12v Refrigeration Input Sought

[Jack.Ducas]

John, I haven't seen any mention on this thread of the cold plate,12v refrigeration system that I've been using for the past 10-12 years or so called Cool Blue Refrigeration. I really can't comment on the amp/watt usage as I'm clueless with that kind of stuff but I will say it's pretty damn efficient and the compressor doesn't take up much space. It will freeze water that accumulates in the bottom of the ice box. I have to believe you can find out more about the electrical demands this thing will use online. FWIW I've been extremely happy with it. No, I'm not affilliated with the company in any way, shape or form and I will say their technical support is very good. I just figured I'd throw out another option you might want to investigate.

[John Stone]

John, I haven't seen any mention on this thread of the cold plate,12v refrigeration system that I've been using for the past 10-12 years or so called Cool Blue Refrigeration. I really can't comment on the amp/watt usage as I'm clueless with that kind of stuff but I will say it's pretty damn efficient and the compressor doesn't take up much space. It will freeze water that accumulates in the bottom of the ice box. I have to believe you can find out more about the electrical demands this thing will use online. FWIW I've been extremely happy with it. No, I'm not affilliated with the company in any way, shape or form and I will say their technical support is very good. I just figured I'd throw out another option you might want to investigate.

Jack,
Excellent! So you have a 12v cold plate system? Do you know the model so I can check against size? What can you tell me about your installation? How big is your fridge box? Stock box or custom? How do you keep it charged--engine? Solar? Generator?

Thanks much.

I'd love to hear more about it.

[Jack.Ducas]

John, Cool Blue refrigeration is a 12v cold plate unit. FAYAWAY is a 1982 CD30 cutter that's an original boat with the original ice box. I don't know how many cubic ft of space is in it. I mounted the compressor in the storage area just above and behind the box. It just barely fits in there and allows the sliding door for the compartment to still be opened and closed. The cold plate is approximately 24"x16"x1 3/4" and is mounted against the wall of the box closest to the companion way steps. I'm using engine and solar to keep the batteries topped up when cruising and obviously when at the dock the battery charger takes care of that. Sorry about not having the model number as all paperwork for it is at the boat. It's been a great unit.

[John Stone]

John, Cool Blue refrigeration is a 12v cold plate unit. FAYAWAY is a 1982 CD30 cutter that's an original boat with the original ice box. I don't know how many cubic ft of space is in it. I mounted the compressor in the storage area just above and behind the box. It just barely fits in there and allows the sliding door for the compartment to still be opened and closed. The cold plate is approximately 24"x16"x1 3/4" and is mounted against the wall of the box closest to the companion way steps. I'm using engine and solar to keep the batteries topped up when cruising and obviously when at the dock the battery charger takes care of that. Sorry about not having the model number as all paperwork for it is at the boat. It's been a great unit.

Thanks. After your response I read up on it. Seems like a good system. There is a large 9 pg thread on the cruiser forum about it. I don't frequent that forum but that was the link that popped up when I googled Cool Blue 12v. There is however some good info on the thread and by all accounts you have a good unit with excellent customer support. As is almost always the case the forum thread eventually spiraled down into an argument about electrons, string theory, the origins of the universe blah blah blah yawn.

Here ya go--https://www.cruisersforum.com/forums/f1 ... 916-4.html

Anyway thank you for your initial response and follow on info as I continue to get a wee bit smarter about what might work for us and what probably won't.

[Jack.Ducas]

John, I just glanced at the cruiser's forum link you sent. Cool Blue is supported by Technautics and Rich Boren, a contributer to the thread(fellow criuser I believe) is the man I spoke with on technical issues. Very informative 24/7, I'll vouch for that and he'll answer the phone! something I place a high value on. None of the message machine I'll get back to you crap, very rare in todays world. Good luck in finding just what fits the bill.

[John Stone]

John, I just glanced at the cruiser's forum link you sent. Cool Blue is supported by Technautics and Rich Boren, a contributer to the thread(fellow criuser I believe) is the man I spoke with on technical issues. Very informative 24/7, I'll vouch for that and he'll answer the phone! something I place a high value on. None of the message machine I'll get back to you crap, very rare in todays world. Good luck in finding just what fits the bill.

Copy. Rich Boren definitely comes off in that thread as a reasonable person and company owner committed to producing satisfied customers.

The cold plate is probably too big for my small icebox.

[Jack.Ducas]

I'm sure Rich can tell you exact measurements of the cold plate. Measurements I gave you were all estimates. Good luck

[fmueller]

John,

I put an Isotherm 3751 in my unmodified CD 27 icebox. Just bolted the plate sideways in the OEM box, compressor on a shelf imediately abaft in the stbd locker.


https://www.defender.com/product.jsp?pa ... id=6625587

https://www.dropbox.com/s/y4tsosks6tzmo ... s.jpg?dl=0

https://www.dropbox.com/s/qtqa3airp3ncs ... s.jpg?dl=0

As far as I have been able to tell it runs about 10 minutes every hour in 2-3 minute bursts. This is while hooked up to shore power when it will run full on at about 6 amps (it senses more than 13 volts on the 12 volt system). So that works out to about 24 amp hours a day. When it senses 12.8 volts or less it reduces current draw to 3 amps (ie when you are sailing). Not sure how this matters ... it would presumably have to run longer for same amount of cooling, but I have not paid close attention - this is a "feature". Suffice to say, I could reduce power required if I'd improve the oem insulation factor (lazy). But for me, just having a little fridge when the boat is mostly on the slip all summer is great. I can leave beers, apples, cheese, eggs, sausage etc and be ready to go for a day or two or three. But I've only got 2 group 27 AGMs and 200 amps / 100 effective so keeping the system on for more than a day or two cruising becomes problematic - except if I motor sail for a good part of a day. When I do take off for overnight, I'll load two bags of ice into the space, partly just to have cubed ice!!!!, then try to remember to snap the compressor on when/if motoring. I can gunkhole around quite nicely this way for the better part of a week, esp if I snag more ice or get some shore power for a night. If I lean a gallon of water up against the plate it will freeze it, but for the most part the space acts as a fridge now, but colder in the bottom, warmer on the little shelves

The water cooled coil is smart, built into my stbd cockpit scupper, and the compressor is basically silent (masked) if you have any wind or water noise at all - which when you think of it is what makes boats charming, and sometime perplexing, all those little sounds.

cheers

Edit: I think what I am trying to say is you can lower the “tech dependency” quotient by realizing you still have your good old ice box with the addition of cooling “sometimes”. But by all means if it’s convenient, pick up some block ice and continue as before …

[John Stone]

John,

I put an Isotherm 3751 in my unmodified CD 27 icebox. Just bolted the plate sideways in the OEM box, compressor on a shelf imediately abaft in the stbd locker.


https://www.defender.com/product.jsp?pa ... id=6625587

https://www.dropbox.com/s/y4tsosks6tzmo ... s.jpg?dl=0

https://www.dropbox.com/s/qtqa3airp3ncs ... s.jpg?dl=0

As far as I have been able to tell it runs about 10 minutes every hour in 2-3 minute bursts. This is while hooked up to shore power when it will run full on at about 6 amps (it senses more than 13 volts on the 12 volt system). So that works out to about 24 amp hours a day. When it senses 12.8 volts or less it reduces current draw to 3 amps (ie when you are sailing). Not sure how this matters ... it would presumably have to run longer for same amount of cooling, but I have not paid close attention - this is a "feature". Suffice to say, I could reduce power required if I'd improve the oem insulation factor (lazy). But for me, just having a little fridge when the boat is mostly on the slip all summer is great. I can leave beers, apples, cheese, eggs, sausage etc and be ready to go for a day or two or three. But I've only got 2 group 27 AGMs and 200 amps / 100 effective so keeping the system on for more than a day or two cruising becomes problematic - except if I motor sail for a good part of a day. When I do take off for overnight, I'll load two bags of ice into the space, partly just to have cubed ice!!!!, then try to remember to snap the compressor on when/if motoring. I can gunkhole around quite nicely this way for the better part of a week, esp if I snag more ice or get some shore power for a night. If I lean a gallon of water up against the plate it will freeze it, but for the most part the space acts as a fridge now, but colder in the bottom, warmer on the little shelves

The water cooled coil is smart, built into my stbd cockpit scupper, and the compressor is basically silent (masked) if you have any wind or water noise at all - which when you think of it is what makes boats charming, and sometime perplexing, all those little sounds.

cheers

Edit: I think what I am trying to say is you can lower the “tech dependency” quotient by realizing you still have your good old ice box with the addition of cooling “sometimes”. But by all means if it’s convenient, pick up some block ice and continue as before …

Fred
That's great info. Really appreciate you sharing your observations on the system. Lots to think about.

John

[John Stone]

Fred
I looked up the 3751 sp. it seems to be a slightly more capable unit (for a bigger box) than the 3251 sp. I looked at the pictures. That's a very clean installation. Nice work.

How many cf is your box and why did you pick the 3751 vice the 3251?

[fmueller]

John,

You know what ... I have the smaller one. When I grabbed that link the other day it was hard for me to tell on the Defender site - I think maybe they are only stocking the lager 3751 - but looking at the Isotherm catalog now, I can see I got the 3251. Both of those have the same pump/compressor; just a bit larger plate in the 71. I remember thinking there was no way my CD 27 box was 7 cu ft. Probably not even 5 cu ft but close. I did put a tape into the box, but it's so irregular I just shrugged. The OEM ice box is very poorly insulated, but we improved it a little because we put Sounddown noise insulation all over the inboard surface of the ice box, mostly to damp engine noise, but also to keep just a little more engine heat away from the little "fridge".

It has worked really reliably, and has lots of hours on it because I typically just leave it running all summer when I leave my boat at the slip - which is most of the time - so it sits in there running just like a household fridge - ie all the time and Ive got cold water and better just waiting.

Interestingly, mussels and other sea life do not grow up inside in the exchanger coil and I think that's because it gets too warm for their biology. At one point the compressor started to make a bit of a buzzing noise and I thought - uh oh ! But on inspection I realized it had jumped a little on its suspension and was vibrating against one of the copper cooling hoses - maybe from rough seas ?? So I sort of re-centered it on its feet and the buzz promptly stopped and has not reoccured. It really is quiet.

I think with your super insulated little space this device would work great - best thing is its almost inaudible. Someone explained to me once that the plate is filled with the same gel that those blue freezer cubes have ... so the cold plate is acting like a lump of ice. In humid weather it gets pretty frosted up - not sure if that cuts efficiency, but shut it off for a day and thats gone.

BTW - I'm installing a Pelagic tiller pilot. Have you heard of them ??

Fred

https://www.dropbox.com/s/qiku6zeru0dag ... y.jpg?dl=0

[wikakaru]

...
As far as I have been able to tell it runs about 10 minutes every hour in 2-3 minute bursts. This is while hooked up to shore power when it will run full on at about 6 amps (it senses more than 13 volts on the 12 volt system). So that works out to about 24 amp hours a day. When it senses 12.8 volts or less it reduces current draw to 3 amps (ie when you are sailing). Not sure how this matters ... it would presumably have to run longer for same amount of cooling, but I have not paid close attention - this is a "feature".
...

That actually IS a feature. The faster the power is drawn from a battery, the less power can be drawn from the battery in total. So if your fridge can switch between running at either 3 amps for 20 minutes per hour, or 6 amps for 10 minutes per hour, the battery will last longer if the fridge is doing 3 amps for 20 minutes. When you have a high charging voltage, like when you are running the engine, having the fridge put as much cold into the box as quickly as possible while the engine is running, and having the fridge slowly sip energy when the engine isn't running is a really good idea. I didn't realize that fridge controllers had gotten that smart, but it makes perfect sense to me. If I were installing a new fridge today and had the choice between one that was smart like this and one that wasn't smart, I'd go for the smart fridge.

Smooth sailing,

Jim

[fmueller]

Good point Jim !

If there is an efficiency in these small Isotherm units a lot of it has to be due to the cooling coil immersed directly in seawater. That's what I thought was so, err, "cool" - no fan/heat exchanger/bulk necessary therefore one less motor draw, and less noise. The actual compressor is tiny. Also, the cold plate looked sturdy (it is) so that was another thing I took into consideration.

But no one I talked to said the cold plate was inherently more efficient than the evap plate versions, which can also be had with the thru hull coil. I think if you want a section of your box to be a "freezer" then one of the evap plate configs would be the way to go depending on the geometry of your box. I just wanted a "cooler" so to speak so got the plate.

cheers

another pix

https://www.dropbox.com/s/j0bof76565469 ... s.jpg?dl=0

[John Stone]

Good discussion. Anyone else?

Attached picture I found on a forum where the originator claims this is photo of his 3251 SP through-hull after 10 years of use. He stated he doesn't use the zinc.

[Jim Walsh]

I installed the zinc the first season….just in case….then I went one season without it. I installed the same zinc this year (it had just a hint of loss) for no logical reason. You never know when you may encounter a stray current from a neighbor or the wiring in your slip…..so it certainly won’t do any harm so equipped.