Cythrelo
I just want to make sure that 6V isn't going to kill my camera.
People will say that the USB specification is +5V, but that is actually irrelevant for our purpose.
The USB V+ is connected to a resistor that goes to the base of a dual-transistor switch before connecting to the DIGIC processor.
On my
A620, that resistor is 20K so the current is one quarter of a thousandth of an amp !
Assuming other cameras are similar, 6V is fine.
If you have access to a multimeter you can measure the resistance between the outer pins of the USB connector.
DO NOT user the audible continuity range of the meter !
David