Add-on
You can accomplish the 12V DC add-on two different ways. First if the cold plates in the boxes have a dual set of tubes you can use the second circuit to plumb in a 12V DC large condensing unit. This is normally a 1/2 h.p. unit as being cold plates it takes a larger capacity compressor to drive the expansion valves.The second alternative, and less expensive one, is to add a ColdMachine to the refrigerator side of the box. This will be a stand-alone system with its own thermostat and evaporator. That means it does not tie into the engine driven temperature control system or into the coldplates. It gives you the benefit of having refrigeration and small freezer section in refrigerator box with very little work to install.To get more information on this equipment go to www.kenyonmarine.com and click on refrigeration.