Thought I would answer another post, but thought this might be better in its own thread.
I found a couple of devices that can improve the functionality of your refrigerator, to get the best functionality out of it you really need get both of the two devices. These are offered at Coastal Climate Control
The first is the Guardian, compressor speed control and digital thermostat
This provides a digital thermostat and thermometer with a manual compressor speed control. It gives you a a digital thermometer and a manual control for your refrigerator setting.
It also has an auto setting that you need to purchase the optional Merlin II, mini smart speed controller
This allows you to use the optional setting, you can set the temperature controller to a set temperature and it will pick the best and most efficient speed to run the compressor at.
Together these make a pretty good controller, I have found in extremely hot days with high inside temperatures it will still struggle to keep temperature at the set temperature.The bad thing is they are extremely proud of these devices and charge accordingly.
I am running this in combination with a CRUISE 130 Elegance
Isotherm makes a product called the Smart Energy Control
While it performs similar functions , it does not find the best compressor speed. The setting of the temperature is also done with small dip switches on the unit which mounts on the Danfoss Controller. Unfortunately you need to pull the refrigerator out to gain access to change the settings.