may have had capture data running or trying to save data or something (i am not sure if it was working very well) when my 13" mid 2009 macbook pro was at 52% battery life and i closed the case.

when i opened it about an hour and a half later it was total black screen and i had to manually start the machine whence it started up in the ye-old no battery power light grey screen with large white progress pinwheel mode showing 0% battery power - so i put it on power.

and then a second later the battery percent went from 0% to 13%.

is this normal?

p.s. the machine was in three weeks ago and got a new battery and a new logic board under applecare warranty.