Just to stir some water here.... I have original Nikon grip. Last time I charged my two batteries was mid-December. I was invited to take some pictures of Christmas recital. I took just shy of 100 images that night. Few days back I was testing a lens and took another 40 images or so. Today I decided to charge a battery before tomorrow's session and looked at the battery display - main battery in camera - 90% and battery in the grip is 78%. So self-discharge of the battery is 10% over period of 1.5 months. Anything over that is the third party grip or bad connection between the grip and the camera.