When to run the refrigerator?

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RPowers's picture
RPowers
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When to run the refrigerator?

I'm still trying to figure out all the features of this new (to me) boat.

1) When to run the fridge? With shore power only? When engine is running only?

2) Also, does the hot water heater heat water whenever shore power is connected?, and is there a way to switch off the hot water heating?

Thanks,

-Rick

Captain Rick Powers
(USCG OUPV)
1999 Catalina 36 mk II
Hull#1745
Std Rig, Fin Keel
Palo Alto, California

San Francisco Bay

StephenK's picture
StephenK
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Welcome Rick,

The hot water heater has a separate breaker on the AC side of the electrical panel...so if you want hot water, you will need to have shore power plugged in and the breaker in the "on" position. To turn off the hot water heater, you can switch the breaker to the "off" position. I turn "off" my hot water breaker while away from the boat.

As far as the refrigerator, you are probably going to get a range of responses. It will depend on how you want to use it, what you want to store in it and the amount of battery amp hours you have to run it.
I have a DC refrigerator and I keep mine "on" while away form the boat as I like to keep beer and condiments chilled and have the frig ready when we show up at the dock. (I do not keep it on the coldest setting while away form the boat). While on the boat, I do keep it towards the coldest setting. I should point out that we typically spend only 1 night out form the dock and I have 2 4d's as my "house" bank and a group 27 as my "reserve" battery.

Stephen Kruse
Kruse Control #1428
1995 C-36 MKII SR/WK
Lake Lanier, Ga.

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plaineolde
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I leave my fridge on all the time too, with the boat on shore power while I'm away. I keep a few items in the fridge which saves me bringing them every time. And I've found that it takes hours of continuous running for the fridge to get down to temperature, if it's left off, especially when the inside of the boat is 100+. I have the same battery setup as StevenK.

I also turn my hot water heater off when I leave the boat.

Enjoy your new boat..!

Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay

stu jackson c34's picture
stu jackson c34
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1. HW - while the standard Seaward water heater is reputed to have a thermostat on the electrical side, I never trust it. It takes less than half an hour to heat the 6 gallon tank on shorepower. I then turn it off. I strongly urge all of you to do the same, it's just safer.

RTFM - your boat manual, as to how the engine heats the hot water when the engine is running.

2. Fridge: two schools of thought a) run it all the time: Adv: stuff is cold, box stays colder; Disadv.: shorepower fails and ya got a mess of rotten mayonnaise in your fridge, the equipment simply doesn't last as long; b) don't use it unless you're on board: Adv.: machine lasts longer 'cuz it ain't your home refrigerator, it ain't that hard to bring a few things from home including a small zip lock bag of ice cubes (our A/B makes ice cubes within four hours); you can stop at a 7/11 and buy a cold six pack on the way to the boat or bring some from home; Disadv.: You have to remember to stop to buy the cold beer.:cool: Many folks freeze quart size jugs of water to help cool down the box, and use it for drinking water as it melts.

The fridge draws an average of 60 ah per day (5 amps running, usually 50% of the time once the box cools down) so with lights and everything else, most people with fridges budget 100 ah per day to size their electrical systems. If you have lots of LED lights you can cut your electrical use down, but could make up for it by watching TV or using a computer a lot - only YOU can make up and energy budget for how YOU use YOUR boat. [url]http://c34.org/bbs/index.php/topic,6353.msg41471.html#msg41471[/url] There's a link there to an energy budget example.

Also, do a search here or Google boat energy budget or get a good electrical book and learn about it. You don't need to wait to run your engine or use shorepower to run your fridge, 'cuz that's what STORAGE BATTERIES are made for.

The only guy I agreed with about running his fridge 24/7 had his home and office 20 yards away from his boat, and guess where he went for lunch and brain breaks? :rolleyes:

Your boat, your choice.

Congrats on your new boat, now you get to start reading, a LOT!:eek:

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

dejavu's picture
dejavu
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My fridge has been on for the past 12 years. No problem so far (knock on teak).

Mike

Deja Vu
1991 MK I # 1106
Marina del Rey, CA

plaineolde's picture
plaineolde
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I've run mine for 24x7 8 months out of the year for 13 years no issues. I did lose shore power on my pier once, which the marina owner didn't know about until I notified him. Yes, some spoiled mayo but fortunately the store is only 10 minutes away. He offered to pay for it but I didn't accept, was only about $20 bucks worth of stuff. Evidently the Adler Barbour units are pretty well made. When it does fail, I'm fairly certain I'll curse myself for leaving it on all the time, but I've found the trade off to be worth it.

Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay

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deising
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Lots of good comments already, Rick.

Being able to run your fridge off the batteries gives you ultimate freedom (as opposed to haing a cold-plate system with an engine-driven compressor like many Carribean charter boats. As mentioned, of course, it is ALL driven by how much battery storage you have, what your total engery budget is, and what options you have for recharging your batteries.

I can tell you from an early experience where we had a current drain that was not monitored (Prev owner failed to run a 5A load through the current-measuring shunt and I failed to note it - both bad), that trying to run the fridge with flat batteries (say, below 12.1 V) caused the compressor to cycle on an off frequently with little cooling effect.

Have a good battery bank and charging plan if you want a cold fridge on the hook. We do and it is great.

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

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Nimue
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I have two house banks of GC batteries, ie. 4 batteries, plus a starter. I don't leave my fridge on 24/7, because I think it must shorten the life of the fridge unit.

I do run it 24/7 when I'm on the boat. I ran it for 2 weeks straight a couple weeks ago and it was fine. This included one 4 day stay on the hook and off the grid. Everything seemed fine.

My dad has a similar setup in his boat and he usually turns the fridge off at night, but I think that is more because the compressor is right under his pillow in the aft cabin of his boat.

I should add that I do not have microwave, TV, blender, coffeemaker, or any of the other ridiculous electrical stuff that belongs in a house, so I have a lot of Ah in my budget.

Jason V
Vancouver, BC, Canada

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Rockman
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Posts: 237

We leave the fridge running. It is on 12V power, which is constantly being charged through the battery charger. We did leave the shore power off one weekend. After the fridge was left running all week on the batteries we still had 90% capacity (450Ahr of capacity).

As soon as we climb aboard, I flick on the hot water. Within a sort time, we have hot water!

Cat375 - Rock The Boat - Hull 54
Lake Macquarie - NSW - Australia

deising's picture
deising
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[QUOTE=Rockman;9570]After the fridge was left running all week on the batteries we still had 90% capacity (450Ahr of capacity).[/QUOTE]

Sorry, Rockman, but that doesn't seem right. Using 10% of 450Ah means your fridge consumed only 9Ah per day (assuming 5 weekdays running off batteries alone). The means it ran for approximately 2 hours per day.

That might be possible if the interior temperature of the boat was close to the thermostat setting, but I doubt that's what you mean.

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

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Rockman
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[QUOTE=deising;9576]Sorry, Rockman, but that doesn't seem right. Using 10% of 450Ah means your fridge consumed only 9Ah per day (assuming 5 weekdays running off batteries alone). The means it ran for approximately 2 hours per day.

That might be possible if the interior temperature of the boat was close to the thermostat setting, but I doubt that's what you mean.[/QUOTE]

Yes, I was amazed too. The 90% was taken off the voltage meter, so I am not sure how accurate this was. Plus the temperature during the week was very cool, so the fridge was not doing too much, and off course, it was not openned all week.

The efficency of modern fridges is improving. My Waeco portable used very little power.
I am about to install a new battery monitoring system - as a test of its usage. This will give us some idea on the battery life.

Cat375 - Rock The Boat - Hull 54
Lake Macquarie - NSW - Australia

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Capt. Sam
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I've just acquired my C36, hull 1327, in June. Been working on the boat in its slip alot lately and leaving the frig on 24/7. But I'm finding that when I go away for a couple of days and come back, the frig is not on, even though I left the switch on (I'm on constant shore power and my frig is 12v like all the above but running off the charger.) After I fiddle with everything, ie open the cockpit hatch where the frig is, flip the panel switch on and off a few times, the darn thing comes on, but lately seems to cycle back off.
Any ideas???

Capt. Sam Murphy
1994 Catalina 36, Hull 1327
Shoal draft, two cabin model.
Panama City, Florida

plaineolde's picture
plaineolde
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perhaps a dumb question, but does the fridge need to come on? What is the temperature in the box??? I have a regular refrigerator/freezer thermometer in mine so I can adjust the temp control to keep the box in the proper range.

Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay

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SailorJackson
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I got my 2005 C36 this spring and have been leaving the fridge running while I was gone. I got on the boat this weekend and found that the AC had become disconnected and the new AGM batteries were totally dead, down to about 8 volts. The fridge had taken it down over a period of days. If I had not left the fridge on the batteries would have been fine and the boat would have remained protected, to some degreee, by the bilge pump. As it was, the boat was dead with no DC and no bilge protection, plus the house batteries had suffered the sort of 100% cycle that they really don't like. UGH!

One other fridge question: When I got the boat the freon (or whatever it is these days) was out and I had a service tech recharge. The service tech was highly critical of the original installation because there was no insulation of the copper lines that carry the cooled compressed gas to the fridge evaporator. They build up with ice, cutting the cooling capacity, and then every time the compressor cycles they defrost and get the wooden shelf wet. It's going to rot out eventually. Anybody know where I can get the foam insulation the right size for the little copper pipes?

G. Jackson

Greg Jackson
SV Jacqui Marie
2004 C36, MKII
tall rig, wing keel,

windward1
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Posts: 146

Capt. Sam,
Many years ago my fridge was always warm when I got to the boat even though it was running fine when I had left. After having a lot of opinions, the problem was that the "black box" would not recycle the fridge back on once it cycled off. The box was replaced and it has worked fine ever since. I never turn it off unless I will be unplugged for more than a day. I have lined the fridge with insulation that has bubbles between aluminium foil which seems to help keep it cool.
Re Water heater:
I turn my water heater on for about a half hour and then turn it off at the panel. When I forget to turn it off, the reset button often pops and has to be reset. Of course you don't realize this untill the next time at the boat the hot water heater won't work.

Richard
1994 C36 Tall Rig M1.5
Waukegan Harbor
Lake Michigan

stu jackson c34's picture
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[QUOTE=SailorJackson;9649]I got my 2005 C36 this spring and have been leaving the fridge running while I was gone. I got on the boat this weekend and found that the AC had become disconnected and the new AGM batteries were totally dead, down to about 8 volts. ...UGH![/QUOTE]

This is what I referred to earlier as the "ruined mayonnaise syndrome." Oh, I forgot, it can kill an expensive set of batteries, too. Sorry it happened to you, GJ.

[QUOTE=SailorJackson;9649]One other fridge question: ...Anybody know where I can get the foam insulation the right size for the little copper pipes?[/QUOTE]

ACE Hardware should have a wide variety of pipe insulation. That's what's on our lines.

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

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plaineolde
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regarding discharged batteries; I've had the AC fail twice that I remember. The fridge is supposed to shut down if the voltage drops too low ; the manual says it needs "11 volts at start up, or it aborts" When I had an AC failure, the battery monitor low voltage alarm was sounding, the fridge had stopped (out with the mayo), and the batteries were about 11.8 volts. The monitor indicated a 50% discharge. My batteries are a pair of 4D gel cells that I installed in the spring of 2000 and are still going strong (somewhat of a miracle).

So I'm surprised that your batteries were so deeply discharged by the fridge; seems that it's supposed to shut itself down before that happens.

Gary and Cathy Price
1997 C36 Mk II Tall Rig/Wing Keel Imagine...
Hull # 1617
Worton Creek, Md.
Northern Chesapeake Bay

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Rockman
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[QUOTE=plaineolde;9664]The fridge is supposed to shut down if the voltage drops too low ; So I'm surprised that your batteries were so deeply discharged by the fridge; seems that it's supposed to shut itself down before that happens.[/QUOTE]

My fridge also shuts down when the voltage drops below a certain level. If you fridge is older and does not have this function, you can buy devices to perform this function (my old boat had a solar regulator that also performed this function).

Another good reason to have a two battery setup - with the fridge running off the house batteries.

Cat375 - Rock The Boat - Hull 54
Lake Macquarie - NSW - Australia

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