Ice Box Conversion

Apr 18, 2012
45
Catalina 400 MKI 67 LaSalle,Mi
We have a Nova Kool conversion with the freezer. The compressor is variable speed, If the engine or battery charger are on the compressor will cool the freezer quicker. Normally it draws about 2 amps and uses about 40 ah/day, slightly more if it gets hot out. Our old Cold machine drew 6 amps when running. The freezer is nice for long trips which we rotate freezer packs from the cooler to refreeze them.
 
Jan 7, 2011
4,726
Oday 322 East Chicago, IN
I love my fridge and consider it a huge improvement over my old icebox.

I always have cold beer on hand, have some ice in the little freezer in case I have a hankering for a Tanqueray and Tonic, etc.

Like the OP, I usually day sail, but can do an overnight or 2 on my 2 group 27’s.

You will love it!

Greg
 
Sep 15, 2013
707
Catalina 270 Baltimore
I added refrigeration to my ice box last august. It was the best upgrade I have done on the boat. No more hauling ice and dealing with the ice box after the cruise. I bought an Isotherm 2010 with the electronic control. My average is a 2 day cruise and I cannot detect any impact at all on my batteries. I have 2 FLA group 40s. Pay close attention to how big your box is and buy accordingly. Installation was a pleasant long afternoon. Also check your box carefully for openings along seams. I was getting a lot of condensation in the beginning. I found openings between the sides and the top of the box. After sealing them the condensation went away. Keep a close eye on Defender. They put the Isotherm units on sale regularly. I got mine for under $800. Go for it! You will be glad you did. You can PM me if you have any questions.
 
Sep 15, 2013
707
Catalina 270 Baltimore
One of the newer energy efficient units should work for you perfectly. The power drain in a box your size and your climate will be nowhere near 50Ah/day. In hotter Minnesota my Isotherm ISEC unit draws about .5A per hour. Best (non performance) mod we’re ever made to the boat.

More here:

http://rarerarebird.blogspot.com/2017/06/refrigeration.html
Agreed! The smart Isotherm units are super efficient. If your electrical system is reasonably healthy you should have no trouble whatsoever. I can honestly say my fridge does not have any appreciable impact on my electrical system and I have less battery capacity. Also the above blog helped motivate me to make the move to refrigeration.
 
Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
I pulled the trigger on a Isotherm 2010 with ISEC from Defender for $764. I would have preferred a oval evaporator but they don't offer them with ISEC and to add it would be another $120.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
I pulled the trigger on a Isotherm 2010 with ISEC from Defender for $764. I would have preferred a oval evaporator but they don't offer them with ISEC and to add it would be another $120.
Sounds like a nice unit, but oh, the marketing hype
  • The device not only makes your fridge intelligent but also allows the storage of a significant amount of cold energy into the loaded food and drinks
There is no such thing as cold energy, cold is the absence of energy.
  • The cooling energy is stored when a power surplus is available (engine on or connection to grid) and reused first..,
Loosely translated, when system voltage is high due to motoring or connected to shore power, the food is chilled to a temperature below the typical 38* but not so cold that the beer freezes. This allows the temperature rise 6 to 8 degrees before the unit comes back on. If only on battery power, it keeps the food slightly warmer probably at 38*. Saves on battery power. Smart feature, poor marketing hype.

Anyway, Webasto has a good reputation. Enjoy your cold beer this summer and do monitor the SOC of your batteries so you don' t get left out in the heat.
 
Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
Sounds like a nice unit, but oh, the marketing hype
  • The device not only makes your fridge intelligent but also allows the storage of a significant amount of cold energy into the loaded food and drinks
There is no such thing as cold energy, cold is the absence of energy.
  • The cooling energy is stored when a power surplus is available (engine on or connection to grid) and reused first..,
Loosely translated, when system voltage is high due to motoring or connected to shore power, the food is chilled to a temperature below the typical 38* but not so cold that the beer freezes. This allows the temperature rise 6 to 8 degrees before the unit comes back on. If only on battery power, it keeps the food slightly warmer probably at 38*. Saves on battery power. Smart feature, poor marketing hype.

Anyway, Webasto has a good reputation. Enjoy your cold beer this summer and do monitor the SOC of your batteries so you don' t get left out in the heat.
Yea, I call it verbal judo. Tamato, Tomato.
 
Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
Sounds like a nice unit, but oh, the marketing hyp
  • The cooling energy is stored when a power surplus is available (engine on or connection to grid) and reused first..,
This is why I wanted a oval evaporator to store water bottles in the middle of it so they would freeze and I can move them to the main area. I'm also going to get a battery powered fan for the frig. I had one in my RV frig and it worked great while working on only a D cell.
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
After changing from a decade with an L-shape evaporator to a new system with a box shape (i.e. "oval") evaporator in order to have a little place to potentially keep frozen goods, we are not 100% pleased with the change. We still keep the whole nterior at about 38 to 40 degrees for the open area. The interior of the little 'oval' will slush the water, but not usually freeze it solid.
Speculation on my part, but it appears that wrapping the coolant channels around the box shape has reduced the effect for the rest of the compartment a bit. We used to be able to (inadvertently!) freeze the whole compartment by turning the thermostat down a notch too low.
Our power usage seems to be about the same as the former system and everything is kept cooled enough, but we sort of hoped to be able to have a frozen steak tucked away for a couple of weeks later when out cruising.
I thought that the channels on the inside of the little 'oval' would freeze that area very well, but perhaps I am not understanding the whole system and the dynamics.
Anyhow, we still love the fridge, but have had to dial down our expectations of what the enclosed evaporator is capable of.
 
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Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
After changing from a decade with an L-shape evaporator to a new system with a box shape (i.e. "oval") evaporator in order to have a little place to potentially keep frozen goods, we are not 100% pleased with the change. We still keep the whole nterior at about 38 to 40 degrees for the open area. The interior of the little 'oval' will slush the water, but not usually freeze it solid.
Speculation on my part, but it appears that wrapping the coolant channels around the box shape has reduced the effect for the rest of the compartment a bit. We used to be able to (inadvertently!) freeze the whole compartment by turning the thermostat down a notch too low.
Our power usage seems to be about the same as the former system and everything is kept cooled enough, but we sort of hoped to be able to have a frozen steak tucked away for a couple of weeks later when out cruising.
I thought that the channels on the inside of the little 'oval' would freeze that area very well, but perhaps I am not understanding the whole system and the dynamics.
Anyhow, we still love the fridge, but have had to dial down our expectations of what the enclosed evaporator is capable of.
I've seen them with plastic covers they would probably help with the freezing. Take a look at Camping World for the refer fans. They worked well.
 
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Feb 26, 2004
22,760
Catalina 34 224 Maple Bay, BC, Canada
FWIW - Our "oval" evaporator keeps stuff frozen. I make ice cubes in the vertical trays. I have two trays. Never an issue in 20 years.
 
Last edited:
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
FWIW - Our "oval" evaporator keeps stuff frozen. I make ice cubes in the vertical trays. I have two trays. Never an issue in 20 years.
I may have to experiment with dialing it down a wee bit further, and see if the metal cover is fitting as well as possible.

I also found a picture of our remote readout temp. device which was sourced from Camping World.
 

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RoyS

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Jun 3, 2012
1,739
Hunter 33 Steamboat Wharf, Hull, MA
Your freezer compartment needs to be either vertical with a closed bottom without a door on top or be horizontal and have a door. Some fridge control thermostats sense fridge temperature in the box while others sense temperature in the freezer.
 
Apr 8, 2010
1,942
Ericson Yachts Olson 34 28400 Portland OR
Your freezer compartment needs to be either vertical with a closed bottom without a door on top or be horizontal and have a door. Some fridge control thermostats sense fridge temperature in the box while others sense temperature in the freezer.
Our system T-stat tube is clipped to the evaporator per the install instructions, and I see that I might need to seal the four little openings in the bottom of the stock evaporator housing... to sort of allow it to 'fill up' with colder air.
It occurs to me, a bit late, that I should also check directly on the temp. inside the "oval" by parking the transmitter in there. Obvious, suddenly!
:)
The compartment is vertical, and their install instructions said to put the little flip up door on it. I might also want to revisit that idea, too.
 
Dec 28, 2015
1,837
Laser, Hunter H30 Cherubini Tacoma
Ordered two 100watt solar panels to mount on my davits and a controller. Should be a good start.
 
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Sep 24, 2018
2,549
O'Day 25 Chicago
As a reference, a small mini fridge draws about 1/2 amp @ 120v. The one I have is about 5 years old and cost about $50 from Walmart
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
As a reference, a small mini fridge draws about 1/2 amp @ 120v. The one I have is about 5 years old and cost about $50 from Walmart
That is 10 times the wattage drawn by an efficient DC refrigeration unit.