I Thawed So

This is a follow up to:
http://72land-n-sea.blogspot.com/2011/11/recreational-refrigeration.html

I know the small chest freezer can easily maintain freezer temps but I wondered how low it could go. I set it to max cool and the thermometer said -40°. I thought, 'that can't be right, maybe it's reading in Celsius or something?' (look it up)

But the idea is to use the freezer as a cooler on the boat...freeze plastic bottles of water at home on the trailer, then unplug it and use it as a cooler while boating...and drink the cold water as the ice melts in the bottles. We haven't actually used it that way yet, but tests in the garage show it's an excellent idea - good for 3 or more days depending on how much water is frozen. This was done with the thermostat originally set at zero degrees - it may last much longer at -40 but I wonder if starting out at that temp wouldn't freeze my beer or other refrigerator stuff. I have a couple more months of Winter to figure that out even if it takes a case or two of brew.

But the next thought was what about using the freezer AS a refrigerator on longer cruises; we run the generator quite often for air conditioning anyway? But this would mean I'd need to get a different thermostat because the one on the freezer only goes as high as 10° and I'd like to be able to set it at 38 or 40°.

I wrote to the maker, Danby, with my idea, asking about a different thermostat. They would have nothing to do with me messing up the original innards of their freezer.

I bemoaned my lack of progress to my son-in-law and he said, "Just get a remote bulb, line thermostat."

After poking around on the internet I decided to take a chance on a $24 mini unit - includes shipping from China.

The China thermostat has no wires attached. To feed it 120 volts for it to work, I bought a cheap two wire extension cord and cut off the female end. I stripped the wires and secured them into the connectors on the back of the thermostat.

To control the power to the freezer power I bought another extension cord, this time a 3 wire job with the wires easily identifiable so I could pick out the hot wire.

I cut the hot wire, stripped the ends and secured them into the back of the thermostat.

The remote bulb had to be wired as well, to it's connectors at the back of the unit.

I plug the 3 wire extension cord into the wall and the freezer plug goes into the female end of the 3 wire cord. Now the thermostat can dictate when to send power to the freezer.

The thermostat reads in Celcius so I had to make myself a chart to know where to set it. I can set the temp where I want to freezer to kick in and how many degrees it should go before it cuts the power. This defines the working range of the freezer/refrigerator. I set it to kick on when the temp reaches a high of 38°F and it will stay on until the box is cooled to 34°. There's a light on the display that tells when the thermostat is passing cooling current. The thermostat is also capable of managing a heating circuit. The power, heating and cooling circuits are all separate so with 120 vac working power, this unit can be used to switch anything from low voltage dc to 240 vac as long as it's within the working power range.

This rig is the cat's pajamas. It's so satisfying when things come together like this. Next is a timer to see what the compressor run time is to bring the temp down to 34° after opening the top to get out a beer...this will take research well into the summer for accurate results.