The 120 VAC power supply has an output of 14 VDC as noted right on it AND on the back of the TV. I have one in my kitchen as well so I just checked. These power supplies are not regulated and the voltage can swing quite a bite like Iggy said. The TV is on the house battery and I use Optima's. My batteries have a Voltage of 13.6 volts. Under powering the TV will not hurt it. If it did drop to 10 volts, the TV would turn off. If anyone is not comfortable doing it, then don't do it and use the 120 volt adaptor and use house power, a generator or even an inverter.