12 Volt fridge

[gearhead]

I had a 3 way fridge in my 1978? Cabover. I was warned to never run it on 12 volt and I don't think I did. If my memory serves me correctly I did add an auxiliary battery under the hood for the camper. I don't recall any issues.
John I glanced at you attachments but didn't read them. My eyes and my head were wore out from driving.
Two long days on the road...from home to Ardmore OK and now just east of Emporia KS. Pretty nice COE campgrounds at Lake Melvern. My eyeballs are still bouncing from the roads. Tomorrow Knoxville Iowa.

[{tpc}]

The downside of the 12v fridge is if you have no way to connect to shore power prior to leaving for a trip. They get cold fast, that is for sure. But they suck the battery to nothing, in roughly 6 hours.

I'm not sure if you have a way to have the coach powered at home before a trip or if you plan to do so, but if you don't and your like me, packing it up 3-6 hours before your trip isn't always easy, especially if leaving in the early AM.

My temp workaround was to install a second battery in parallel, which seems to have at least doubled my time so far. This would allow me to pack say at 9 or 10 pm, if I am leaving at 7 or 8 am or earlier without the worry of a dead battery.

That said, I love my 12 volt fridge for how much stuff I can put in it, but I miss the flexibility of the propane since I can no longer park it in the driveway, or in front of my house but rather across the street.

[xrated]

Originally Posted by {tpc}

The downside of the 12v fridge is if you have no way to connect to shore power prior to leaving for a trip. They get cold fast, that is for sure. But they suck the battery to nothing, in roughly 6 hours.

I'm not sure if you have a way to have the coach powered at home before a trip or if you plan to do so, but if you don't and your like me, packing it up 3-6 hours before your trip isn't always easy, especially if leaving in the early AM.

My temp workaround was to install a second battery in parallel, which seems to have at least doubled my time so far. This would allow me to pack say at 9 or 10 pm, if I am leaving at 7 or 8 am or earlier without the worry of a dead battery.

That said, I love my 12 volt fridge for how much stuff I can put in it, but I miss the flexibility of the propane since I can no longer park it in the driveway, or in front of my house but rather across the street.

I don't have a 12V fridge, but I don't see why you couldn't connect to shore power while getting ready to leave on a trip. The two or three that I posted about earlier in this thread stated that when the compressor was running, it pulled 4 1/2 amps....which is 4.5 AH from the battery. Most single battery setups have around 100 AHs and if you only run it down to 50%, that's still 50 AHs which would roughly be 11 1/2 hours before you run the battery down......and that is with NO SHORE power supplying the converter. So if you have it hooked up to shore power and the converter trying to charge the battery and/or supplying some of the power needs for the fridge, I can't see it as being an issue.

I guess on a side note....I do have two Trojan T105 6volt batteries for a total of 225 AHs and of course cutting that down to only using 50% of the battery capacity, it is still 125 or so AHs. Plus, I'm plugged into a 50A shore power here at my house 24/7 unless I'm camping.

[rlh1957]

I had a 3-way fridge on one rig. All three modes worked well. LP & 12V worked great and neither sucked the juice. Never used the 12V on fridge more that a weekend so don't know how long it would last on battery snd never did the math to see what paper said.
They are efficient devices on LP, 12V or AC.

[{tpc}]

Originally Posted by xrated

I don't have a 12V fridge, but I don't see why you couldn't connect to shore power while getting ready to leave on a trip. The two or three that I posted about earlier in this thread stated that when the compressor was running, it pulled 4 1/2 amps....which is 4.5 AH from the battery. Most single battery setups have around 100 AHs and if you only run it down to 50%, that's still 50 AHs which would roughly be 11 1/2 hours before you run the battery down......and that is with NO SHORE power supplying the converter. So if you have it hooked up to shore power and the converter trying to charge the battery and/or supplying some of the power needs for the fridge, I can't see it as being an issue.

I guess on a side note....I do have two Trojan T105 6volt batteries for a total of 225 AHs and of course cutting that down to only using 50% of the battery capacity, it is still 125 or so AHs. Plus, I'm plugged into a 50A shore power here at my house 24/7 unless I'm camping.

For me that is the issue, I cannot park the coach in the driveway, and directly in front of my house it is a fire lane. So I can only park on the other side of the street and shore power would require an extension cord running across the street or trying to plug into someone elses house.

[xrated]

Originally Posted by {tpc}

For me that is the issue, I cannot park the coach in the driveway, and directly in front of my house it is a fire lane. So I can only park on the other side of the street and shore power would require an extension cord running across the street or trying to plug into someone elses house.

I gotcha now....I guess I missed that when I replied earlier. Running a cord across the street or using a neighbor's power could prove to be a no-no.

[Steve/]

So how much battery are you going to need to run a full size true 12v fridge for 3 day with no hook up or gen time or solar?

[JRTJH]

Originally Posted by Steve/

So how much battery are you going to need to run a full size true 12v fridge for 3 day with no hook up or gen time or solar?

There are WAY TOO MANY qualifiers to come up with any "one answer" for a question like that...

If it's 70F and parked in the shade or 90F in the sun.
How many times the refrigerator is opened and for how long.
What is in the refrigerator/how full it's packed.
What kind of batteries "hybrid discharged to 70% vs Deep cycle discharged to 50% vs Lithium discharged to 10%.
Condition of the batteries and their "performance"
What other battery drains are being used in the trailer, such as inverter use for TV's or fans, etc, incandescent vs LED lighting, furnace use, number of slides to be extended, electric vs manual awning and how often it's retracted when people leave the trailer, etc....

There is no "one answer for type or size of battery bank to "run a 12 volt compressor refrigerator for 72 hours"....

[Javi]

Originally Posted by Steve/

So how much battery are you going to need to run a full size true 12v fridge for 3 day with no hook up or gen time or solar?

I plan for the worst and hope for the best... Find out the maximum the fridge is going to use if the compressor ran the entire time and then buy batteries accordingly.. 100+ temps with no shade..

[xrated]

Originally Posted by JRTJH

There are WAY TOO MANY qualifiers to come up with any "one answer" for a question like that...

If it's 70F and parked in the shade or 90F in the sun.
How many times the refrigerator is opened and for how long.
What is in the refrigerator/how full it's packed.
What kind of batteries "hybrid discharged to 70% vs Deep cycle discharged to 50% vs Lithium discharged to 10%.
Condition of the batteries and their "performance"
What other battery drains are being used in the trailer, such as inverter use for TV's or fans, etc, incandescent vs LED lighting, furnace use, number of slides to be extended, electric vs manual awning and how often it's retracted when people leave the trailer, etc....

There is no "one answer for type or size of battery bank to "run a 12 volt compressor refrigerator for 72 hours"....

John, have you ever been called a "Party Pooper?"

[nitrohorse]

Originally Posted by Steve/

So how much battery are you going to need to run a full size true 12v fridge for 3 day with no hook up or gen time or solar?

John is correct, there a handful of variables when guesstimating battery life with a 12v appliance and it is almost impossible to give a definitive answer..

I have a 12v DC Danfoss compressor fridge, and I will tell you what kind of performance I experienced with my setup.
My fridge is rated at 50 watts per hour. That converts to 4.5 amps per hour. My fridge has roughly a 60% duty cycle at 70 degrees ambient temp, meaning that the compressor runs approximately 36 minutes every hour. That equates to 2.7 amps per hour. If you multiply that times 3 days (72 hours), you would consume 194 amps. Allowing for a 50% discharge on a typical wet cell battery system, you would need ~ 400 amps of battery to make it the 3 days. If you will experience higher ambient temps or frequent opening of the fridge door, I would use the full 4.5 amps per hour draw and go from there. I use a 200 watt Renogy suitcase solar system along with a small inverter genny and battery charger to keep the battery full. I would suggest you find a way to charge your battery as well.

[xrated]

Originally Posted by nitrohorse

John is correct, there a handful of variables when guesstimating battery life with a 12v appliance and it is almost impossible to give a definitive answer..

I have a 12v DC Danfoss compressor fridge, and I will tell you what kind of performance I experienced with my setup.
My fridge is rated at 50 watts per hour. That converts to 4.5 amps per hour. My fridge has roughly a 60% duty cycle at 70 degrees ambient temp, meaning that the compressor runs approximately 36 minutes every hour. That equates to 2.7 amps per hour. If you multiply that times 3 days (72 hours), you would consume 194 amps. Allowing for a 50% discharge on a typical wet cell battery system, you would need ~ 400 amps of battery to make it the 3 days. If you will experience higher ambient temps or frequent opening of the fridge door, I would use the full 4.5 amps per hour draw and go from there. I use a 200 watt Renogy suitcase solar system along with a small inverter genny and battery charger to keep the battery full. I would suggest you find a way to charge your battery as well.

Thank you for some real world numbers, that certainly helps put things in perspective.

[Mikelff]

Originally Posted by gearhead

Let's clarify exactly what type of refrigerator you have. The majority of RV's have a 110volt/propane refrigerator. It will run on 110volts from a campground, home, or generator source. If there is no 110volt source it will run on propane, but requires a 12 volt source for controls. The other type is what is commonly called a "residential" refrigerator. It runs on 110 volts from a campground pedestal, home outlet, or generator. It will run off 12 volt batteries through an inverter/converter that converts the 12 volt battery source to 110 volt.
However, there are some pure 12 volt refrigerators. They have a different style compressor, a Danforth. I haven't noticed any American RV major market manufacturer using them. Mostly European van conversions and a few American made truck campers.

FYI, Dometic now makes the 12volt compressor driven cooling RV refrigerator. You can order them installed from Keystone on new units. They work good, cool faster and colder temps. Faster recovery. They pull about 5-6 amps when compressor is running. For boondocking you will need a generator or solar with a good battery bank. Much more efficient than an absorption fridge. The best 12volt cooling units are from JC Refrigeration out of Indiana. They are an aftermarket supplier and offer a beefier cooling unit. Heavier gauge tubing. Hardly any welds, all connections are brazed. Fits your current fridge box. Comes with 3 year warranty and you can purchase an extend warranty for another 3 years. I was at their facility and had mine factory installed as I was on a trip up North anyway. Got the nickel tour and was impressed at their operation. They showed me the tubing Dometic uses and compared to theirs. Was noticeably thicker tubing. No inverter required for the 12v compressor units. There are also 120v units and those do require an inverter. These compressor units have become more popular and available the last couple years. IMO they are much better than residential fridge as they are built to take the vibration and bouncing of RV’s.

[Mikelff]

Originally Posted by xrated

I found a couple today, while searching the internet after reading this thread. Right now, I have an 18 cu ft. Norcold 2118 and that thing, to replace it is over $4000!! The biggest one I saw while looking today was a 17 cu ft and it was the 12VDC compressor style fridge....three door model....French door, with the freezer on the bottom and two doors up top for the fresh food area. Cost on that one was about $1800 and the compressor part of it only pulls about 4 to 4 1/2 amps....so in the 50Watt range. Separate controls for each area...the fresh food section and the freezer. Basically it is just like a residential unit only it is 12VDC. It was also made to be a free standing unit, so there has to be some clearance around the top and the sides. My Norcold compartment would be plenty big enough for it, but I would have to add some finish work (paneling or ???) to put it the original area and make it look finished.

I suspect, that the more popular they get, the larger sizes will start appearing too. I would love to have one, but as long as the Norcold that is in there works, I'll likely just keep it.....hmm!

Check out JC Refrigeration. You don't have to get rid of your fridge, just the cooling unit in back. jcrefrigeration.Com

[jxnbbl]

Putting this as a reply in a 12V fridge thread as some of this was mentioned in the a new 'ladder thread'.

We are looking at new trailers. One of the models that we are interested in somewhat proves the 2022 movement. It seems that the 12V 10cu ft fridge is the standard. But this lines up with a 200 SolarFlex for the unit.

Being new to 'Rving' this year, I had to wrap my head around a elec/propane fridge (really 12v converted down from 110/propane) now a 12V fridge that would run constantly (unless turned off at the breaker).

In terms of use, if we purchase this unit, we would not change our habits...we can live without AC when not with an electrical hookup (campground/generator) but spend a night or two with minimal heat, propane HW, propane fridge). We are always limited with graywater dumping.

So the question at hand is will the 200 W solar option be enough to charge the battery use or if I go down this path should I add dual AGM batteries for storage. I do intend to add an inverter mainly to just run the TV and internet without a generator....although we may read/play cards we occasionally run a generator to basically watch tv or do some quick work....which to me is a waste. Additionally I could price out an expansion to the 400W option

Comments/recommendations?

[JRTJH]

You'll get opinions "all over the field" about inverter selection and which is "best"....

By that, I don't mean brand (buy what you like with the features you want)..

What I mean is inverter size. There are two "schools of thought" on inverters. One is a "large size inverter to power everything or select plugs that can be used for anything".... The other is individual, smaller inverters, selected to provide power to specific components....

With the larger inverters, "wasted power" becomes an issue. As an example, if you're watching TV on a 32" TV that's rated 105 watts and it's plugged into a 2000/4000 watt "whole house inverter, that inverter will be "using more battery power at idle than a 200 watt inverter, specifically intended to power the television....

What I'm getting to is the decision on how much "convenience" will cost you in wasted battery consumption with a larger inverter that's not being economically used "most of the time"....

Take a look at both options, one large inverter or several smaller ones, tailored to your specific needs. Then "grow your system by determining how to implement your needs and calculate your battery selection based on your consumption.

Sometimes the "large, economy size" is not the best choice.... It's true in buying Wheaties that go stale and it's also true in installing an inverter in a trailer....

[Mikelff]

Originally Posted by jxnbbl

Putting this as a reply in a 12V fridge thread as some of this was mentioned in the a new 'ladder thread'.

We are looking at new trailers. One of the models that we are interested in somewhat proves the 2022 movement. It seems that the 12V 10cu ft fridge is the standard. But this lines up with a 200 SolarFlex for the unit.

Being new to 'Rving' this year, I had to wrap my head around a elec/propane fridge (really 12v converted down from 110/propane) now a 12V fridge that would run constantly (unless turned off at the breaker).

In terms of use, if we purchase this unit, we would not change our habits...we can live without AC when not with an electrical hookup (campground/generator) but spend a night or two with minimal heat, propane HW, propane fridge). We are always limited with graywater dumping.

So the question at hand is will the 200 W solar option be enough to charge the battery use or if I go down this path should I add dual AGM batteries for storage. I do intend to add an inverter mainly to just run the TV and internet without a generator....although we may read/play cards we occasionally run a generator to basically watch tv or do some quick work....which to me is a waste. Additionally I could price out an expansion to the 400W option

Comments/recommendations?

In addition to jtrjh recommendations, your battery choice will be just as important. I would recommend a couple of 6 volt golf cart type batteries which give you maximum amp hour storage. If you are going to do a lot of boon docking you should also consider a combination of solar and generator. Generator use mainly for battery charging back up if solar is your main power source. Your 12 v fridge will not run constantly once cold. It will cycle as needed. You need to put pencil to paper and figure out your power needs first and then you can determine what to use for those power needs. Will those power needs increase over time? How would you expand? How much weight will you be adding to your pin weight and does your TV have the capacity you need. Do you really want AGM batteries? They are more sensitive to damage from over discharges. Lead acid are more forgiving. Do you want lithium batteries? Lot’s to think about. Wish I could help more but I don’t boondock much so most of the time I’m hooked up to shore power.

[madridraidml]

How long will a 12 volt battery run a portable power station? If you're using a Lead Acid battery, you can only discharge to about 50% without causing damage and shortening battery life, so with Lead Acid batteries, you'll get about half that run time, or 12 to 25 hours.

[chuckster57]

Originally Posted by jxnbbl

Putting this as a reply in a 12V fridge thread as some of this was mentioned in the a new 'ladder thread'.

We are looking at new trailers. One of the models that we are interested in somewhat proves the 2022 movement. It seems that the 12V 10cu ft fridge is the standard. But this lines up with a 200 SolarFlex for the unit.

Being new to 'Rving' this year, I had to wrap my head around a elec/propane fridge (really 12v converted down from 110/propane) now a 12V fridge that would run constantly (unless turned off at the breaker).

In terms of use, if we purchase this unit, we would not change our habits...we can live without AC when not with an electrical hookup (campground/generator) but spend a night or two with minimal heat, propane HW, propane fridge). We are always limited with graywater dumping.

So the question at hand is will the 200 W solar option be enough to charge the battery use or if I go down this path should I add dual AGM batteries for storage. I do intend to add an inverter mainly to just run the TV and internet without a generator....although we may read/play cards we occasionally run a generator to basically watch tv or do some quick work....which to me is a waste. Additionally I could price out an expansion to the 400W option

Comments/recommendations?

An RV fridge is an “absorption” type, meaning it uses heat to boil a solution and as it travels down the coils it absorbs the heat from the freezer and fridge sections. It will have 2 different sources of heat- a 120VAC heating element or a propane flame. Usually you can choose which source you want.

A 12V fridge uses a 12VDC compressor just like a residential type of fridge that uses a 120VAC compressor.

The only “converted” fridge that I’m aware of is an RV type that has been retrofitted with a compressor type cooling unit and is considered “after market”. JC refrigeration is one such company and I can vouch for the quality of their product.

There are 3 way fridges that use a 12VDC heating element but it’s not that common