Originally Posted by dave kitson
You can tell the camera how to use the batteries in the 'setup' menu under the 'select battery' option.
The camera will then use the batteries in the sequence you have set regardless of whether the grip is switched on. The off/on switch on the grip just enables the grip buttons and wheels.
dave
grip has to be on the on position for the batteries to be used on the grip
otherwise, no power if there is no battery on the body