12v Refrigeration Input Sought

[John Stone]

Hi everyone. I continue to consider adding refrigeration to the Far Reach. We have a very efficient 3.8 CF icebox we built during the rebuild. 80 lbs of block ice can last us 12-14 days. 70 lbs of cube ice lasts about 7 days. Refrigeration systems seem to be more reliable than in the past. And good ice is getting hard to find in some places. And when you find it you have to be able to get it to the boat in a timely manner. We have two big zip top LL Bean bags we use which works pretty well. Still, refrigeration would give us a little more freedom of action as long as we can manage it with our simple electrical system.

I have thought about carrying a small 12v portable fridge like the Engle MT 35 we use with our Jeep. A great piece of equipment. We have be impressed with its performance and low amp use. But I don't want to install anything that takes up more space. I don't want a portable fridge strapped to the q berth or under the saloon table. I could take out our ice box and build a compartment for a portable 12v like the Engle which could be a good way to go. It would be under the chart table and all the cabinetry would look the same as it does now. But then I am committed to it and it essentially destroys a very efficient ice box so I don't think I want to do that.

If I install refrigeration I am thinking I should make use our efficient box with an isotherm 2050 SP like Jim Walsh. It uses an evaporator plate. Supposed to be very efficient esp with an option ITC controller.

But isotherm also makes a 3251 SP that uses a cold plate. I read an interesting review on the 3251 using only 12 amps a day (lots of variables there of course). https://www.ventspleen.com/isotherm-sp- ... ge-review/

Here is the 3251 sp holding plate unit. https://www.indelwebastomarine.com/us/p ... e-control/

Here is the 2050 sp evaporator plate unit. https://www.indelwebastomarine.com/us/p ... e-control/

The isotherm tech rep I chatted with on the phone said both units are excellent. Both are sized appropriately for our 3.5 cf icebox. But, he would chose the 3251 SP if the box is very efficient and if the cold plate will fit (it will). He said it's more efficient and uses less energy than the 2050 SP. I have read different perspectives on these two approaches. Seems many people argue the evaporator is the way to go on a 12 v system though the tech guy argued different.

I don't use the engine to charge batteries. So far we easily handle everything with our T105 Trojans, it's 225 ah bank, and our 90 watts of solar. I don't want new batteries. I don't want complicated systems or to change my alternator or anything like that.

I am interested in hearing from anyone with experience with a 12v system--especially a cold plate system. Of course I am always happy to listen to what forum members have to say but my focus is improving my understanding about the pros and cons of these two systems and especially any personal experience folks might have with them.

Thanks.

[jbenagh]

John,
I put in an Isotherm last year, similar to Jim Walsh and Steve Laume http://capedory.org/board/viewtopic.php?f=9&t=37713
I put in a bunch of insulation and relined the box with glass and epoxy.
I didn't get to cruise much last summer but I got about five days of close to cruising use. In Mass Bay, with water temps around 65F I used about 20Ah per day to run the unit. I don't have a good way to accurately measure that but I did monitor the duty cycle on the compressor and the amps while it was running. This was in line with the manufacturers specs.
Sorry, I'm just on phone so I don't have the icebox volume or the IsoTherm details. Lmk if you can't find them from that post and I'll look them up tomorrow.
Happy sailing!
Jeff

[wikakaru]

Hi John,

One of my boats had a SeaFrost holding plate system with an engine driven compressor, and another had a SeaFrost 12-volt system with an evaporator plate. It's not exactly the comparison you were asking for, but maybe something I can tell you about those systems will help you with your decision.

The holding plate system was good in some ways: we didn't have enough solar capacity to feed a 12-volt refrigeration system on that boat, so we were had to run the engine anyway. The compressor cooled down the plate quickly, and for the most part it kept things cold for 24 hours until we had to run the engine again.

Personally I preferred the 12 volt evaporator plate system, as the temperatures stayed within a small range all the time rather than fluctuating more broadly as they did with the holding plate system. That system could run for several days on our batteries, so if we weren't going anywhere we didn't need to run the engine just for refrigeration. The other big benefit was that we could run the 12v fridge when the boat was out of the water, so if we were doing work at the boatyard we still had refrigeration. If that is important to you, you should check and see if either of the systems require water cooling. Our 12v evaporator system had a water cooling "boost", but was also air-cooled and didn't require water cooling to operate.

I assume that the 12v holding plate system you are looking at has a bigger compressor and pulls more current in a shorter time than the 12v evaporator system, so it will require bigger wiring. If your wiring runs are very long, that's something to consider.

Beyond those factors, to me what it would boil down to is whether your solar panels and batteries can keep up with the refrigeration demands in marginal conditions--like after a series of several cloudy days. If you are going to wind up running the engine frequently to charge things up anyway, it may be better to make the cold as quickly as possible and store it in the holding plate. If you can do without the engine for charging, a fridge that runs at a lower draw all or most of the time will be fine.

I hope that helps!

Smooth sailing,

Jim

[John Stone]

Thanks to both of you for responding.

The holding plate is 12v driven. It actually is supposed to use less power @ .4 amps/hr. The evaporator plate uses .7 a/h. That's according to the literature and is also what the tech guy said. It surprised me. It's consistent though with the article I linked to above. The isotherm tech rep stated the key for holding plate is a good box. Which we have. If not a good box or the holding plate won't fit them go with evaporator plate.

Also, unlike engine driven the 12v keeps the cold plate cold when needed to maintain the temp we set.

But, again it's contrary to what I have read on the internet. But some folks may not be familiar with the 12v driven holding plate. I don't know. No experience with them.

Regarding the water cooled through hull. Isotherm states it works fine on the hard as well. Says it works like a chimney drawing heat up across the coil through the sink drain. But reality is I would not see us using it in the hard. But...I simply don't know.

Does any of that info change your thinking?

[Jim Walsh]

Thanks to both of you for responding.
Regarding the water cooled through hull. Isotherm states it works fine on the hard as well. Says it works like a chimney drawing heat up across the coil through the sink drain. But reality is I would not see us using it in the hard. But...I simply don't know.

That’s true. I tested it on the hard just for kicks. Their operating instructions stress that the sink drain not be plugged so it can operate efficiently.

[wikakaru]

Thanks to both of you for responding.

The holding plate is 12v driven. It actually is supposed to use less power @ .4 amps/hr. The evaporator plate uses .7 a/h. That's according to the literature and is also what the tech guy said. It surprised me. It's consistent though with the article I linked to above. The isotherm tech rep stated the key for holding plate is a good box. Which we have. If not a good box or the holding plate won't fit them go with evaporator plate.

Also, unlike engine driven the 12v keeps the cold plate cold when needed to maintain the temp we set.

But, again it's contrary to what I have read on the internet. But some folks may not be familiar with the 12v driven holding plate. I don't know. No experience with them.

Regarding the water cooled through hull. Isotherm states it works fine on the hard as well. Says it works like a chimney drawing heat up across the coil through the sink drain. But reality is I would not see us using it in the hard. But...I simply don't know.

Does any of that info change your thinking?

That's interesting. The rating of .4 amps/hr vs .7 amps/hr is a cumulative current over time, not the instantaneous power draw when the compressor is running. I checked the web sites you referenced, and both the systems use the same BD35F compressor, with a maximum power consumption of 78.5 watts according to manufacturer specs. So the wiring sizes should be the same or similar, depending on other components like fans and electronics. I don't understand why the holding plate system would use less power to operate than the evaporator system if they have the same compressor and are both thermostatically controlled. Maybe it has to do with the different temperatures in the plates, since the compressor will draw different amounts of power depending on the temperature of the system and speed of the compressor. But I'm not an expert, just a guy who has read Nigel Calder's books a few times and occasionally topped up the refrigerant in a system here and there. So I defer to the experts.

Smooth sailing,

Jim

[John Stone]

Thanks to both of you for responding.

The holding plate is 12v driven. It actually is supposed to use less power @ .4 amps/hr. The evaporator plate uses .7 a/h. That's according to the literature and is also what the tech guy said. It surprised me. It's consistent though with the article I linked to above. The isotherm tech rep stated the key for holding plate is a good box. Which we have. If not a good box or the holding plate won't fit them go with evaporator plate.

Also, unlike engine driven the 12v keeps the cold plate cold when needed to maintain the temp we set.

But, again it's contrary to what I have read on the internet. But some folks may not be familiar with the 12v driven holding plate. I don't know. No experience with them.

Regarding the water cooled through hull. Isotherm states it works fine on the hard as well. Says it works like a chimney drawing heat up across the coil through the sink drain. But reality is I would not see us using it in the hard. But...I simply don't know.

Does any of that info change your thinking?

That's interesting. The rating of .4 amps/hr vs .7 amps/hr is a cumulative current over time, not the instantaneous power draw when the compressor is running. I checked the web sites you referenced, and both the systems use the same BD35F compressor, with a maximum power consumption of 78.5 watts according to manufacturer specs. So the wiring sizes should be the same or similar, depending on other components like fans and electronics. I don't understand why the holding plate system would use less power to operate than the evaporator system if they have the same compressor and are both thermostatically controlled. Maybe it has to do with the different temperatures in the plates, since the compressor will draw different amounts of power depending on the temperature of the system and speed of the compressor. But I'm not an expert, just a guy who has read Nigel Calder's books a few times and occasionally topped up the refrigerant in a system here and there. So I defer to the experts.

Smooth sailing,

Jim

Jim
Thanks. Well I just don't know. I understand how the two systems are different but don't really understand the pros and cons of the two systems. I other words I don't know why to chose one over the other. But I do want a system that uses the absolute least power because if I suddenly find myself hurtling down the more power path I will have failed and I will be very unhappy.

We just got back from our hike to the petroglyphs. I checked our battery monitor. 13.4v. That's what I am talking about.

I can see the argument for a wind generator to charge the bank at night. And they seems to be making them very quiet. I just don't want one. Maybe I should let the idea of a fridge slide. Plenty of time to think about it on the sail home.

Anyone else with experience or thoughts to share on this topic?

[tjr818]

Back in the old days there used to make gas refrigerators,both for home use and for RV camping. How would one of those compare?

[John Stone]

Back in the old days there used to make gas refrigerators,both for home use and for RV camping. How would one of those compare?

Yep. They used to make em that ran off kerosene too. I think the Hiscocks might have used something like that for a while. But they didn't have anything like 12v solar back then which is very capable today. So I don't really know. This is an area in which the only experience I have is my 35 liter Engle MT 35 12v fridge. Other than that I have read about it, I have talked with people that have 12v systems in the caribbean. Jim Walsh whose input I think is very valuable has some experience he has shared and that has shaped my thinking a bit.

My problem with Nigel Calder and folks like him is he has tremendous faith in technology. He likes it. He explains it well. He understands it. I am pretty much on the other end of the spectrum. I see it as a burden. A pain in the ass. Difficult and expensive to repair. Another piece of technology that will at some point fail (no doubt about that) and which I have to spend precious time on trying to understand. I want simple reliable self-repairable. When I start hearing people drone on about batteries and equalization and inverters and amp hours and charging regimens and blah blah blah my eyes glaze over and I find it a huge bore.

So my interest in 12v refrigeration has me operating a little against my nature because I have begun to wonder if this could be valuable to me and make my sailing experience better for me they way I sail without crossing over onto a path that is out of synch with my personal philosophy and what I try to get out of sailing.

Does that make sense?

[tjr818]

My Dad used to say; I spent a lot of my younger of my life acquiring and owning fine tools and machines only to find out that I didn't own them . . . they owned me. All those complicated tools required more and more time to maintain. He went back to simple hand tools, a hand plane, a nice Disston saw, an eggbeater hand drill, and his favorite tool, a draw knife (which I now own and cherish.) Luddites have more fun.

[John Stone]

My Dad used to say; I spent a lot of my younger of my life acquiring and owning fine tools and machines only to find out that I didn't own them . . . they owned me. All those complicated tools required more and more time to maintain. He went back to simple hand tools, a hand plane, a nice Disston saw, an eggbeater hand drill, and his favorite tool, a draw knife (which I now own and cherish.) Luddites have more fun.

How do I "like" this comment?

[wikakaru]

Back in the old days there used to make gas refrigerators,both for home use and for RV camping. How would one of those compare?

Propane refrigerators are still common in RVs. I think they aren't used on boats because they have an open flame that is sensitive to angle of operation, and the boat's motion either causes the system not to work or to become a fire danger. I'm not sure which is the case (maybe it's both), but there is a reason they are not used on boats.

Smooth sailing,

Jim

[wikakaru]

Thanks. Well I just don't know. I understand how the two systems are different but don't really understand the pros and cons of the two systems. I other words I don't know why to chose one over the other. But I do want a system that uses the absolute least power because if I suddenly find myself hurtling down the more power path I will have failed and I will be very unhappy.

We just got back from our hike to the petroglyphs. I checked our battery monitor. 13.4v. That's what I am talking about.

I can see the argument for a wind generator to charge the bank at night. And they seems to be making them very quiet. I just don't want one. Maybe I should let the idea of a fridge slide. Plenty of time to think about it on the sail home.

Anyone else with experience or thoughts to share on this topic?

We had both wind and solar on our Pacific Seacraft 34. We found that solar produced far more energy than wind. The wind systems need a good 15 knots of breeze before they really start producing. We occasionally had times when we had long periods of foul weather where we were glad to have the wind generator, but most of our power came from solar most of the time. If you add wind power because your solar can't meet your demands, then you start making the choice of whether to anchor in less protected anchorages to maximize your wind power, or more sheltered ones that provide better safety. That's not a good choice to even begin to consider. Having had both, my advice is that unless you plan to cruise in places where you expect long periods of obscured sun and high winds together (like arctic regions), if you need more power without resorting to fossil fuels, find a way to mount more solar panels.

As to noise, we had one of the "quiet" wind systems (an Air X), and it was still fairly noisy. You have to put rubber anti-vibration mounting bases at ALL points of contact with the hull. (Typically you need at least 3 points of contact.) Even with rubber mounting bases there is still a fair bit of vibration that makes it into the hull. The boat becomes a sounding box. (Think about how a guitar works.) Plus there is the noise of the blades themselves.

Maybe what you should do, John, is try your Engle cooler in a non-permanent installation on the boat as a test run first. See how it performs, and how quickly it depletes the batteries with the charging system you have. Take a test cruise in North Carolina so you have a feel for it without committing to it for a whole Caribbean cruise. A well-installed, well-insulated permanent system should out-perform the cooler, so if you can make the cooler work, you should be able to make a permanent installation work. If it doesn't work, or you decide you aren't willing to commit, you haven't chopped up the interior of the boat or drilled any holes in your perfectly good ice box.

Smooth sailing,

Jim

[wikakaru]

My Dad used to say; I spent a lot of my younger of my life acquiring and owning fine tools and machines only to find out that I didn't own them . . . they owned me. All those complicated tools required more and more time to maintain. He went back to simple hand tools, a hand plane, a nice Disston saw, an eggbeater hand drill, and his favorite tool, a draw knife (which I now own and cherish.) Luddites have more fun.

How do I "like" this comment?

+1 on that. It really is true that our possessions own us, not the other way around. That is why I have switched to sailing small boats with few or no systems. More fun, less work. I can even afford to pay someone really good like Tim Lackey to do a full refit of my little CD22 for about the same cost as a single project (like adding solar/wind, for example, since that is part of this discussion) on a big boat.

Smooth sailing,

Jim

[John Stone]

Thanks. Well I just don't know. I understand how the two systems are different but don't really understand the pros and cons of the two systems. I other words I don't know why to chose one over the other. But I do want a system that uses the absolute least power because if I suddenly find myself hurtling down the more power path I will have failed and I will be very unhappy.

We just got back from our hike to the petroglyphs. I checked our battery monitor. 13.4v. That's what I am talking about.

I can see the argument for a wind generator to charge the bank at night. And they seems to be making them very quiet. I just don't want one. Maybe I should let the idea of a fridge slide. Plenty of time to think about it on the sail home.

Anyone else with experience or thoughts to share on this topic?

We had both wind and solar on our Pacific Seacraft 34. We found that solar produced far more energy than wind. The wind systems need a good 15 knots of breeze before they really start producing. We occasionally had times when we had long periods of foul weather where we were glad to have the wind generator, but most of our power came from solar most of the time. If you add wind power because your solar can't meet your demands, then you start making the choice of whether to anchor in less protected anchorages to maximize your wind power, or more sheltered ones that provide better safety. That's not a good choice to even begin to consider. Having had both, my advice is that unless you plan to cruise in places where you expect long periods of obscured sun and high winds together (like arctic regions), if you need more power without resorting to fossil fuels, find a way to mount more solar panels.

As to noise, we had one of the "quiet" wind systems (an Air X), and it was still fairly noisy. You have to put rubber anti-vibration mounting bases at ALL points of contact with the hull. (Typically you need at least 3 points of contact.) Even with rubber mounting bases there is still a fair bit of vibration that makes it into the hull. The boat becomes a sounding box. (Think about how a guitar works.) Plus there is the noise of the blades themselves.

Maybe what you should do, John, is try your Engle cooler in a non-permanent installation on the boat as a test run first. See how it performs, and how quickly it depletes the batteries with the charging system you have. Take a test cruise in North Carolina so you have a feel for it without committing to it for a whole Caribbean cruise. A well-installed, well-insulated permanent system should out-perform the cooler, so if you can make the cooler work, you should be able to make a permanent installation work. If it doesn't work, or you decide you aren't willing to commit, you haven't chopped up the interior of the boat or drilled any holes in your perfectly good ice box.

Smooth sailing,

Jim

Thanks Jim. Lots of good input. I have run down those lines of thinking for months (if not years) and from every angle I can think of. All your comments are accurate. But it's good to hear it again. These are issues with significant impact on me and my boat. All those complications and hassles are why I don't have that stuff. We plan to do just that with the Engle. Even if we only put the Engle on the boat for 24 hours when J get home this summer just to see what happens regarding energy use. It's an important data point I'd like to have.

All your comments on wind generators match everything I have read and learned talking to owners, except they are so much more quiet today than the Air-X. The D-400 (very expensive and heavy) as well as the Silent Wind are amazingly quiet. I have seen/heard them working in West Indies anchorages and you can barely hear them 15' away turning fast in 20+ kts. I have talked to many owners. But they are kind of unsightly, cumbersome, expensive, complicated and require a fair amount of wind to work well (I have sketched different ways to mount a wind generator and have not come up with anything I like). But, while my 90 watts of solar might support a small fridge here in the sunny Caribbean it probably will it be insufficient in cloudy European waters. The addition of a fridge is a huge step in power usage. I'm still thinking and gathering info.

I have also thought a lot about going to dinghy cruising for all the reasons you listed. My preferences are usually smaller and less complicated for maximum flexibility. It's a big step but nothing is off the table but it's not so much if, but when.

I will only keep the Far Reach as long as I am actively sailing (or making plans to sail) over the horizon. She is not built for local coastal cruising which was never part of my plan. I head home in about six weeks or less. I am mulling all these things over....