Fridge operation during travel?

[kdauto]

Originally Posted by Jerry Burks

I run our 18 cuft absorption fridge/freezer on battery and inverter to save the propane. That is however with a sizeable 300 Ah lithium battery. Since the inverter sucks about 40-60 amps from the battery to run the fridge (dependent on solar panel support), the battery is good for a 5-7 hour drive. I was surprised that this power consumption is quite constant, not cycling like a compressor fridge would do.

Before I installed the big battery, I used to run the fridge on propane while driving. Not too bad, but the propane consumption is not insignificant.

I think our fridge is around 9 cu feet or so. Propane consumption is very minimal. I ran it for weeks once between trips, and I calculated it would take 5 to 6 weeks in very hot weather to empty one 30lb propane cylinder. I'd be surprised if a newer 18 cu foot fridge would use more than 1.2 to 1.3 times that. I know ours has one or 2 tiny fans cooling the tubes outside, maybe that helps a lot.

[Old-Biscuit]

Originally Posted by Jerry Burks

I run our 18 cuft absorption fridge/freezer on battery and inverter to save the propane. That is however with a sizeable 300 Ah lithium battery. Since the inverter sucks about 40-60 amps from the battery to run the fridge (dependent on solar panel support), the battery is good for a 5-7 hour drive. I was surprised that this power consumption is quite constant, not cycling like a compressor fridge would do.

Before I installed the big battery, I used to run the fridge on propane while driving. Not too bad, but the propane consumption is not insignificant.

Norcold 2118 Polarmax 18 cu/ft fridge uses a 300btu rated burner
That is 3000btu PER HOUR of run time

1 gal of propane has 91,500btu
Not a big propane consumer.

[kdauto]

Originally Posted by Old-Biscuit

Norcold 2118 Polarmax 18 cu/ft fridge uses a 300btu rated burner
That is 3000btu PER HOUR of run time

1 gal of propane has 91,500btu
Not a big propane consumer.

300BTU burner or 3000BTU?

[Old-Biscuit]

Originally Posted by kdauto

300BTU burner or 3000BTU?

3000btu.....
missed one zero but did state 3000 also

300btu would be an old popup camper frdge with variable flame

[Jerry Burks]

Originally Posted by Old-Biscuit

Norcold 2118 Polarmax 18 cu/ft fridge uses a 300btu rated burner
That is 3000btu PER HOUR of run time

1 gal of propane has 91,500btu
Not a big propane consumer.

I agree, not a big consumer but nevertheless significant. Your numbers mean 30 hrs run time per gallon or maybe 240 hrs per 30 lbs cylinder. At 6 hours drive time a cylinder is good for 40 days of driving. On our last 6 week trip we would probably have to refill the bottle once for the fridge alone.
Not too bad but since I have that solar system I prefer to not use the propane for the fridge (except when boondocking for a couple of days). In that case the battery is reserved for other purposes.

[slotown]

Originally Posted by Soppy

I have a propane / electric RV fridge that I select electric only and run off an inverter while traveling . When I turn the ignition off the fridge shuts down. This prevents the fridge from running in an off level condition when I am stopped.

I like the sound of this idea. I usually travel with refrigerator in propane mode. I have 600w of solar and an inverter. But, I see a problem in my setup if, it’s cloudy I don’t think my alternator will keep up. Norcold 2118 is 5 amps AC, which takes 50 amps DC to convert. Probably would need a DC to DC converter, which wouldn’t be a bad idea. Then I could get rid of the gas station problem.

[Freebird2020]

Most new RVs that have a Residential Fridge include an inverter and 1 or 2 batteries and some include a 150 to 200 watt solar panel for traveling.

So when you unplug from electricity and plug into your truck, it will power the fridge until you get where you are going.

Having done it it the propane/12v way in a previous travel trailer, the above is so much nicer.

Cummins/Onan also has a new on-board 2500 Watt Inverter/Generator that runs on propane which would make it great for boondocking.

I don't boondock much so the propane fridge is not of interest.

[tlapera]

The devil's in the details ... so I need to leave the inverter on and the main power switch on while driving down the road to keep the 'frig cold? How can I tell if my inverter will take two batteries instead of just the one? Thanks for all the help gang!


Tony...2020 Coachmen Chapparal 35'

[bigchick]

Originally Posted by tlapera

The devil's in the details ... so I need to leave the inverter on and the main power switch on while driving down the road to keep the 'frig cold? How can I tell if my inverter will take two batteries instead of just the one? Thanks for all the help gang!


Tony...2020 Coachmen Chapparal 35'

if you have an inverter i'm assuming you have a residential refrigerator. yes the inverter needs to be on to supply 120 power for the refrigerator. if you are referring to the battery disconnect switch as the 'main power switch' it is highly probable that your inverter is wired directly to the batteries and dies not go through this switch. so whether it is on or off is irrelevant, but you need to confirm this.

the inverter draws power from your 12 volt battery bank. such a battery bank can consist of a single battery up to perhaps as many as eight batteries all interconnected. the key concept is that the battery bank supplies 12 volt power. the voltage it supplies is the same regardless of the number of batteries you have. additional batteries add capacity so the inverter will run longer but the inverter does not really know this. all it sees is 12 volt power and it will run using this power until the battery bank capacity is consumed.

[Yosemite77]

It’s common sense, but I’ll add this: To save power, be sure to get the the refrigerator cold before you leave. I’d suggest turning it on at least 24 hours in advance of departure.

[LAKnox]

Originally Posted by Yosemite77

It’s common sense, but I’ll add this: To save power, be sure to get the the refrigerator cold before you leave. I’d suggest turning it on at least 24 hours in advance of departure.

Works for =any= fridge. We also pre-chill everything that goes in. I also use a small battery fan to help circulate air throughout the box and, in my experience, I can raise the setting 1, so use less propane or electricity.

As for shutting my fridge off while traveling. Never have and have never had an issue. I also don't bother when fueling. I have a diesel truck and my fridges have always been on the curb side while I fuel on the street side, so it's 10-15' away from any pumps. I do know that there are some places where propane devices must be shut down prior to driving through, mostly tunnels.

Lyle

[wrvond]

The refrigerator in my new camper is a 10.3 cubic foot capacity 12 VDC only compressor unit. The camper comes with two batteries and a solar panel baseline. The base solar, along with the truck, is plenty to keep the batteries charged while driving.

[oscarvan]

Originally Posted by bigchick

if you have an inverter i'm assuming you have a residential refrigerator. yes the inverter needs to be on to supply 120 power for the refrigerator. if you are referring to the battery disconnect switch as the 'main power switch' it is highly probable that your inverter is wired directly to the batteries and dies not go through this switch. so whether it is on or off is irrelevant, but you need to confirm this.

the inverter draws power from your 12 volt battery bank. such a battery bank can consist of a single battery up to perhaps as many as eight batteries all interconnected. the key concept is that the battery bank supplies 12 volt power. the voltage it supplies is the same regardless of the number of batteries you have. additional batteries add capacity so the inverter will run longer but the inverter does not really know this. all it sees is 12 volt power and it will run using this power until the battery bank capacity is consumed.

This. 100%. I add the following:

Every RV I've owned/looked at in the last few years has had a residential refrigerator which is powered by inverter while traveling.

I have seen "Whole house inverters" that powered the fridge and select other outlets and users. On recent units I have also seen small dedicated inverters in combination with a transfer switch JUST for the fridge.