The hatch battery is for the ignition - the receiver battery goes a little further back on the other side.
At this point I digress to a side project. I recently acquired a new phone (Galaxy Note 4, we're very happy together, thank you) and, as usual, an Otter Box Defender case to go with it. I don't use the Otter Box belt clip in the usual way - too big and bulky and I've always got pockets. But with a little ingenuity it makes a good tripod mount!
First step is to drill out the case so the camera and flash can "see" through. I start by marking the centre line.
Two pilot holes follow.
Off to the drill press, equipped with a 1" Forstner bit. The centre spur on the Forstner bit locates in the pilot hole.
