actually no
the energy needed for the kers under current regs (or maybe it was the earlier slightly less hp regs... doesnt matter really) works out to about the size of a largeish laptop battery (granted you probably need a larger number than the strictly necessary amount of batteries to achieve the 80hp power output)
also being lithium based (i believe most teams use life chemistry) the batteries can be rather small
anway the battery should be smaller than you average rubbish lead car battery