Why not simply a one-way 110V fridge?

[dougbaty]

After reading many posts here detailing shortcoming of various makes, I am now contemplating building a campervan. After buying a van, I would have to buy lots of RV stuff.

Checking into refrigerators, I was stunned to see that a 2-way fridge cost 3X what a standard fridge cost at my local appliance store. ($250 for a 110V office sized fridge, $750 for a Dometic that runs on 12V & 110V). What is the downside of simply running a fridge on the inverter?

I can think of a couple negatives. (1) It may consume more power since I would always have the inverter turned on as well as inverter efficiency losses. (2) The inverter may make an annoying hum. (3) I would need to buy a higher capacity inverter.

On the plus side, besides much lower cost I would have a wider selection of high efficiency choices and easier service.
DougB

[booster]

There have been quite a few "dorm frig" conversions done over the years on various forums, with varying success.


Aside from needing the inverter running all the time, the 110v only frigs tend to be very much less efficient than the Danfoss compressor frigs that are DC native, so power use is quite high. Not as high as a 3 way frig on DC, but higher than a good DC native compressor frig.


There are also concerns about durability of units not designed to be bounced down the road. Some people have had problems with early failures and others have not, so not really a good history to go by on that.


I think you don't see many complaints about the 12v compressor frigs. It is the 3 way absorption frigs that have lots of shortcomings and problems. As long as the venting is done well, the compressor frigs have done very well, I think.


If a person were to be on shore power most of the time, a pure 110v frig would likely be just fine.

[Davydd]

My RV has the NovaKool 6.8 CF compressor two door refrigerator/freezer. It can run on 110v or 12v but is set up to run on 12v all the time.

[InterBlog]

Your question relates to your tolerance for failures.

My own tolerance for rig-related failures is extremely low. I am self-employed and my husband is full-time employed (not retired, limited time off) and I drive from Houston to northeastern Nova Scotia every year (due to time constraints, my husband flies at least one of the two ways). If I have a mission-critical failure on that trip, then the entire trip may end up scuttled and I wouldn't get another chance to do the trip until the following year. Therefore we invest very heavily in high-quality upgrades for the van, including an $1,100 Vitrifrigo marine-grade fridge which has the Danfoss compressor mentioned above.

In contrast, someone who is traveling more casually and who has time to spare and who can afford system failures... maybe they would want to roll the dice with a cheap dorm fridge.

[avanti]

I will join the chorus in favor of a Danfoss-based native 12vdc unit. They are quiet, effective, reliable and very energy-efficient. Well worth the cost, IMO.

BTW: They aren't really "2-way". They all run on native 12VDC. The ones that can also run on 120VAC simply have a built-in power converter and are thus less efficient on 120VAC. There is no advantage to running on 120VAC in a van even when plugged into shore power, assuming your van has an adequate converter/charger.

[gregmchugh]

It also depends on what size fridge works for you and whether you need a freezer section. Many van campers get by with a chest fridge running on 12v and while they are more expensive than a dorm fridge they are less expensive than a larger built in fridge and the good ones with a decent compressor are very reliable and efficient.

[InterBlog]

Originally Posted by avanti

... They all run on native 12VDC. The ones that can also run on 120VAC simply have a built-in power converter and are thus less efficient on 120VAC. There is no advantage to running on 120VAC in a van even when plugged into shore power, assuming your van has an adequate converter/charger.

Correct. Ours has a loose AC electrical plug dangling off the back of it, a plug that is not inserted into the adjacent outlet. There's no point, even if we are on shore power.

[BBQ]

.

Some Class A and travel trailers use household fridge.

But I don't think those RV have as much shakes and vibrations as a Class B.

[booster]

Add us to that also. When I ordered ours, I got the 12v only version.


I do think that if I were doing a DIY or a major renovation I would look at using one or maybe two rollout chest frigs. They are more efficient than the door type and likely would also be more convenient as long as they roll out well.

[PinIN]

For the OP,
I have a $120 3.5 cuft freezer chest, 120v, 95w. For $20 I installed a temp controller that turns the inverter on and off, maintains 32°-40°, uses about 1.5 amps during the on cycle.
2x100 panels, 2xGC2 FLA, no external charger.
Parked on a semi shaded driveway.
Poorly ventilated cargo van, internal temp 75°-95°
Been running for 2 weeks, no problems.

[booster]

Originally Posted by PinIN

For the OP,
I have a $120 3.5 cuft freezer chest, 120v, 95w. For $20 I installed a temp controller that turns the inverter on and off, maintains 32°-40°, uses about 1.5 amps during the on cycle.
2x100 panels, 2xGC2 FLA, no external charger.
Parked on a semi shaded driveway.
Poorly ventilated cargo van, internal temp 75°-95°
Been running for 2 weeks, no problems.

1.5 amps of 110v is something like 165 watts, and that will be taking about 15+ amps of DC when running through the inverter. That is 3X the DC amps that the Danfoss cooled compressor frigs and chest freezers use. Of course we don't know duty cycle on either, which makes the comparison tough, but that is a big power difference. Chest frigs and freezers don't lose much heat, so that would help if it isn't opened much.

[BBQ]

.

The Danfoss motor and compressor have extensive installations in marine applications.

Just a data point.

[PinIN]

Dug up the test,
interior van temp 88°,
around 2.5 gals of water bottles in freezer,
inverter and freezer on cycle is 00:07:14,
inverter and freezer off cycle is 01:41:02,
freezer data plate, 115v, .89 amps, 95 watts,
I'll let others do the math, but in my situation this is cheap and it works.

[booster]

I can certainly believe the duty cycle for an unopened chest cooler, as they are much better than the vertical door stuff. Running about 1/20th of the time at about 10 amps DC by the time the inverter runs. That would give you about 12ah per day of battery use.

[cruising7388]

Originally Posted by gregmchugh

It also depends on what size fridge works for you and whether you need a freezer section.

An RV fridge without a freezer violates the Constitution because the inability to grab an ice cream bar from your freezer while on the road is nothing short of cruel and unusual punishment.

[Bud]

Originally Posted by cruising7388

An RV fridge without a freezer violates the Constitution because the inability to grab an ice cream bar from your freezer while on the road is nothing short of cruel and unusual punishment.

Yes, but I think you meant Dove Bar.

Bud

[Davydd]

Originally Posted by cruising7388

An RV fridge without a freezer violates the Constitution because the inability to grab an ice cream bar from your freezer while on the road is nothing short of cruel and unusual punishment.

Ice cream bar? You can stuff those in the tiny freezers. I won’t settle for anything other than storing a half gallon container of ice cream and frozen pizzas.

[Roadtrek Adventuous RS1]

Originally Posted by dougbaty

After reading many posts here detailing shortcoming of various makes, I am now contemplating building a campervan. After buying a van, I would have to buy lots of RV stuff.

Checking into refrigerators, I was stunned to see that a 2-way fridge cost 3X what a standard fridge cost at my local appliance store. ($250 for a 110V office sized fridge, $750 for a Dometic that runs on 12V & 110V). What is the downside of simply running a fridge on the inverter?

I can think of a couple negatives. (1) It may consume more power since I would always have the inverter turned on as well as inverter efficiency losses. (2) The inverter may make an annoying hum. (3) I would need to buy a higher capacity inverter.

On the plus side, besides much lower cost I would have a wider selection of high efficiency choices and easier service.
DougB

Doug,

It's all about efficiency...and a propane refrigerator is extremely efficient...yes, it more susceptible to higher heat...we try to park in the shade or at least keep the refrigerator on the shady side... whenever we can.... but, propane lasts about a month and is NOT using any battery power...

Downside is yes...a 3 way refrigerator is extremely expensive.. mine would be about $1,500..

Are they worth it..you have to decide for yourself...we like to do some boon docking...and we like National Parks... there's no power in National Parks..for the most part...so, the propane refrigerator works for us....

You purchased an RV to go places...why would you want to create limitations for yourself?

[booster]

Originally Posted by Roadtrek Adventuous RS1

Doug,

It's all about efficiency...and a propane refrigerator is extremely efficient...yes, it more susceptible to higher heat...we try to park in the shade or at least keep the refrigerator on the shady side... whenever we can.... but, propane lasts about a month and is NOT using any battery power...

Downside is yes...a 3 way refrigerator is extremely expensive.. mine would be about $1,500..

Are they worth it..you have to decide for yourself...we like to do some boon docking...and we like National Parks... there's no power in National Parks..for the most part...so, the propane refrigerator works for us....

You purchased an RV to go places...why would you want to create limitations for yourself?

Absorption frigs are probably the least efficient refrigerator you can get. Sure, they work better on propane than on 110v or 12v, but that is only because you can get more heat out propane than you can out of either of the electric ways. All that heat goes out the chimney along with a little bit of the heat from the frig. On DC, they use 5 times the power of a compressor frig for really weak cooling capacity.



IMO, there are many more compromises with a 3way frig than an compressor version. Leveling, outside temperature, fumes, are just a few. At 100*F you won't keep food cool in almost all of them. About the only compromise with a compressor frig is making the necessary power availability changes, which are normally not all that much.


I don't think I have ever seen anyone go back to a 3 way once they had switched to a compressor frig.

[cruising7388]

Originally Posted by Roadtrek Adventuous RS1

Doug,

It's all about efficiency...and a propane refrigerator is extremely efficient...yes, it more susceptible to higher heat...we try to park in the shade or at least keep the refrigerator on the shady side... whenever we can.... but, propane lasts about a month and is NOT using any battery power...?

Some of the early generation of propane fridges were capable of operating without battery support, but that's not the case with the current generation which requires battery support for the gas valve, the control panel and the circuit board. While these are not heavy loads, without recharge, this battery drain will eventually shut down the fridge long before it runs out of propane.