Guys, I orderescthe Aputure for my D7000, I tested it in the shop, and it showed that the battery is dead!! Few days later, they brought me another one, guess what, same error. Even, I tested with a fully charged lithium geniune Nikon battery, and with 6 rechargeable lithium enercell fully charged. Still shows the batteries as dead (one dash). I tried to power on the camera from the grip, but it didn't power the camera at all. Please advise.