the upper pin is negativ and the pin at the bottom ist positiv. In my battery holder I use only rechargeable AA batteries (1,2V each for a total of 7,2V- Thats the Voltage the Camera needs). But I´ve got a Question by myself:
On the side of the GX680 where the battery pack fits in is in the middle a little pin; it seems to be a kind of switch. I´ve got two battery packs: one with a hole so that the pin is not pressed down and the other one will press the switch down... does anybody knows what this pin is for???