Help with choosing proper converter amperage

Just clamp a 150W inverter to your batteries and run an extension cable to the TV. Would I do it that way? Nope, but what I do does not matter and this will give you quiet TV watching. On the converter end, if you're making it right now, just replace what you have with the same. Maybe add an extra battery if you're just barely making through the 4-5 day trip.