By Mike Sokol
Dometic 12-volt DC refrigerator testing
Back in BC (Before COVID) I made a few acquaintances in the Dometic refrigeration division, and they promised to send me a 10-cubic-foot 12-volt DC compressor refrigerator as part of my study on refrigerator power consumption. I had almost given up on a test unit, when I received a call from my local trucking company about delivery. True to their word, a DMC4101 refrigerator has arrived for review.
I’ll begin a full review of its operation and power consumption in a few weeks, but for grins I simply loaded up the freezer with a 50% mix of frozen and room temperature meats and veggies, put a few 6-packs of warm beer in the fridge, set it to 5 Snowflakes of cold (yes, that’s the max cooling setting), and connected it to a 12 volt battery. So it got very cold, very quickly.
Baby, it’s cold inside…
Here’s a few quick pictures of how cold it got, and how long it took. As you can see, the freezer section was able to get down to a chilly 12.7 degrees F with a fairly decent load of consumables. While that’s not exactly a deep freeze temp of below 0 degrees, it’s more than cold enough to keep meats and veggies frozen for weeks on end. My wife and son are both ServSafe certified for proper food handling in the kitchen and during catering, and they concur with my conclusions about safe freezer temperatures.
There’s more than just cold, baby…
But my neat little Bluetooth thermometer has a logging function so you see how long it took to take the plunge. As you can see, it started at an ambient temp of 69.8 degrees, then plummeted to a minimum of 1.8 degrees air temp in about 2 hours. It eventually settled in around 12 degrees as shown above. And you can see the normal temperature swings of the thermostat, which look right on target to me. (Update: It was at an average of 4 degrees F this morning)
Note this was from a warm-start in a 70 degree room. That is, I didn’t pre-chill the fridge as recommended. I just loaded the freezer with a 50/50 mix of frozen meat and veggies, set it to 5 Snowflakes, and turned on the power.
The obvious comparison
Compared to a 3-way propane fridge, this is pretty amazing. Yes, you’ll still need an additional way to recharge your RV batteries either from solar panels, a small generator or CarGenerator™, or possibly a Flux Capacitor (just kidding). But these 12-volt DC compressor refrigerators with a Danfoss compressor not only are way more efficient than their 120-volt AC counterparts, they don’t lose conversion power stepping 12-volts DC up to 120-volt AC though an inverter.
More detail in a few weeks…
I have several other tests that I need to get through first, but I’ll have a few reviews on this refrigerator next month.
In the meantime, let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.