Refrigeration System - Always on power or battery switched power?

Ward H

Ward H

.
Nov 7, 2011
3,651
Catalina 30 Mk II Barnegat, NJ
I used to religiously turn off the battery selector switch when leaving the boat.
Now I have a new refrigeration component system, protected by a breaker on my DC panel, I've been leaving the battery switch on so my beverages stay cold.

Now I'm wondering I thought it necessary to always turn the battery selector switch to off. Any issue with leaving it on?
Should the refrigeration system be powered by always on power like a bilge pump? (of course it still needs to be protected by a circuit breaker)

Just wondering what others do.
 
Terry Cox

Terry Cox

.
Dec 25, 2000
5,735
Hunter Passage 42 Shelter Bay, WA
I keep our refrigeration on 24/7 and the battery selector switch is always kept on All/Both. Never been a problem since taking possession in 2002. I like my beer cold.
 
  • Like
Likes: NYSail and Ward H
FastOlson

FastOlson

.
Apr 8, 2010
1,953
Ericson Yachts Olson 34 28400 Portland OR
House bank is switched on, year around, and fridge is running 8 or 9 months and a major DC breaker is on for the bilge pumps. We are on shore power when not sailing, I should point out.
 
Ziggler

Ziggler

.
Jan 15, 2014
79
Morgan 323 Portland
My refrigeration is wired straight to the battery, so the main battery switch is turned off when notr aboard. I don't know why it is best practice to turn off the main switch, but I do.
 
D

dlochner

.
Jan 11, 2014
11,429
Sabre 362 113 Fair Haven, NY
Another leave the refrigerator on all the time. The only time I shut the main DC switch off is when I'm working on the DC Panel. If the DC wiring is done well and there is adequate circuit protection, there should be no issues with leaving it on.

Ziggler said:
My refrigeration is wired straight to the battery, so the main battery switch is turned off when notr aboard. I don't know why it is best practice to turn off the main switch, but I do.
Click to expand
How do you turn off the refrigerator? Is there a circuit breaker? One problem with this approach is overloading the battery terminal. Four connections per battery post is the limit.
 
Scott T-Bird

Scott T-Bird

.
Oct 26, 2008
6,081
Catalina 320 Barnegat, NJ
Funny, I was thinking about the same thing. I've been leaving my switch on all the time to keep the fridge running. I was looking at this Blue Sea Systems panel for a DCP switch. It appears to have two 24-hr circuits with 15-amp breakers (bilge & fridge?) and additional slots for anything else that you want connected directly to the house bank.

I think I will be installing this for just that reason.

Dual Battery Bank Management Panel - Blue Sea Systems

Offer simplified switching combined with main and 24-hour circuit protection.
www.bluesea.com www.bluesea.com
 
  • Helpful
Likes: Ward H
smokey73

smokey73

.
Oct 26, 2010
1,904
Hunter 40.5 Beaufort, SC
Scott T-Bird said:
Funny, I was thinking about the same thing. I've been leaving my switch on all the time to keep the fridge running. I was looking at this Blue Sea Systems panel for a DCP switch. It appears to have two 24-hr circuits with 15-amp breakers (bilge & fridge?) and additional slots for anything else that you want connected directly to the house bank.

I think I will be installing this for just that reason.

Dual Battery Bank Management Panel - Blue Sea Systems

Offer simplified switching combined with main and 24-hour circuit protection.
www.bluesea.com www.bluesea.com
Click to expand
You all must have very very reliable shore power or no chance of accidental (or dockmate intentional) disconnect or a heck of a house battery bank. Without Low Voltage Protection either in the power line to the refrig or within the refrig control circuit there is a real chance of taking your battery bank down to dead, which may not be recoverable or at least may degrade your battery. Is the amount of beer in the frig worth the battery replacement cost? I like my cold beer too but I'll drink it at room temp if in England or run out of cold beer.

The bilge pump on the other hand is vital to dewatering the boat and should be able to run when necessary even if it takes the battery to ground 0.

My 2 cents and probably worth that or less.
 
  • Helpful
Likes: Ward H
D

dlochner

.
Jan 11, 2014
11,429
Sabre 362 113 Fair Haven, NY
Scott T-Bird said:
Funny, I was thinking about the same thing. I've been leaving my switch on all the time to keep the fridge running. I was looking at this Blue Sea Systems panel for a DCP switch. It appears to have two 24-hr circuits with 15-amp breakers (bilge & fridge?) and additional slots for anything else that you want connected directly to the house bank.

I think I will be installing this for just that reason.

Dual Battery Bank Management Panel - Blue Sea Systems

Offer simplified switching combined with main and 24-hour circuit protection.
www.bluesea.com www.bluesea.com
Click to expand
I have that panel. Each bilge pump is on a separate circuit leading to the Blue Seas Bilge pump panel. The third position is used for the Propane solenoid/gas monitor.
 
  • Helpful
Likes: Ward H
D

dlochner

.
Jan 11, 2014
11,429
Sabre 362 113 Fair Haven, NY
smokey73 said:
You all must have very very reliable shore power or no chance of accidental (or dockmate intentional) disconnect or a heck of a house battery bank. Without Low Voltage Protection either in the power line to the refrig or within the refrig control circuit there is a real chance of taking your battery bank down to dead, which may not be recoverable or at least may degrade your battery. Is the amount of beer in the frig worth the battery replacement cost? I like my cold beer too but I'll drink it at room temp if in England or run out of cold beer.

The bilge pump on the other hand is vital to dewatering the boat and should be able to run when necessary even if it takes the battery to ground 0.

My 2 cents and probably worth that or less.
Click to expand
Yes, my shore power connection is good and reliable.

Yes, I have a good sized bank, ~460 ah. With nothing else running, it takes 4 to 5 days (depending on weather) to draw the battery down to 50% SOC. In most weeks I'm at that boat at least every 4 or 5 days.

The only time the bank was drained very low by the refrigerator is because somebody :rolleyes: turned the battery charger off. :banghead:

I'm on Lake Ontario, the temperature is generally lower here than in Charleston, so the refrigerator doesn't work as hard.
 
smokey73

smokey73

.
Oct 26, 2010
1,904
Hunter 40.5 Beaufort, SC
@dlochner - lucky you. Our water temp here in the summer was 90 with an air temp of 95 or more. Than again, I'm able to sail all year long :biggrin: I'll bring the cold beer on ice from home.

Still, a Low Voltage Relay seems like cheap insurance for those expensive batteries, but maybe you're frig has that built into it?
 
Ward H

Ward H

.
Nov 7, 2011
3,651
Catalina 30 Mk II Barnegat, NJ
@Scott T-Bird That's a very nice solution. I found it for $150, a very good price.

@smokey73 Yep, our sure power is not that reliable so a LVD will be installed this winter. I think my refrigeration control board has protection built in but I'm still going to install the Blue Sea LVD.

So, knowing now that it is common to leave the DC Panel powered on and since I already have it protected by a 100A breaker, I might be able to re wire to keep the two separate circuits the DCP provides and provide an emergency crossover if one bank should fail.

I love it, another possible wiring project to keep me busy this winter.
 
Ward H

Ward H

.
Nov 7, 2011
3,651
Catalina 30 Mk II Barnegat, NJ
OK, rub it in. You're allowed. :biggrin:
Of course you may find me on your doorstep some morning this winter, looking for a sail. :laugh:
 
DArcy

DArcy

.
Feb 11, 2017
1,704
Islander Freeport 36 Ottawa
smokey73 said:
You all must have very very reliable shore power or no chance of accidental (or dockmate intentional) disconnect or a heck of a house battery bank. Without Low Voltage Protection either in the power line to the refrig or within the refrig control circuit there is a real chance of taking your battery bank down to dead, which may not be recoverable or at least may degrade your battery. Is the amount of beer in the frig worth the battery replacement cost? I like my cold beer too but I'll drink it at room temp if in England or run out of cold beer.

The bilge pump on the other hand is vital to dewatering the boat and should be able to run when necessary even if it takes the battery to ground 0.

My 2 cents and probably worth that or less.
Click to expand
My fridge is connected through the battery switch and distribution panel. I leave my fridge on but in my case the shore power is the backup. I have 250 watts of solar which keeps my batteries full even while running the fridge. I only need a few hours of sunlight to keep it going but I do plug in my charger when I leave the boat at the dock in case there are a few cloudy days in a row. During the summer I am usually not away from the boat for more than 5 days at a time.

I am curious about the benefit of the Blue Sea Dual Battery Management Panel. The description says:
  • Isolates the Engine circuit from the House circuit
  • Allows emergency cross connect between isolated battery banks
  • Protects electronics from sags and spikes caused by engine cranking
A dual bank setup with engine start on one bank and house on the other with ACR to charge the engine battery from the house and 1/2/both switch should do the same. I have 2 Blue Sea Contura switch panels with built in fuses for my bilge pumps so maybe that negates the advantage of the built in 24 hr/always on of the above dual battery management panel.

No problems with too many connections on the battery terminals if you have a suitable bus bar.
 
FastOlson

FastOlson

.
Apr 8, 2010
1,953
Ericson Yachts Olson 34 28400 Portland OR
I am almost sure that our little Isotherm fridge is supposed to shut down if the voltage drops too much, but do not have the manual handy to confirm this. Anyone else read the small print in theirs?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,672
Canadian Sailcraft 36T Casco Bay, ME
Yep, our sure power is not that reliable so a LVD will be installed this winter. I think my refrigeration control board has protection built in but I'm still going to install the Blue Sea LVD.
Click to expand
This is the only safe way to do this. We see THOUSANDS & THOUSANDS of dollars in destroyed batteries each year because boat owners assume dock power is as reliable as you home's power. Nothing could be further from the truth, and with ground fault now being an NFPA/NEC requirement the problems of lost shore power are only getting worse.

As a marine electrician the only way I would ever plug into a marina is with an isolation transformer. I would never leave any DC devices turned on once I left the boat... There are a plenty of lucky n=1 folks out there, but when you work on boats for a living you get an entirely different perspective on marina power failures...
 
  • Like
Likes: LloydB
D

dlochner

.
Jan 11, 2014
11,429
Sabre 362 113 Fair Haven, NY
DArcy said:
My fridge is connected through the battery switch and distribution panel. I leave my fridge on but in my case the shore power is the backup. I have 250 watts of solar which keeps my batteries full even while running the fridge. I only need a few hours of sunlight to keep it going but I do plug in my charger when I leave the boat at the dock in case there are a few cloudy days in a row. During the summer I am usually not away from the boat for more than 5 days at a time.

I am curious about the benefit of the Blue Sea Dual Battery Management Panel. The description says:
  • Isolates the Engine circuit from the House circuit
  • Allows emergency cross connect between isolated battery banks
  • Protects electronics from sags and spikes caused by engine cranking
A dual bank setup with engine start on one bank and house on the other with ACR to charge the engine battery from the house and 1/2/both switch should do the same. I have 2 Blue Sea Contura switch panels with built in fuses for my bilge pumps so maybe that negates the advantage of the built in 24 hr/always on of the above dual battery management panel.

No problems with too many connections on the battery terminals if you have a suitable bus bar.
Click to expand
There's another recent thread on replacing a battery which has drifted into battery management and now solar.

If a Blue Sea DCP+ is installed it is important to have switches to completely isolate the start/reserve battery and the house battery. This is necessary if one bank should fail, it needs to be taken out of the system. A switch is faster and easier than a wrench.
 
You must log in or register to reply here.

Top Bottom