[PNW Fireguy]

if the two 12 volt batteries are the ones that came with your rig they may have about 100 amp hours between them of usable capacity. I am not too sure about the TV altenator being able to keep up with the draw on the batteries. I would recommend using 4 6V deep cycle batteries. Hook two each in series to produc e 12vdc and then connect those two strings in parallell to double the available amp hour capacity.