I've just bought a Panasonic G3 second-hand off Ebay. It's only a few months old but it's battery life is terrible. I've tried it with the original Panasonic battery and a generic replacement and both give poor results. I got an hour's worth of video use out of the Panasonic battery after it had been fully charged and less than 100 shots out of the generic battery. I know the battery life of these batteries is supposed to be poor but could there be something wrong with the camera? If so, what?