I've got lots of 9V LM voltage regulators. But not a danged single RV refrigerator control. My searches obviously took me to every doggone online refrigeration site except the "correct" one. Mexican reefers seem to use all line voltage thermostats. I'm going to connect the critter through a regulated power supply tonight and see how far down unregulated operation temperature droops. Do a few Delta T measurements to see just how lousy the insulation really is.
It's original incarnation was as a Kenmore. I am asssssssuming the Peltier device is still fully functional. Will find out tonight.
