I've had the opportunity to watch a RW in action. It did ok with two 12v. batteries but when a third was added (the spare I brought from home), it did even better. The thing is, is there 4 vehicles in your group to possibly jump start each other?
I got the PPW in my own TJ and have used it on my own junk and have been on the trail or in camp to weld other peoples boo boos. It's a high frequency welder and it lays down a great bead @ 55 watts when the engine RPM is stepped up to achieve the 55 watts.
I've used the 120v. outlet to power single speed drills, angle grinders, blenders, a coffee maker and even a small microwave oven.
In battery charger mode, it will charge a dead 12v. to full juice in about 5 minutes at just above idle.
It was donated and installed at PPW in Yucca Valley, CA.
I made my own welding cables and battery charging cables.
And as mechanical things go, I've sent it back once to have bearings replaced, which I payed for and something that fried inside that was replaced free of charge. I also purchased a spare voltage reg. just to have in the tool box.