Probably 5+ years old, maybe. Vista was released in January 2007. Who used Vista, for more than a year or two? (smile). That machine didn't come close to the power savings of today's computers.

Putting that aside -- The conversion of Watts to Amps is governed by the equation Amps = Watts/Volts. So 47 watts at 120v = .39 amps 99 watts = .825 amps Multiply x 10 to approximate the load in amps at 12v So we're talking about a peak load of roughly 8 amps and typical run load of half that. Most newer laptops (with better power savings, including SSD drives and LED displays) will do better.