Is A/C power necessary for refrigerator?

[sean2a]

Greetings all, I am in the process of ordering a new Escape 17B and one thing I am looking into is deleting the standard 3 way fridge and finding a compressor fridge to put in (deletion offered as option but not any compressor fridge options for this model), along with a beefy solar/ battery setup.

In doing this research for these fridges, I've noticed they come in D/C only and also both A/C -D/C varieties. My question is, if I have a battery charger as all RV's would, is it necessary to have an A/C mode for my fridge? I'm sure the battery charger would keep the batteries topped at a higher input than the fridge would draw if I was connected to shore power. Though my thinking was also perhaps it would wear down the batteries faster to always be cycling that 2-3 amp draw as opposed to giving them more of a break with A/C when on shore power.

Note, I did check around but couldn't find an answer to this question, so apologies if it's already been discussed.

[Jon Vermilye]

Originally Posted by sean2a

Greetings all, I am in the process of ordering a new Escape 17B and one thing I am looking into is deleting the standard 3 way fridge and finding a compressor fridge to put in (deletion offered as option but not any compressor fridge options for this model), along with a beefy solar/ battery setup.

In doing this research for these fridges, I've noticed they come in D/C only and also both A/C -D/C varieties. My question is, if I have a battery charger as all RV's would, is it necessary to have an A/C mode for my fridge? I'm sure the battery charger would keep the batteries topped at a higher input than the fridge would draw if I was connected to shore power. Though my thinking was also perhaps it would wear down the batteries faster to always be cycling that 2-3 amp draw as opposed to giving them more of a break with A/C when on shore power.

Note, I did check around but couldn't find an answer to this question, so apologies if it's already been discussed.

When plugged into a 120V AC power source, your converter (charger) will both charge the battery AND supply the 12V DC necessary to run the refrigerator. The only time you will discharge the battery is when you are not connected to an AC source.

[Raspy]

Sean,

I highly recommend the compressor fridge. And I don't see any reason to ever run a compressor fridge on AC in a trailer. That would involve either being plugged in, or running the inverter from the batteries, and then using AC to run the fridge. Plugging in automatically charges the batteries, which then run the fridge. It's all seamless.

You'll always have batteries and they can be charged from solar, your tow vehicle or from shore power. There should not be a time when you don't have DC available. And if you are charging from solar, no other fuels are used.

Compressor fridges are the same as household fridges in that they cool down fast, are reliable, and work the same regardless of the weather.

This will not wear your batteries out. When plugged into shore power, the charger carries all DC loads by keeping the batteries at a specific voltage during a float charge. When unplugged, the solar tries to do the same. When not charging, lead acid/AGM batteries should not be discharged below 50%. If you go with lithiums, you can discharge them much farther and they can be recharged thousands of times.

[sean2a]

Originally Posted by Raspy

Sean,

I highly recommend the compressor fridge. And I don't see any reason to ever run a compressor fridge on AC in a trailer. That would involve either being plugged in, or running the inverter from the batteries, and then using AC to run the fridge. Plugging in automatically charges the batteries, which then run the fridge. It's all seamless.

You'll always have batteries and they can be charged from solar, your tow vehicle or from shore power. There should not be a time when you don't have DC available. And if you are charging from solar, no other fuels are used.

Compressor fridges are the same as household fridges in that they cool down fast, are reliable, and work the same regardless of the weather.

This will not wear your batteries out. When plugged into shore power, the charger carries all DC loads by keeping the batteries at a specific voltage during a float charge. When unplugged, the solar tries to do the same. When not charging, lead acid/AGM batteries should not be discharged below 50%. If you go with lithiums, you can discharge them much farther and they can be recharged thousands of times.

Thanks for detailed explanation Raspy. I guess then the only time I would ever be without batteries is if the battery charger or batteries themselves failed but that would probably be unlikely. Only other purpose I could think of then of the dual power source is if I for some reason removed the fridge and wanted to use it in a residential setting but I could probably found an adaptor for that purpose. So this clears up any reservation I had.

Thanks again!

[Civilguy]

Originally Posted by Raspy

Compressor fridges are the same as household fridges in that they cool down fast, are reliable, and work the same regardless of the weather.

Sometimes I just hate that we can't say these things about absorption fridges, sometimes not even one out of three...

We are going to do some travel that will include a loop through some high altitudes. I've found myself pondering how that might go, even to planning stored provisions that will not require refrigeration supplemented by more reliance on local sources. Second choice is to operate the fridge and/or our collapsible cooler as an icebox. The distant-third choice is to take along our little compressor fridge freezer which is really bulky for the limited capacity that it offers. That would ensure that our mayonnaise does not die in vain!

[Civilguy]

Originally Posted by sean2a

Greetings all, I am in the process of ordering a new Escape 17B and one thing I am looking into is deleting the standard 3 way fridge and finding a compressor fridge to put in (deletion offered as option but not any compressor fridge options for this model), along with a beefy solar/ battery setup.

It strikes me as possibly significant that Escape is not offering this as an option as they do on other trailers.

Do you have a handle on something that will readily fit the available space?

[Glenn Baglo]

You can also stop at a local butcher and pick up a prime rib steak, the local market for some fresh corn on the cob and new potatoes and at the local bakery for a fruit pie. Pick up a pint of ice cream and it will be just right for scooping onto the pie for desert.
That's not me in the pic.

[Civilguy]

Originally Posted by Glenn Baglo

You can also stop at a local butcher and pick up a prime rib steak, the local market for some fresh corn on the cob and new potatoes and at the local bakery for a fruit pie. Pick up a pint of ice cream and it will be just right for scooping onto the pie for desert.

Yes, we been known to do some things like that on occasion!

Fortunately we will be within reach of some sources of fresh food at the rocky mountain park we are headed to.

We are scheduled for a site inside the park without electric power, and I anticipate propane operation may be dodgy in the thin air up there.

[CalCop]

sean2a,
If you decide to go with the compressor fridge, buy the 12v model not the 12v/120v model. The control box on the fridge would convert the 120v into 12v. Don't ask me why they offer the 120v models.

[Raspy]

Originally Posted by Civilguy

Sometimes I just hate that we can't say these things about absorption fridges, sometimes not even one out of three...

We are going to do some travel that will include a loop through some high altitudes. I've found myself pondering how that might go, even to planning provisions that will not require refrigeration. Second choice is to operate the fridge and/or our collapsible cooler as an icebox. The distant-third choice is to take along our little compressor fridge freezer which is really bulky for the limited capacity that it offers.

I used to be so enamored with propane fridges. The idea of them and trying to figure them out was so interesting. Years ago I tried to make one work directly from the heat of thermal solar panels. Early ones that used no power at all were so nice in a very limited camper, after having ice. And I've mostly had good luck with them. But suddenly the compressor fridge is on the scene and I'm treating it just like the one in the house. It is always on and kept alive by solar charging the batteries. No more starting it up a day before leaving, watching the propane use, or finding it's too hot outside to work well, etc.

These new fridges, like lithium batteries are beginning to gain acceptance. Once I got on board, i knew I would never go back. Now, absorption fridges seem so outdated and un-interesting. Same with lead acid batteries.

I think the same thing is beginning to happen with the waterless toilets.

All of a sudden, the trailer is almost independent of grid power, while having lots of modern conveniences. Uses way less water. And has a modern reliable and relatively large fridge and freezer, just like home. All in a very compact trailer. It's liberating, more comfortable and allows longer stays out in interesting places.

[sean2a]

Originally Posted by Civilguy

It strikes me as possibly significant that Escape is not offering this as an option as they do on other trailers.

Do you have a handle on something that will readily fit the available space?

Yup I’m certain Nova Kool sells a 4.3 cu fridge that will fit in the 3.0 cu footprint that is setup for an absorption. They only just started offering compressor fridges in the other models in the past couple of years, though they are going with Norcold for those models and they don’t offer quite as good of a fit fridge for the space. I’m pretty sure they’ll start offering it in the 17 in the next couple years.

Biggest benefit in doing it at this stage is the ability to keep from cutting the two outside vents. I’ll have to make my own vent from the cabinet on the inside but that’s not a problem.

[sean2a]

Originally Posted by CalCop

sean2a,
If you decide to go with the compressor fridge, buy the 12v model not the 12v/120v model. The control box on the fridge would convert the 120v into 12v. Don't ask me why they offer the 120v models.

Thanks, I’m starting to wonder that myself!

[Civilguy]

Originally Posted by sean2a

Yup I’m certain Nova Kool sells a 4.3 cu fridge that will fit in the 3.0 cu footprint that is setup for an absorption.

Yes, it only makes sense that the compressor fridges would make units which could replace absorption units.

Originally Posted by sean2a

Biggest benefit in doing it at this stage is the ability to keep from cutting the two outside vents. I’ll have to make my own vent from the cabinet on the inside but that’s not a problem.

Before I read this, I used to idly wonder how the compressor fridge would work without venting to the exterior. After all, they are just pumping heat out of the fridge cabinet and into the RV’s interior.

Now I’m having one of those forehead-slap moments; the compressor fridges don’t need to vent all the heat that’s used to boil the ammonia solution, and only minimal amounts associated with the inefficiency of the compressor.

Having spent a great deal of time reading up on absorption fridges, and having subsequently implemented measures that greatly improved the operation of the one in our Casita, I am once again struck by my finely-tuned brain’s ability to get completely lost in the weeds sometimes.

[Civilguy]

Originally Posted by Raspy

All of a sudden, the trailer is almost independent of grid power, while having lots of modern conveniences. Uses way less water. And has a modern reliable and relatively large fridge and freezer, just like home. All in a very compact trailer. It's liberating, more comfortable and allows longer stays out in interesting places.

Yes, I’ve watched your and others evolution over the past couple of years. Given the stratospheric increase in the popularity of RVing during much the same time period, I’ve realized how much we are figuratively tied to the grid in that our trailer operates much more easily when supplemented by grid power, campsite restrooms, local grocery stores and such.

When we are able to find those sorts of sites, it’s quite freeing, much as you describe. But the competition for sites is incredible in the more populous states and near the more popular destinations.

So yes, the holding tanks and the propane cylinders are fast becoming the hallmark of a different generation of RVs. Thanks for the FOMO all you "pioneers of the lithium cells".

[Radar1]

I suspect having the ability to run the fridge on AC rather than through the batteries "might" prolong the life of the batteries, since they only have so many "charge/discharge" cycles available. (Running it down to 50% overnight and recharging would be considered 1/2 charging cycle)
If the price was close to the same I might add the 120 volt option, but I really don't know if using the 120 volts would really make much difference to extending battery life.

[CalCop]

If your're running the fridge on 120v the converter does all the work. Changing a portion of that 120 into 12v. The battery is placed in suspension while all of this is happening. Therefore the battery never actually discharges. No actual charge cycles occur.

[parmm]

Originally Posted by sean2a

Yup I’m certain Nova Kool sells a 4.3 cu fridge that will fit in the 3.0 cu footprint that is setup for an absorption. They only just started offering compressor fridges in the other models in the past couple of years, though they are going with Norcold for those models and they don’t offer quite as good of a fit fridge for the space. I’m pretty sure they’ll start offering it in the 17 in the next couple years.

Biggest benefit in doing it at this stage is the ability to keep from cutting the two outside vents. I’ll have to make my own vent from the cabinet on the inside but that’s not a problem.

https://www.novakool.com/product-specs-1

[Raspy]

The important difference is wether you are camped where you are plugged in, or camped out in the wild somewhere. It's ridiculous to run the fridge on AC if not plugged in, which builds in an immediate minimum of 10% extra loss that has to be made up by the batteries, and wasted heat from the inverter that, at least in my case, vents into the interior.

We all know that lead acid batteries can only be discharged to about 50%, and even then, they don't last very long. That 50% level is very limiting and must be adhered to. They gradually get weaker as they sulfate and pretty soon, they are almost useless, while still being demanding in how you use them. If you are running on batteries, especially lead acid it means you have a very short time before you have to re-charge somehow.

As an example of the difference between lead acid and lithium, is my lithium batteries have a twelve year warrantee and can be expected to re-charge thousands of times. I'm typically back to full charge at around noon each day, while the fridge is never turned off and no propane gets used. My depth of discharge is so minimal that the lifespan should extend further. It's not the slightest concern to me that I might be using up my limited number of re-charges. I'm not.

If you only camp where you can plug in, the batteries can be very minimal. Lead acid is fine. But if you travel and stop where you can't plug in, or seek spots where you are off-grid, more battery becomes more important. At the risk of beating a dead horse, it's very liberating to take battery management off the table and treat the trailer as a small independent cabin. I not only don't need to plug in, I turn it down when it is offered. On the last trip, with nine other trailers, I spent a lot of time helping others find plugs that worked, checking polarity, making sure they had enough cord to reach, and loaning out my dogbone adapter. There was a lot of talk about under and over voltage causing problems. Some insisted they could not get by without power and a couple of them wanted to make sure they could run a hair dryer. We ran the microwave all we wanted, left the compressor fridge on, charged the phones, radios and computers, ran lights, ran party lights outside, used the electric coffee maker all we wanted, ran the fans, etc. And we never considered plugging in. That is the difference between minimal lead acid and lithium with solar.

Run the compressor fridge on 12 volts. Have adequate batteries to keep things going without grid power. Charge with enough solar to carry your expected loads comfortably. Free yourself from having to have hookups. If you do plug in, the fridge will be perfectly happy to still run on 12 volts as the charger keeps up with the load.

A few years ago, at North Rim, there was a cacophony of generators running in the forest. I opted to charge my lead acid bats in my Oliver from the truck, with jumper cables. I could not go another day as they were at about 50%. All hooked up and idling the truck, everything seemed fine. Then a ranger stopped and informed me that I could not run my truck to charge batteries. That meant we were essentially being kicked out. No battery power and no way to charge them. I think she had to talk a bit louder because of all the generators running, which I pleasantly pointed out, to no avail. It really made me revisit the whole charging and battery scene. I either turned all power off, and let the batteries sit at minimum charge, or leave. I have nothing against minimalist camping, but it is not what I had planned with my Oliver and no fridge would have been a problem.

I have two favorite camping places in Eastern Nevada that are really representative of all of this. One is a beautiful state park, on a lake, with no hookups. The rangers are very friendly, the place is beautiful, and it is often nearly empty. Another spot close by is where we stop for the night in a parking lot with zero hassle. We can stay as long as we want, but it is used to rest on the way to Utah. No hookups. Between the two is a KOA. It is always nearly full and looks like a parking lot with trailers about 8 feet apart in a huge lot. But it has hookups. And it is terribly expensive. If those folks just drove five miles farther, they could be at the lake, in a secluded and beautiful spot. But no. They apparently need hookups and are willing to pay the price. There are other examples of this where we drive right by organized RV camping, and end up in beautiful spots where we can stay as long as we want for next to nothing. I'm not sure if I actually enjoy the morning coffee more, or the act of making it in an electric coffee maker off-grid. At first, it was an experiment. I wanted to see if could get away with making coffee the same way I do at home. But wait, while out camping, I am at home.

[Raspy]

Originally Posted by CalCop

If your're running the fridge on 120v the converter does all the work. Changing a portion of that 120 into 12v. The battery is placed in suspension while all of this is happening. Therefore the battery never actually discharges. No actual charge cycles occur.

If you are plugged in to shore power, the lead acid battery is in float on the charger, and the charger caries the loads up to its capacity. The battery does not discharge while it is on a charger. And a compressor fridge has a low draw that most any charger can keep up with. If off-grid and using 120 volts, there is at least a 10% extra load on the battery, added to the load you are running. This is the inefficiency of the inverter. Lithium batteries have so many charge/discharge cycles available for deep discharges, that it becomes meaningless to worry about small loads that they hardly notice.

If the camper is to be used off-grid, 12 volts is the best way to run the fridge, and solar can be used to make up for all loads. If plugged in, the charger carries the load anyway, so there is no downside to running the fridge on 12 volts.

[Mike_L]

My unit came with a fridge that runs on 120v AC, 12v DC and propane. I understand the fridge actually runs on DC even when plugged into shore power, through the inboard battery charger.
I use the AC power once a year, when I take my unit out of storage just to ensure it still works. I'm exclusively a boondocker so there is never any AC unless I take my generator which I used once in 10 years.
I use a 125 ah deep cycle FLA battery and 200 watts of solar power. Overnight, the battery drops about 10 - 15% of its charge powering the fridge, gas sensors etc. The battery returns to full charge about an hour after the sun comes up and I stay parked for a month or more, no difficulty.