I have an older system which is driven by an engine driven compressor and it works just fine. Important to consider: box insulation, and don''t believe that it is easy to install yourself. The holding plates--especially freezer are huge but once it has been running for a while ie couple of days- it keeps things preety well frozen. I did not opt for the 12v unit in addition to the engine driven which was a mistake. Make sure you have room for the holding plate. Also I bought both a freezer plate and a refrigerator plate since I have two ice box compartments. I did not install the refrigerator plate but rather elected to use a spillover from the freezer compartment. Simply a flap at the bottom of the box which covers a 2" diameter hole between the two boxes and I can regulate the amount of cold air coming in to the refigerator box by opening and closing the flap. Normally I will start out with a few blocks of ice in the bottom of the refrigerator box just to lower the temperature. Usually That ice will remain frozen and assists in keeping things cool. Most of the repair parts, belts and filters are available from refrigeration supply houses and a lot cheaper than buying from Technautics. Their follow up and support is very good. I normally would run the compressor twice a day, but if the box is full and the contents are frozen substantially less time is required. Enjoy your ice cream!!