In Support of a Household 120V Fridge in a Camper?

[wtwnnil]

Hi folks! I'm preparing for a custom build, and as I think through the options of which fridge to use, I'm considering going with a regular household fridge (like a dorm-style mini fridge). My main reason is the $1000+ price difference to get a comparable size front-loading 12V (like a Dometic, etc.).🤑😵

I've looked around online, and I can't find much information on this, other than about the extra power draw from using an inverter. I'm familiar with the argument about power consumption. It forces you to keep an inverter (pure sine wave) running constantly, so it's less efficient than drawing directly off the 12v batteries. My understanding is that the accumulated power consumption will be negligible. Please correct me if I'm wrong!

What I'm most interested in is the actual viability of using a fridge in a camper van, when these models of fridge seem to be incapable of being moved! Home fridges need to settle for multiple hours after moving before you can run them, to allow the compressor oil to settle. With that in mind, what are the implications of mechanical damage to a household 120V fridge if you're driving around with it? Furthermore, does it matter if it's running or turned off while driving? And, finally, what about using it on an angle, as I believe compressor fridges are slightly more resistant to being used on an angle in comparison to absorption 3-way fridges?

Please, any thoughts are greatly appreciated!😀

 

[calicamper]

This is one reason you see big $ rigs running 24v or even today 48v secondary power systems because its more efficient load wise to power inverters with 24-48v sources to get 120v power to appliances etc.

12v to 120v inverters are really inefficient so its not ideal.

 

[Peter_n_Margaret]

Domestic fridges with inverter motors are becoming a common choice for RVs in Australia.
They are typically powered via a dedicated 12V/240V 300W PSW inverter and seem to survive well.
A recent discussion.....

Domestic fridge & dirt roads - Caravaners Forum - Since 2000

I am currently building a new expedition vehicle and purchased a second hand Samsung SR227MW for under AUD$200 for it.
Do not be tempted to use a small bar fridge. Their power consumption is too high.
Cheers,
Peter
OKA196 motorhome

 

[Dave in AZ]

Will Prowse at DIYMobile has a video where he recommends just using a dorm fridge. He does the calcs, cost etc. They usually have 100% no questions asked replacement warranty.

He says that for the internal volume, power consumption is the same.

He is considered to be one of the top mobile solar guys on internet.

 

[Peter_n_Margaret]

inverter does not have to run constantly.

Victron inverters (and possibly others) can be configured to go into a sleep mode when power is below a pre set level.
Cheers,
Peter
OKA196 motorhome

 

[wtwnnil]

Thanks, everyone, that's brilliant!

@Peter_n_Margaret, wonderful idea. Amazon has compact 300W PSW inverters for about $50 CAD. This could easily fit in an adjacent cupboard to the fridge. And I suppose this little inverter is its own separate unit from the big 3000W inverter I'd use in the rest of the vehicle. This way, it saves constantly powering on/off the 3000W inverter charger with the fan kicking on throughout the middle of the night.

@Verkstad, I can almost grasp what you're getting at, but I don't quite understand. Sounds like a smart idea, though! Perhaps if using a small inverter dedicated to the fridge, the need to wire a separate thermostat is negated?

I imagine that, from Will Prowse's video (thanks, @Dave in AZ!), movement isn't an issue. If it was indeed an issue, I feel as though Will would've mentioned that driving with a domestic fridge means you have to let it sit and level, etc. So that's great news.

And maybe I can put the money I save into buying mini-fridge-sized drinks to celebrate! 🥳🍻 Thanks, everyone!

 

[NatersXJ6]

I’m just guessing that you will end up over time finding a lot of broken fridges and broken “stuff” in the fridge due to the appliance not being designed to tolerate the multiple g-forces developed on rough roads (or even just normal potholes)…. However, the ability to easily swap and source anywhere might balance out financially.

 

[NatersXJ6]

Since the inverter runs constantly, at least the interior lightbulb will always work.

Every time I check it does!

 

[NatersXJ6]

If you go the “turn off inverter” route, you probably need to be sure you find a fridge with the older style knob based controls. I’m thinking that something digital would try to reset to defaults every time the power goes on or off.

 

[calicamper]

I’m just guessing that you will end up over time finding a lot of broken fridges and broken “stuff” in the fridge due to the appliance not being designed to tolerate the multiple g-forces developed on rough roads (or even just normal potholes)…. However, the ability to easily swap and source anywhere might balance out financially.

There is very little to no difference between house hold fridges and “RV” fridges except cost. Its kinda like buying stainless bolts at a marine shop they are 200% more than the hardware shop around the corner both shops buy from the same supplier😆.

 

[wtwnnil]

Great point that some modern 'digital' style fridges might reset. Maybe that's a good motivator to buy a more 'economical' (aka, cheaper) version that still uses a regular turn-knob (akin to analog ).

And an excellent point, too, that an RV fridge does seem to be better designed to hold stuff in. My old 3-way had 'tabs' in the shelving on the doors to stop stuff sliding around (although even then, stuff still fell!). Plus, that fridge had a locking door, so I'll have to manually add on some sort of simple latch (which should be simple enough).

@NatersXJ6 and @calicamper, I do have some concerns about the robustness of a household fridge to the wear and tear of being constantly rattled while driving. If their lifespan is anywhere comparable to an RV fridge, and there's good warranty coverage on them, I'm inclined to go with the household version (because I need to be pragmatic about limiting the cost of my build parts).

 

[JaSAn]

I have been running a 2.1 cu.in. 'dorm' fridge purchased from Home Depot (~$150) for 3 years with a Victron 750 VA PSW inverter (it has a sleep mode that draws ~ 0.1A). It works fine in temperatures up into the 90ºs; doesn't work well in temps under 45ºF. It has withstood miles of bad washboard and undulating two track. I will buy again when this one craps out.

Some things to consider:

You will have to fabricate a way to mount it securely; they are made to sit on a stationary floor.​

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You will need to fabricate a way to keep the door closed during travel.​

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The door shelf restraints don't hold things well during travel; another modification needed if you use them or put carefully sized items on the door.​

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My fridge has a large power surge on startup: a Bestek 500W PSW inverter would overload and shut down. I am using a Victron 750VA PSW inverter without issue (Do over: I'd get the 1000VA model). You will want to mount the inverter as close to the battery as possible to avoid a long run of thick cable (750VA is 63 amps at 12V).​

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You need airflow around the sides and top as the condenser(s?) are inside the skin of most units (mine specifies 2"). Which means you cannot add external insulation around the fridge.​

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Mine has a cheap thermostat that is not holding temp well at year 3. I will be replacing it this winter; they are not expensive on Amazon.​

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There is an ~7ºF thermal gradient between top and bottom of my fridge. I plan on adding a small muffin fan when changing the thermostat.​

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I use an indoor/outdoor thermometer to monitor inside the fridge temp.​

Hope this helps. I'll probably think of something while I take da beagle for a walk.

 

[jwiereng]

Check out the energy efficiency of the specific inverter you plan to use, a the specific current.

I have read ranges of in the mid 80%s

 

[Ramdough]

Just a comparison.

These two are the same size and almost the same design.

https://www.homedepot.com/p/Magic-C...erator-in-Platinum-Steel-HMDR1000ST/304897182

RV Refrigerator 10 Cubic Feet 12V Stainless Steel

RecPro has a wide variety of RV Products like furniture, baggage doors and blinds. Free Shipping on all items!

www.recpro.com

They look almost the same.

FYI…. The reason you are advised to let a fridge stand still before plugging it in relates to the oil flow. If you put a fridge on its side or tip it too long, the oil may move away from the compressor. By waiting, you are letting it flow back to the compressor before startup.

These guys use a standard fronds in their Unimog and have had good luck so far.

 

[Ramdough]

You could also buy something like this to retrofit to your house fridge to hold the doors shut.

GE RDL-GPV10 Refrigerator Door Latch Kit

GE Refrigerator Door Latch Kit is designed to fit the GE GPV10 Refrigerators. The kit comes with the latch and two screws.

www.campingworld.com

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