Hey guys! I have two camcorders. Cam #1: Power Supply: DC 7.2V (battery) Power Consumption: 7.4W Cam #2: Power Supply: DC 7.4V (battery) Power Consumption: Doesn't say :( - but should be the same roughly. How long can a "portable powerpack" with the following specs keep these camcorders running before running out of power?: Capacity: 1000VA / 500W Output: Nominal Voltage: 120V / 230V Battery Capacity: 12V / 9Ah x 1pc (think it says 1pc cause it's a UPC for computers?) Could someone please let me know the math on how to figure this out myself for future equations, too? Thanks so much!