Wednesday, November 29, 2023


RV Electricity – Just Ask Mike (J.A.M.): Chiller? Cooler vs. refrigerator comparison

By Mike Sokol

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) with the subject line – JAM.

Dear Mike,
I recently bought a plug-in cooler and was really disappointed when I drove to my picnic spot a few hours away, and my meal was ruined. I thought this was a cooler, but it doesn’t get the temperature down like my RV or home refrigerator does. What gives? —Crystal

Dear Crystal,
Here’s where you made your mistake. You bought a “cooler” which relies on something called a Peltier Effect thermocouple to lower the ambient temperature by a fixed amount, say 30 degrees or so. Now, as long as your cooler is sitting in a reasonably cool spot with an ambient temperature of, say, 80 degrees it can keep the inside cool to a reasonable 50 degrees.

But if you put the cooler where the sun can beat down on it and the ambient temperature gets up to 100 degrees, it can still only do a 30-degree drop down to 70 degrees on the inside. That’s not cold enough for nearly anything needing refrigeration, so it’s no wonder your cold cuts turned into warm disappointments.

What you really need is a portable refrigerator/freezer that uses a real Danfoss 12-volt DC compressor with evaporator and condenser coils. And I just so happen to have a demo Vitrifrigo Vfree refrigerator/freezer that was sent to me a few weeks ago to review.

I haven’t had time to run a bunch of energy usage tests just yet (that’s happening in a few weeks), but I can tell you it’s an amazing piece of gear that makes me happy. Set it for 35 degrees F and it’s just the right temp to transport seafood. Set it to 0 degrees F and it will freeze a bucket of water into a block of ice overnight. And yes, I really like my beer cold as well.

I recently took the Vitrifrigo Vfree on two different road trips, the first one being a 1,000-mile drive for a video shoot. I packed it with a few of my favorite foot-long subs along with bottles of water and Bubly (from PepsiCo, not a typo) drinks, set the temp for 36 degrees (since I didn’t want to freeze my subs), plugged it into a 12-volt convenience outlet in my SUV, and I could hardly hear it running, even with the car engine off. And you can set a low-voltage cutoff so it won’t drain your battery when you’re away.

My second experiment was a crab run down to the Chesapeake Bay for my birthday crab feast. While I didn’t need to keep the crabs cold, I did want to keep them warm for my ride back, so I used my Igloo cooler in “hot” mode by reversing the power plug.

But I also took along the Vitrifrigo fridge to bring back fresh shrimp, scallops and crab meat. (Yes, I’m a blue crab junkie from Maryland.) This was great because I used the Igloo “warmer” to keep the blue crabs warm for the trip back, and kept the fresh seafood at a perfect 34 degrees F for the hour-and-a-half ride back home. And there’s no chance of water-logging your food or melted ice to drain.

Expect a full report on energy usage of this type of refrigerator in the next few weeks, but right now I’m in love with the utility of a portable refrigerator/freezer that can go wherever I go and allows me to go from chill to freeze at the touch of a button. And this would make a great upgrade for a small camper in need of a fridge capable of hold a few days’ worth of food. I highly recommend this technology for your next road trip, camping or otherwise.

For more about Vitrifrigo products please go HERE. And Dometic has now shipped me a 10 cu ft RV refrigerator with a 12-volt DC compressor, so expect more experimental data soon.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

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 For more info on Mike’s qualifications as an electrical expert, click here.
Join Mike’s popular and informative Facebook group.
And you don’t want to miss Mike’s webcasts on his YouTube channel.

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Bob p (@guest_85875)
3 years ago

Crystal didn’t read the instructions, if she had it clearly stated as you stated it will chill the inside 30 degrees cooler than the temperature around it. I used a Coleman cooler when I was driving truck, my wife would prepare my daily meals in Tupperware bowls and freeze them. When I left out for the week all my meals were placed in the bottom of the cooler. In trucks with a sleeper, the cab and sleeper are separated by a heavy vinyl curtain and sleeper and cab A/C temps can be controlled separately. Putting the cooler in the compartment for it and closing the curtain I could keep the sleeper at 60 degrees and the cooler would hold 30 degrees. When I went to bed I moved the cooler to the front passenger seat and turned the cab A/C to the coldest setting. Usually by Friday evening when I got the last meal out the food was ice cold but not frozen, but I had preserved my food for 5 1/2 days. I had a small 700 watt microwave that I heated my food with everyday.

Crowman (@guest_85871)
3 years ago

I bought an Engal refer/freezer that’s 12v/120 power 5 years ago and can tell you it’s the handiest item to have in camp. When we go to the coast we use it as a refrigerator for extra food and when I go hunting or fishing bring frozen foods since it will freeze down to 0 degree’s.

tom (@guest_85853)
3 years ago

The cooler is just that, a cooler. Mine works good for what I use it for, grocery runs of about 1 hour. Knowing the actual physics behind it, I do not expect it to go below 40 degrees from ambient temperature.
Be interesting to see the others.

Lance Boggs (@guest_85915)
3 years ago
Reply to  tom

This is the biggest of the line we offer. I was able to get it to -4 in Miami heat within an hour.

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