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Ask Dave: Can I convert RV’s 2-way fridge to 3-way for safety on the road?

Dear Dave,
Can an RV’s 2-way refrigerator (electric/propane) be converted to a 3-way fridge, to be able to safely run it while traveling? I have a 2022 Winnebago Micro Minnie, 2225RL. Thank you. —Thomas

Dear Thomas,
First of all, I applaud you for researching the safe way to travel by having the propane cylinder shut off. I do not know of any kits or upgrades available to convert a refrigerator to a 3-way. Three-way means it will run on propane, 120-volt power, or 12-volt house battery power with a 12-volt heating element.

From the specification on the Winnebago website, the standard refrigerator for the Micro Minnie and your model was a 10.3 cu. ft., 12-volt compressor-driven refrigerator. The option was an 8 cu. ft., gas/electric model. I’m still a fan of the gas/electric. It is better suited for dry camping, even if you’re not boondocking for weeks on end, just like the option of using the LP for an overnight here and there. I would assume the 8 cu. ft. model fridge was installed at the time the dealer ordered it, as the 10.3 cu. ft. models were in short supply at the time.

Seminar attendees have also asked about converting the RV fridge

In several of my seminars I have gotten the same question. Some have even suggested just installing an inverter that would draw power from the house batteries and provide 120-volt power to the refrigerator and charge the house batteries from the tow vehicle alternator. Sounds interesting; however, I contacted my “go to” expert when it comes to anything electrical, Mike Sokol, and it’s not that simple.

Mike indicated your RV fridge would probably pull at least 600 watts, as his tests have shown, and possibly more when running. Yes, a 1500-watt inverter could handle it. However, your battery/batteries will not. Also, the engine alternator through the 7-pin adapter could not provide enough power to keep the batteries charged after about 1 hour. Even if you had 100 ah lithium batteries, they would discharge in one hour.

So, to answer your question, there is no simple or inexpensive way to upgrade or redesign your refrigerator to be powered by the tow vehicle charging system going down the road.

Other options

Mike suggested maybe swapping out the current refrigerator with a Dometic 12-volt model with Danfoss compressor. He has tested that and it only draws a small amount of 12-volt house battery power that could be replenished by the tow vehicle while driving. Check out his review here.

The only issue with the 12-volt model is you do not have the luxury of propane when dry camping, so you will need to find a way to recharge the battery/batteries. According to the Winnebago website, your rig should have had a 190-watt solar panel and 30-amp charge controller standard. You will need to do some calculation on what size battery you have and what other items might be running. But you have a good foundation for using solar power to recharge your batteries when dry camping. You may need to add another panel. I would suggest looking at a portable model so you can park the rig in the shade and put the portable out in the sun. You rig also came with a plug-in charge port mounted to the side of the rig just for these.

Another option is to shut the refrigerator off and shut the valve off at your DOT cylinder. This suggestion typically gets quite a few comments. However, I did tests on both Norcold and Dometic and brought the unit down to 34 degrees. I used a remote thermometer to see what temps occurred. Over a 6-hour period, they were both at 40 degrees. Plus, it was about 90 degrees inside the rig.

Of course, this was without opening the door and with a little help. I put two 5-pound bags of ice in the freezer and some already cold food items inside. You will not be able to cool the unit down to 34 and put warm items inside and expect the same results.

This was a Norcold. The Dometic actually performed better as we had a 9v circulating fan inside it.

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

Read more from Dave here

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Joe Honermann
4 months ago

The answer is installing a one pound bottle propane, it should last at least 8 hours and if your skilled it can be installed in the cavity that is exposed for venting behind the refridge, if there would be a leak it less than 16 ounces, much better than 12 gallons.

Hakker
4 months ago

I would still like to know how you drive all day in the summer with the refrigerator turned off and not have everything spoil. I usually travel with the propane on for the fridge. Last summer after reading all the concerns, we packed and precooled the fridge to 28°(freezer 8°) and headed for Kansas. Temps hit 105° and when we stopped that evening it was 64° in the fridge and 38° in the freezer (124° in the trailer). For us the propane stays on from now on. BTW temps were checked with digital thermometers in both fridge and freezer.

Joe
4 months ago

Back in the day when I had a 2 way refrigerator in my previous motorhome I shut it off while traveling. We typically drove no more than 5 hours and never had an issue with the frozen food thawing out. Not sure what would happen in a tag behind or 5th wheel without some cooling to the cabin like our dash AC running to help cool the area.

Brad Teubner
4 months ago

Takes about 25A of DC to run our Norcold 1095 fridge from the inverter when the fridge is on. I do not know the duty cycle.

Ron Seidl P.E.
4 months ago

I tested the amp draw on my Dometic refrigerator and got 340 amps for the ac draw. This means a small invertor could power it on the road if only for a few hours.

Joe
4 months ago
Reply to  Ron Seidl P.E.

340 amp draw? I think you missed a decimal point. 340 amp draw would require a 600 AWG cable that is about the diameter of your thumb or more.

unless your talking about 340 amps over a given amount of time then that’s a different story.

Tommy Molnar
4 months ago

Last year on our annual trip(s) to and from Houston from Reno, the 90°+ heat during the day prompted me to try running the fridge on the 120ac using our inverter and drawing power from our two 100 amp/hour Lithium batteries. It definitely drew some power but the 700 watts of solar on the roof didn’t let the batteries get below 85%. We ‘overnighted’ in RV parks and plugged in. The batteries were fully charged in short order and worked great every day. Usually, we just turn off the fridge as Dave suggested but it was just too hot! I was thinking about going to a 12v compressor fridge but after talking to a couple of different RV techs, decided against it.

Bob p
4 months ago

I realize there is an inherent danger of towing with the gas on, however in the 43 years I’ve been towing I have never had a problem, that’s not to say I won’t the next time we go out. It would be interesting to know the facts about how many times a propane powered fridge has been the cause of an accident as compared to a possible ignorance of operator cause of an accident. It would seem to me the number of RVs running down the road with the gas on compared to the number of gas caused accidents is very small.

Tommy Molnar
4 months ago
Reply to  Bob p

I think most of the concern (for me anyhow) about running down the road with the fridge on is the problem of fueling up with an open flame in the area of the gas pump. How many folks are going to stop down the road prior to fueling to shut off the fridge, and then stop again after fueling to restart the fridge? At least that’s MY take on this topic.

Joe
4 months ago
Reply to  Tommy Molnar

👍👍👍👍👍

DAVE TELENKO
4 months ago

Gary very curious about the Micro Minnie and your model was a 10.3 cu. ft., 12-volt compressor-driven refrigerator as compared to the 12VDC Danfoss one that Mike suggested, as far as performance & wattage usage!
Snoopy


tom
4 months ago

We freeze water bottles and place in frig, both top and bottom. This keeps everything cold while on the road. No power or propane to the frig, just keep it closed. Works for us.

Warren G
4 months ago
Reply to  tom

Same here, Tom. We also have a small refrigerator fan on the bottom shelf which keeps the air circulation in the refrigerator, as well as thermometers in both the freezer and the refrigerator. Not a problem.

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