GH2: short battery life

Hi everybody!

My GH2 drains the battery after 50-75 shots in a real life usage
(LCD is on for about 1 -1.5 hours, about 20% of all shots taken with flash).
Not even close to 300 shots as promosed by specs.
Is smth. wrong with the battery, or is it really 'normal'?

Thanks for advise,
best,
Andrey.