RV vs residential refrigerator?

[RVcrazy]

We are on the fence about trading out our 10yr old Dometic for a Whirlpool residential refrigerator. Because of space in our floor plan, it looks like the only choice still made that small... It looks like it will consume our small kitchen, but could fit. I am concerned about fridge fires. We do have the recall fix done.

Is the fire hazard all because of the propane, or is it regardless of your power source in use? A repair person is talking about installing a fire suppression device that fits in the back of the refrigerator as a safety check if there should be a fire. Have any of you seen or used such a device? Our other option is to have the gas capped & jut use it on electricity.

If you have changed to a residential refrigerator, would you do it again? I am concerned about needing to keep the residential fridge within such tight temperature limits (55-90 or so). We RV, not really camp, and have had electricity every night except 1 in 3 years on the road.

We would appreciate your input. Thanks!

Will it make a difference when we are ready to sell, a + or a -?

[BFL13]

In our 5er, the absorption fridge has more like 2/3 time on 1/3 time off when outside is around 75F. I assume a res fridge would be similar for that cycling? Not clear what would be realistic in various situations. There are also other 12v draws in an RV that add up over a day to add to the inverter's draw running the fridge.

What's the scenario? People here who have a res fridge might have a better idea what to expect in that scenario than I would.

[otrfun]

BFL13 wrote:

otrfun wrote:
Assuming one was powering a residential fridge with an inverter that drew 12a (at 12vdc) when the compressor cycled, how long would it take to discharge a bank of four, GC2, 6-volt batteries from 12.7 to 12.2 volts, under a worst case, full-on, 100 percent duty-cycle?

50 percent of 440 = 220AH/12a = 18.33 hours, but that does not allow for Peukert. The 20 hr rate for 440 is 22 amps not 12, so it should take longer than 18.33 hours. Looking at it another way, at 12a draw the capacity is more than 440 but I don't have the tables to show how much more.

Also ignoring "inverter creep" where its amps draw goes up as battery voltage falls, which will make average amp draw a little higher than 12 but do we need exact numbers here?

Thanks for breaking down the numbers, BFL13. Based on your calculations it would appear four GC2 batteries should last at least 24 hours (discharging from 12.7 to 12.2 volts) if the refrigerator's duty-cycle was reduced to a more realistic 35-50 percent. That's good to know. Thanks again!

[BFL13]

otrfun wrote:
Assuming one was powering a residential fridge with an inverter that drew 12a (at 12vdc) when the compressor cycled, how long would it take to discharge a bank of four, GC2, 6-volt batteries from 12.7 to 12.2 volts, under a worst case, full-on, 100 percent duty-cycle?

50% of 440 = 220AH/12a = 18.33 hours, but that does not allow for Peukert. The 20 hr rate for 440 is 22 amps not 12, so it should take longer than 18.33 hours. Looking at it another way, at 12a draw the capacity is more than 440 but I don't have the tables to show how much more.

Also ignoring "inverter creep" where its amps draw goes up as battery voltage falls, which will make average amp draw a little higher than 12 but do we need exact numbers here?

[otrfun]

Assuming one was powering a residential fridge with an inverter that drew 12a (at 12vdc) when the compressor cycled, how long would it take to discharge a bank of four, GC2, 6-volt batteries from 12.7 to 12.2 volts, under a worst case, full-on, 100 percent duty-cycle?

[MrWizard]

between midnight and 8AM ,one night light appox 7w and the fridge
no fans, no PC etc.

consumed power was 28 amphrs, according to the DC power meter
that amounts to 3.5 ampHr per hour and a combined ? duty cycle of aprox 35 percent

600MA for the 7w night light = 4.8ampHr
so 22.2 ampHrs for the fridge, 2.775 amphrs per hr or 27.75 percent duty cycle ?

if i'm doing the math correctly

this based on a 10amp draw while running, at the end of cycle its closer to 8.5~9 amps just before cycling off a tapered draw, including that would probably raise the duty cycle another 1 percent or so, not the amphrs, just the actual run time percent

of course a 12 hr overnight draw would calculate out approx 34 ampHrs for the fridge

i think i use more power with the PC and TV and other electronics

[MrWizard]

you could have sealed the back vent and roof vent

its what we do IN Our RVs

there was no reason to leave it open to outside temps especially in winter

[BFL13]

I thought it was about to be mentioned that a res fridge needs to be above 50F to work right, as in you can't keep your stick house beer fridge in the un-heated garage in winter.

In the truck camper, the res fridge we had would not keep proper temps in winter with most of it at outside temps with the back especially open to the weather with the big vent.

The front was inside, where it was warmer. Result was either the freezer would be ok but not the fridge down below or else no freezer, just right temps for the cooler fridge part. Was hard to pick what on the temp dial worked best. Mostly gave up on having a freezer but survived ok for a trip with the fridge part being right.

Have not yet used the 3-way ( only use 2) 7401L in winter, but hope that freezer vs fridge problem will not show up so much while on propane--we'll see!

In a "real" RV -not a TC 🙂 - with a 2-way or so fridge, it is more inside, so with the furnace on, most of res fridge is above 50F so that would not be a problem like what we had I suppose. At least we haven't had any of that in the 5er with the Norcold 2-way on propane.

[JimK-NY]

There are other choices besides a propane RV refrigerator and a residential refrigerator. Check out Nova Kool and some of the other companies that make energy efficient 12 volt compressor refrigerators. You don't need an inverter and the wattage is low enough to easily run it off the batteries and RV alternator while traveling. You can even run it entirely off the batteries for many hours without the RV running and without a hook up.

[TechWriter]

MrWizard wrote:

My fridge is on an outside wall, aren't all RV installed fridges on an outside wall
I use my awnings, and the fridge stays shaded

Putting down awnings is not always possible.

MrWizard wrote:

RV or electric makes no difference, if you park it in the sun , it will change the rate of cooling, residential just responds faster when you turn it up, because of the hot sun

Yeah, that's why I use cooling fans for my residential (and also for my old absorption fridge when I had it).

[MrWizard]

Absorption fridges are not fast cooling
But when properly installed work reasonably well

Problem is too many are improperly installed,

That is not the OPs problem and Not the topic of discussion

My fridge is on an outside wall, aren't all RV installed fridges on an outside wall
I use my awnings, and the fridge stays shaded
RV or electric makes no difference, if you park it in the sun , it will change the rate of cooling, residential just responds faster when you turn it up, because of the hot sun

[valhalla360]

Halmfamily wrote:
It's nice to have frozen ice cream and to be able to hold the fridge door open more than five seconds.

I must be doing something wrong. We've had 5 different propane units (including dometic) and always had frozen ice cream. Also don't have a timer for how long the door stays open.

If you are going to be on shorepower and limit travel to short runs, a household unit is viable but I wouldn't count on it being significantly safer and I certainly wouldn't replace a functional existing unit.

If you will be away from shorepower a lot, you can make a residential work but the hassle/cost factor goes up an order of magnitude.

Only real down side is when you first turn the fridge on, it does take a while to cool down.

[TechWriter]

MrWizard wrote:
Why are you worried about temp range

It's no different than living in a house or apartment

There is a difference.

In a house, your fridge is probably either up against an insulated wall or up against an insulated wall inside a cabinet.

In an RV, your fridge is probably in a sealed cabinet up against a thinly insulated wall.

I monitor my Whirlpool fridge temps, and this year I noticed the temps fluctuating when we stayed a month in a Gulf Coast campground. The sun would strike the RV's fridge wall most of the day. We could feel the heat inside even with the ACs on. It was even hotter in the space behind our Whirlpool.

From the Whirlpool manual: The preferred room temperature range for
optimum performance, which reduces electricity usage and
provides superior cooling, is between 60°F (15°C) and 90°F
(32°C).

So I installed some fans in the old fridge's roof vent to pull air from the inside of our RV, behind the fridge, and out the roof vent.

Seems to have solved the temperature fluctuations.

[MrWizard]

RVcrazy wrote:
We do not currently have an inverted, generator or solar panels. Would that change your opinion. We currently move fridge stuff to an ice chest for travel days over about 2 hours to keep food at a safe temperature. How long does the residential fridge keep under 40 if you are on the road without the solar etc? Thanks!

Now that is something that should have been mentioned in the very first post

There is a difference in say 3 hours when everything would ok
And 8 hours where the food would spend hours in a warm condition
On a hot day

My opinion would be install an inverter

Or just keep your RV fridge

While some people travel with no inverter
The options for keeping food chilled, vary from packing the fridge with blue ice cold packs, works ok
to loading the food in coolers for a full day travel,
Which I think is nuisance

[BFL13]

We went back to a propane fridge for the 1981 truck camper because it was not possible to keep the 120v fridge (replaced the busted original 3-way) running four days off-grid with not much sunshine. Got fed up with that. It might be easier in California! Love our new-to-us Dometic 7401L 🙂

Those 120v res fridges don't use much power, but they eat up lots of battery AH over a whole day. With four batts and 255w solar we just got by with lots of sunshine. No hope without the sun.

When the batts run down some in a day or two of no sun, now you have the inverter loaded voltage to keep above 11v (it varies by inverter model) problem or the inverter will shut down, so no fridge. That means you need more of a battery bank to keep the loaded voltage up, even though you would be still above 50% with just two batts but without much load.

It is all a big struggle with a smaller RV to find room for enough solar and battery bank to go off-grid without a propane fridge. You also need a generator and charger for that needed big battery bank to cart along too for when the sun doesn't shine. And gas for the gen.