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Ice Box Conversion

Dec 28, 2015
476
Laser, Hunter H30 Standard Tacoma
I'm looking at adding frig/freezer to my existing ice box. This is my thought process;
-add insulation as needed to the existing box as well as a lid seal.
-install a freezer capable conversion unit, air cooled but probably with the newer electronic controlled system like what Isotherm offers for power efficiency
- later install enough solar panels to my hard dodger and davets to run the system.

I use the boat mostly for day sailing but plan on weekend trips with a couple week long trips with the fam. We have been a camping family in the past with campers/motorhomes and I was informed that refrigeration is required by the boss. I currently have a 4 battery (lead acid/deep cycle) coach bank and a large inverter (can't remember the size but it will run the microwave). Engine alternator is aftermarket and I believe a 44 amp unit.
I am pondering the freezer option to leave the unit on when in slip with several gallon jugs of water frozen to keep the box cold when day sailing and supplement the refer system when out for longer to keep the run time down.
This seams to make sense. Whats your thoughts and what brand do you recommend? It seams Isotherm is the leading brand with Norcold being in the lower.
 
Jan 11, 2014
4,057
Sabre 362 113 Fair Haven, NY
The big issue with refrigeration is having the power to run it. Refrigeration can easily consume 50+amphours a day. Will your battery bank be able to handle it? Will you be able to recharge your batteries? If in deed your alternator is 44 amp, it probably won't be big enough to keep your bank reasonably charged for a week long trip. If it is a stock internally regulated alternator, it won't be able to keep your house bank up, unless you motor a lot. What kind of batteries do you have and how old are they? What kind of battery charger do you have?
 
Jul 23, 2009
176
Beneteau 88 First 285 Grand Lake, Oklahoma
Unless you really need the freezer skip it. On those week long trips just bring an ice chest with you, you'll likely need it anyway. I wouldn't leave the cooling unit set to max cold just to freeze water jugs, in a poorly insulated box it could take a long time putting an unnecessary load on the cooling unit and the electrical system. Bring the ice from home.

I do love having a fridge on-board! No week long trips for me but I do always have cold beer at the ready. Adding the unit itself wasn't that difficult. Do your research. I used an air cooled unit. Make sure you plan for air flow into and out of the cooling unit. I used the bilge area as part of the air supply and my bilge stays dryer now.
 
Dec 28, 2015
476
Laser, Hunter H30 Standard Tacoma
The big issue with refrigeration is having the power to run it. Refrigeration can easily consume 50+amphours a day. Will your battery bank be able to handle it? Will you be able to recharge your batteries? If in deed your alternator is 44 amp, it probably won't be big enough to keep your bank reasonably charged for a week long trip. If it is a stock internally regulated alternator, it won't be able to keep your house bank up, unless you motor a lot. What kind of batteries do you have and how old are they? What kind of battery charger do you have?
I'm going to head to the marina sometime this week. I'll get you all the details when I do. thanks.
 
Jun 1, 2007
202
O'Day 322 Mt.Sinai
A friend of mine converted his 322 ice box into a refridge/freezer. I saw it and it looks great. It's on my to-do list. He added 2 60 watt solar panels to drive an Isotherm Compact Classic 2501 unit. He placed the compressor next to the ice box under the sink. It's very small, and he loves it. The evaporator in the ice box is oval shaped and inside it acts like a freezer. The rest of the ice box is the fridge. Goes for about a grand. Not cheap, but nice!

here's a link to it from West:
https://www.westmarine.com/buy/isotherm--compact-2501-refrigeration-system-kit--14995476
 
Apr 18, 2012
40
Catalina 30TRWK LaSalle,Mi
We put a Nova-Cool freezer plate last year, It draws 2 amps and runs at about a 40% duty cycle. There is a module that when it senses a higher voltage will increase the compressor speed for faster cooling. On longer trips we rotate the cold packs from the cooler to the freezer.
 
Jun 3, 2012
546
Hunter 33 Bay Pointe, Quincy
Beer puts a heavy load on your electrical system. If you add six warm beers every day to your fridge, expect the compresssor to run continuously all night to cool it down. You may find that upgrading your battery and charging capacity to support the cold beer will cost more than the fridge conversion did.
 
Nov 8, 2010
10,554
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
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
 
Dec 25, 2000
3,863
Hunter Passage 42 Shelter Bay, WA
Apr 8, 2010
1,136
Ericson Yachts Olson 34 Portland OR
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
I installed a new Isotherm kit about two years ago to replace a decade-old system that had developed fatal coolant leaks.
As with your setup, it is very efficient. I typically run the fridge and lights and all for two days at anchor and then start the diesel with power to spare. We do have a larger house bank -- two golf cart batteries. We never seem to go below about 12.5 v.
These modern fridge systems are almost a "miracle" compared to the standard stuff of twenty years ago!
:)
 
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Dec 28, 2015
476
Laser, Hunter H30 Standard Tacoma
The big issue with refrigeration is having the power to run it. Refrigeration can easily consume 50+amphours a day. Will your battery bank be able to handle it? Will you be able to recharge your batteries? If in deed your alternator is 44 amp, it probably won't be big enough to keep your bank reasonably charged for a week long trip. If it is a stock internally regulated alternator, it won't be able to keep your house bank up, unless you motor a lot. What kind of batteries do you have and how old are they? What kind of battery charger do you have?
I have 4 81amp/hour batteries. They are Interstate Deepcycle 24's 550 CCA, 690 MCA about 3 years old. I forgot to take a look at the alternator. The inverter/charger is a Freedom 10 which will charge up to 50 amps but that is with AC obviously. It has a remote control panel that allows equalizing the batteries.
 
Dec 28, 2015
476
Laser, Hunter H30 Standard Tacoma
I did some poking around the ice box to get a better idea of its insulation. There is a 3inch thick piece of closed cell foam on the lid so I figured there might be some added foam to the box. When I bought the boat I found a painted plywood panel was a little strange that made up the wall on the ice box side. The cabinet is between the box and engine compartment. It houses the water intake and strainer for the engine and sink through hull. What I found is that the area around the ice box was boxed off with the original cabinet forward of it, the cabinet wall I described and another panel aft. There is obvious foam residue in all of the cracks and it appears that the whole area was filled with foam. The counter top was replaced with Corian and I think this mod took place when the counter tops where off. So thats a plus! I need to do a little sealing and insulating on the underside of the countertop within the icebox, add a gasket to the lid and figure out a plan for the drain.
 
Jan 11, 2014
4,057
Sabre 362 113 Fair Haven, NY
I have 4 81amp/hour batteries. They are Interstate Deepcycle 24's 550 CCA, 690 MCA about 3 years old. I forgot to take a look at the alternator. The inverter/charger is a Freedom 10 which will charge up to 50 amps but that is with AC obviously. It has a remote control panel that allows equalizing the batteries.
Mike, here's a link to an article on Deep Cycle batteries. I think you will find it informative.
https://marinehowto.com/what-is-a-deep-cycle-battery/
Let's do some math.

If all 4 batteries are wired as one bank in parallel, you have at best 324 ah capacity. Following the general rule of not going below 50% SOC you potentially have 160 ah available for all your power needs. Realistically, if you are out from more than a day, the SOC will vary between 50% and 80% that will provide about 90 ah for daily use if you are able to recharge the batteries to 80% SOC.

The refrigerator's efficiency and how it is used will play a big role. Chilling the refrigerator while on shore power, pre-chilling or freezing food that goes in the refrigerator, and supplementing with ice will all reduce the energy demands and make this a more viable project. Adding a large freezer section will increase the energy demand, so it may be best to skip the freezer and stay with a refrigerator only.

When you consider recharging while motoring, take a look at this article on OEM alternators and battery charging:
https://marinehowto.com/automotive-alternators-vs-deep-cycle-batteries/

I don't want to dissuade you from installing refrigeration, it nice to always have cold beer on board, just be realistic in your expectations. A high efficiency refrigeration unit to keep cold food cold is viable, especially if other steps are taken to reduce energy consumption. Keeping cold food cold takes less energy than making warm food cold. A day or two away from shore power will probably work. A week, probably not.

One addition to your electrical system should be a SOC gauge like this one: https://shop.marinehowto.com/products/balmar-smartguage or the newer version of the SG. Monitoring the SOC will be important so you don't wake up one morning on anchor with dead batteries.
 
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Jul 1, 2010
674
Seaward 25, Catalina 350 Ithaca, NY
We put an Isotherm cold plate system in our Seaward 25 a couple of years ago. Works well and is very efficient. I beefed up the insulation as well as I could on our ice box, but it isn't ideal. That said, I turn on the fridge in the spring and turn it off in the fall. No shore power. All on 160 watts of solar. My recommendation is to add solar to your charging mix, and you won't have any issues. Of course, your biggest bang for the buck will be adding insulation to the box.
 
Dec 28, 2015
476
Laser, Hunter H30 Standard Tacoma
We put an Isotherm cold plate system in our Seaward 25 a couple of years ago. Works well and is very efficient. I beefed up the insulation as well as I could on our ice box, but it isn't ideal. That said, I turn on the fridge in the spring and turn it off in the fall. No shore power. All on 160 watts of solar. My recommendation is to add solar to your charging mix, and you won't have any issues. Of course, your biggest bang for the buck will be adding insulation to the box.
Is it the ASU model with the freeze pack or the traditional freeze plate
 
May 20, 2016
2,793
Catalina 36 MK1 Everett, WA
You don’t need an icebox conversion Just move to the PNW. Your cockpit will be a great frig.
 
May 20, 2016
2,793
Catalina 36 MK1 Everett, WA
Lets hope. I left Everett Tuesday at 2pm. Right now in Fossel Bay Sucia. Out for two weeks. And finally got most of the ice and snow off the boat.