Sure. It must be a DC machine. Turn the amperage setting down to about minimum. Be careful of the polarity of your leads. When using "Reverse Polarity", electrode is Positive.
The jaws don't open wide on electrode holders, so C-clamp a small scrap of metal to the positive terminal of your batteries & attach the it. Then attach the ground lead (-), to the frame or bumper.
If anyone is concerned about the compatability of this procedure, check with a meter, the open circuit voltage of a comercial battery charger. Its about the same as a welder. Its best to charge batteries slow, with any charging system, so don't get carried away with the amperage.
Lee in Alaska