Why consider 12v fridge for boondocking?

[Vintage465]

So I want to offer up this question out about 12v compressor refrigerators. I'm going to post this on other forums too, so your "forum tramps"(like me)may see this spread around some other pages. Not interested in thoughts regarding space savings, preferance due to fear of propane gas or performance of a 12v vs. propane fridge. Taking all those criteria out, we are left with why or why not. Having said all that this is the base of the question: I keep seeing people use the words "boon docking" and "12v compressor fridges" in the same sentance as though there is an advantage to having a 12v fridge while boon docking. I believe that an absorption fridge is the best boon docking choice because propane nearly lasts forever(at least a month) compared to 12v fridges that are dependent on recharging the battery bank daily. When responding...........not interested in anything other than energy sustainability while boon docking. I also am not interested in peoples opinions on performance between the two as I've never had any issue with any absorption fridge keeping things cool event in 110 degree temps. Just energy sustainability while boon docking.

Thanks!

[OkieGene]

Well it's a good thing the price of LiFePO batteries have dropped tremendously.

The gold standard has probably been Battle Born batteries at roughly $1,000 each for a 12 volt 100amp battery. They're good, no doubt.

However, now you can buy LiFePO 12 volt 100 amp batteries for $299 each. May not have all the bells and whistles of the $1,000 batteries, but there it is.

[Huntindog]

Fisherguy wrote:

I have what most would consider to be a healthy solar/battery system. But if I were to add a 12V fridge to the draw, I would come up short a lot.... And adding to what already have is not so easy. It would be quite expensive, and make my roof so full that I would not have room to do maintainence up there.
Saying the additonal cost would be minimal. just shows that you do not have a clue as to what is involved. Another controller, another wire run up to the roof more fuses, more panels, more batteries more cables etc. Using what I consider to be quality stuff (to match what I already have), would be at least 3k. Probably closer to 4K

With 1800 watts of solar and 800AH of Lithiums I don't think you'd need to do any upgrades for a 12 volt fridge.Maybe you wouldn't. But I would.

[Huntindog]

DP

[Fisherguy]

I have what most would consider to be a healthy solar/battery system. But if I were to add a 12V fridge to the draw, I would come up short a lot.... And adding to what already have is not so easy. It would be quite expensive, and make my roof so full that I would not have room to do maintainence up there.
Saying the additonal cost would be minimal. just shows that you do not have a clue as to what is involved. Another controller, another wire run up to the roof more fuses, more panels, more batteries more cables etc. Using what I consider to be quality stuff (to match what I already have), would be at least 3k. Probably closer to 4K

With 1800 watts of solar and 800AH of Lithiums I don't think you'd need to do any upgrades for a 12 volt fridge.

[Huntindog]

valhalla360 wrote:

Grit dog wrote:
9 pages later, ^ here’s a good dose of common sense and truth.
Being more “efficient” in one way doesn’t necessarily mean less costly.
Sure both have different advantages and disadvantages but apples to apples, especially if considering replacing a perfectly good absorption fridge, it’s not even close.

Truth depends heavily on the assumptions.

Tearing out a relatively new perfectly functional appliance rarely makes sense, no matter how bad the existing technology is. Are you going to rip out the perfectly functional 5 speed transmission in your truck and retrofit one of the new 10 speed units because it's better...of course not. It's a silly comparison.

If you are boondocking a lot with a single 12v starting battery and no solar, yeah, absorption is by far the better option but that's not a typical use pattern.

Vast majority of RVs rarely operate away from shore power. For these rigs, 12v compressor fridges are better both in terms of efficiency but also in terms of better operation (faster cooldown, able to hold colder temps, larger interior volume, etc....). I'm betting this represents 80-90% of new RV buyers, so this is where the manufacturers are focused.

For those who do a lot of boondocking, most will be installing a larger battery bank and solar anyway. Up sizing it to accommodate the relatively modest requirements of the 12v fridge is easy and doesn't incur a major cost. The cost difference between installing a couple of 200w panels and a couple of 300w panels, is pretty minimal. A few seasons of reduced propane use will cover the cost.

I have what most would consider to be a healthy solar/battery system. But if I were to add a 12V fridge to the draw, I would come up short a lot.... And adding to what already have is not so easy. It would be quite expensive, and make my roof so full that I would not have room to do maintainence up there.
Saying the additonal cost would be minimal. just shows that you do not have a clue as to what is involved. Another controller, another wire run up to the roof more fuses, more panels, more batteries more cables etc. Using what I consider to be quality stuff (to match what I already have), would be at least 3k. Probably closer to 4K

[StirCrazy]

valhalla360 wrote:

Grit dog wrote:
9 pages later, ^ here’s a good dose of common sense and truth.
Being more “efficient” in one way doesn’t necessarily mean less costly.
Sure both have different advantages and disadvantages but apples to apples, especially if considering replacing a perfectly good absorption fridge, it’s not even close.

If you are boondocking a lot with a single 12v starting battery and no solar, yeah, absorption is by far the better option but that's not a typical use pattern.

For those who do a lot of boondocking, most will be installing a larger battery bank and solar anyway. Up sizing it to accommodate the relatively modest requirements of the 12v fridge is easy and doesn't incur a major cost. The cost difference between installing a couple of 200w panels and a couple of 300w panels, is pretty minimal. A few seasons of reduced propane use will cover the cost. Manufacturers are still on the learning curve but they are starting to outfit RVs with solar options. Not just for the fridge but for other convienences.

your baking some pretty bold asumptions, I have four 6V batteries and 480 watts of solar on the 5th which cost me over 6K at the time (didnt realize how easy it was to install and save money, plus rices have realy dropped over the last 6 years but not to crazy) right now I could not support the extra 60+ AH/day a compressor fridge would add in my climate. ya I could go for a weekend maybe, but would drfinatly run out of power on the 3rd day. plus the extra deep cycling on the batteries would wear them out faster. I would have to replace my pannels with larger ones say 600 bucks there, a new solar controler 3-400, and a switch over to LFP batteries to get more usable panels. lets say I buy them and don't make them myself so it applies more to the average person and we will go middle price of 700 each X 4 is = 2800 bucks so thats an upgrade cost to me of 3800 bucks with me doing the instalations now days to do the system I have would be about 2000 doing the instalation yourself. so double the cost and power to support a compressor fridge. granted this is for the way I like it set up, which is I can stay out forever with out having to worry about power, but even so a few dark non solare days and you will be watching the remaining battery levels...

with a adsorbsion fridge I don't have to worry about my food spoiling if there is no sun, I just use the perculator instead of the keriug.

in adition to the bigger solar system, you might need a genny back up just for thoes dark days, personaly I hate gennys and am thankfull there are more restrictions being put on there use but a buit in one of thoes is what 6K? a deicent honda a couple k?

so assuming just cuz some one boon docks already they will be set up properly for a compressor fridge is a very bold asumption.

[goducks10]

I installed my 12V fridge because my Norcold quit working 1.5 years into service.
I had already prepped my TT for boondocking. Four 6V GC batteries, 400W solar (Now 600w) and a 2000W inverter.
It made sense to go 12V under those circumstances. Had I not already made the upgrades I would've went with a JC conversion. Price for either was a wash. But the 12V offered 2 more cu.ft of space and was much simpler in regards to operation and as mentioned I was already setup for it.
Even if I had all that stuff added for boondocking there would be no reason to remove the NC and go 12V. A 12V just puts added strain on the batteries of which could be used for other purposes.

I would add that in the 1st year of adding all the solar and batteries we never needed the gen once. Now after adding the 12V fridge I need to rely on the gen more. YMMV

[valhalla360]

Grit dog wrote:
9 pages later, ^ here’s a good dose of common sense and truth.
Being more “efficient” in one way doesn’t necessarily mean less costly.
Sure both have different advantages and disadvantages but apples to apples, especially if considering replacing a perfectly good absorption fridge, it’s not even close.

Truth depends heavily on the assumptions.

Tearing out a relatively new perfectly functional appliance rarely makes sense, no matter how bad the existing technology is. Are you going to rip out the perfectly functional 5 speed transmission in your truck and retrofit one of the new 10 speed units because it's better...of course not. It's a silly comparison.

If you are boondocking a lot with a single 12v starting battery and no solar, yeah, absorption is by far the better option but that's not a typical use pattern.

Vast majority of RVs rarely operate away from shore power. For these rigs, 12v compressor fridges are better both in terms of efficiency but also in terms of better operation (faster cooldown, able to hold colder temps, larger interior volume, etc....). I'm betting this represents 80-90% of new RV buyers, so this is where the manufacturers are focused.

For those who do a lot of boondocking, most will be installing a larger battery bank and solar anyway. Up sizing it to accommodate the relatively modest requirements of the 12v fridge is easy and doesn't incur a major cost. The cost difference between installing a couple of 200w panels and a couple of 300w panels, is pretty minimal. A few seasons of reduced propane use will cover the cost. Manufacturers are still on the learning curve but they are starting to outfit RVs with solar options. Not just for the fridge but for other convienences.

To find a place where your "truth" holds, you need to start looking at specialty cases that split the difference. Maybe someone who camps 60 nights per year with 15 of them boondocking and other than the fridge they are used to being very rustic (ie: using almost no 12v power when not on shore power). It's enough use where relying on shore power is problematic but they wouldn't otherwise need a solar system.

[Vintage465]

ktmrfs wrote:

StirCrazy wrote:
when it comes to power usage, a 12V is not near as energy efficient (battery power wise) as an adsorbition fridge. you will need much more battery capacity and solar or a generator if you switch to 12V compressor.

In terms of BTU or KWH needed to cool, compressor driven fridges are much more efficient than a absorption fridge. Generally you can get about 3x the input BTU used in cooling BTU from a compressor driven fridge. No it doesn't violate any laws of physics, it's the energy needed to move heat from one place to another.

By contrast an absoprtion fridge is much less efficient COP is on the order of 0.7 or less vs 3 or more for compressor fridges.

But in terms of how the energy is stored to use the fridge, propane in BTU/gallon or BTU/weight or BTU/volume FAR FAR FAR exceeds any battery for the same volume or weight.

And ultimately this is my point, and why I still use an Absorption unit: "But in terms of how the energy is stored to use the fridge, propane in BTU/gallon or BTU/weight or BTU/volume FAR FAR FAR exceeds any battery for the same volume or weight."

[Reisender]

Hmm. Is a bit of a guess but I’ll say 8 or 10 hours maybe. We used it 6 or 7 times for trailer battery charging on our cross country Canada trip, maybe 45 minutes to an hour every time and the tank still had some in it when we got home. We have to pack our front box of the trailer light because I’m trying to keep my hitch weight under 350 pounds. Hindsight says I had enough room for a 10 pounder but at the time the 5 pounder seemed like a better choice. One thing about small combos, you gotta watch everything you pack. :).

[theoldwizard1]

Reisender wrote:
Yah I hear you. Hence our back up plan with our little propane generator. :).

Curious. How many hours do you get on that generator on that small propane bottle ?

[Fisherguy]

Vintage465 wrote:

Fisherguy wrote:

Vintage465 wrote:


... The day will come when everything will be 12v compressor and we will all need to adjust and by that time the solar and batteries will surely be up to the task.

And on that note I'm looking for advice. I have a chance to buy a trailer with 600 watts of solar panels, 3 - 100 Ah Lithiums and a 12 volt Norcold fridge.

I'll be installing a small inverter to power the TV and sat dish but no coffee makers or toasters etc for us.
If we only boondock do you think this setup will work for us? Maybe if I add another 200 watt panel and another 100Ah of Lithium?

We only very rarely need to run the genny to charge batteries with our current rig in my signature.
Thx

I think you have a good start there, but I'm certainly not any kind of expert on 12v longevity from a power stand point. But based on what you have and are willing to add to it you should be able hold out. You may encounter some issues if you winter camp using that kind of energy.

Thanks.
It will be interesting. I've been doing a lotta research, apparently Lithium batteries charge a lot quicker than lead/acid as well which is good, the less genny time the better.

[Grit_dog]

9 pages later, ^ here’s a good dose of common sense and truth.
Being more “efficient” in one way doesn’t necessarily mean less costly.
Sure both have different advantages and disadvantages but apples to apples, especially if considering replacing a perfectly good absorption fridge, it’s not even close.

[goducks10]

There's no way a 12V fridge costs less than an absorption fridge to run or to install. Between the solar panels, larger/or more batteries and controller you can get an absorption fridge for much less and only need propane to run it on for weeks.

You have to have the best weather conditions and be in open view of the sky for the solar to work best. If not you need to buy and generator to compensate. Then buy gas.
Regardless of which one use less power, it's which power has the best upside.
Propane doesn't care if it's 90* and sunny or raining. It's going to run the fridge 24/7. Solar only runs the fridge in daylight. Batteries at night.
Batteries need recharged, rinse repeat until it rains or it's cloudy or you're in the trees. Then it's time to drag out the gen.

[StirCrazy]

ktmrfs wrote:

StirCrazy wrote:
when it comes to power usage, a 12V is not near as energy efficient (battery power wise) as an adsorbition fridge. you will need much more battery capacity and solar or a generator if you switch to 12V compressor.

In terms of BTU or KWH needed to cool, compressor driven fridges are much more efficient than a absorption fridge. Generally you can get about 3x the input BTU used in cooling BTU from a compressor driven fridge. No it doesn't violate any laws of physics, it's the energy needed to move heat from one place to another.

By contrast an absoprtion fridge is much less efficient COP is on the order of 0.7 or less vs 3 or more for compressor fridges.

But in terms of how the energy is stored to use the fridge, propane in BTU/gallon or BTU/weight or BTU/volume FAR FAR FAR exceeds any battery for the same volume or weight.

if you looked I did preamble this in terms of power usage as in how much power is required of the batteries.. I understand the other side already but thats not the issue here. the issue is how much more it would cost in batteries solar panels or generator to boon dock with a 12V compressor fridge.