Pocket Camera External Power Voltage

Site says 12-20V, is that for powering ANd charging or do you need 12v to power it?

Any battery/regulated ext. power source in that range. A Anton Bauer/Sony V mount battery (most common) are 14.5-16 VDC and go down to 12 as they discharge (same as a car battery) so input voltage to camera covers this range, and the camera converts it to the required voltage to run camera (DC-DC power supply). Otherwise unregulated batteries would not work which these and any ENG type camera that used this type battery to begin with.