Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-15-2019, 07:24 PM   #1
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
fridge - cooling only on batteries

Got to the boat a couple days ago after about 4 months away. Boat was at a very nice marina connected to shore power.
Upon opening the refrigerator I noticed that it was not cool at all.

Just as an experiment I tried running it off the 12 volt side and it cools perfectly.

Fridge is a 17 year old isotherm under counter unit.

Seems to me that it would make more sense for the fridge to work on 120v and NOT on 12v.

Any ideas on a simple fix, or is a replacement in my future? Since it has had a nice long life, I'm fine replacing if necessary. Any brands to stay away from?

Thanks as always.
__________________
Advertisement

bobbyp is offline   Reply With Quote
Old 07-15-2019, 08:18 PM   #2
Guru
 
syjos's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 601
Some boat refrigerators have 12 volt compressors and use a converter to run on 120 VAC.

If it runs fine on 12 volt then you need to replace the converter only.

If it was mine, I would run it from 12 VDC and have the battery charger replenish the battery and not waste money on a redundant converter.

My Seafreeze refrigerator was ordered to run on 12 VDC only - no converter.

The Isotherm, I believe, uses a Danfoss type rotary compressor and they last a very long time. The Danfoss compressor on our Seafreeze has been running for 19 years with no issues.
__________________

syjos is online now   Reply With Quote
Old 07-15-2019, 08:53 PM   #3
Guru
 
ben2go's Avatar
 
City: Upstate,SC
Country: USA
Vessel Name: Caroliner
Vessel Model: 28' Spira San Miguel
Join Date: May 2012
Posts: 2,253
I concur with syjos.
__________________
What a pain in the transom.

ben2go is offline   Reply With Quote
Old 07-15-2019, 08:59 PM   #4
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 7,316
I would agree with running it on 12 VDC for the future.

As it's 19 years old, I would start hunting for the replacement. It's a lot easier to shop and be objective when you food is still cold.

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 07-15-2019, 08:59 PM   #5
Guru
 
rochepoint's Avatar
 
City: Sidney BC
Country: Canada
Vessel Name: RochePoint
Vessel Model: 1985 Cheer Men PT38 Sedan
Join Date: Apr 2009
Posts: 1,445
Our fridge runs 24/7/365, it is only 12 volt direct off the batteries and the charger looks after the batteries. This is what was suggested by the manufacturer.........
__________________
Cheers Mike Barge
RochePoint
Sidney, British Columbia
Yes, I have my "AnchorRight"
rochepoint is online now   Reply With Quote
Old 07-15-2019, 09:47 PM   #6
Guru
 
syjos's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 601
The 12 VDC Danfoss compressor will not suddenly quit. It will start making a little noise that will gradually get louder when it's ready to replace and the compressor may take longer to cool the frig. I've seen Danfoss compressors run 1 to 2 years after the noise starts.

If the compressor is not a genuine Danfoss, there are imitation or knockoff compressors that look just like a Danfoss, can't tell you what it's behavior will be in it's final stages.

The Danfoss compressor is a dependable compressor that will outlast most other compressors, especially more than the Norcold swing compressor which has a 7 to 10 year life before they get noisey and run continuously without cooling much.
syjos is online now   Reply With Quote
Old 07-15-2019, 10:00 PM   #7
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
I guess this means it is a native DC compressor with a converter to change incoming AC to DC? I really thought it would work in the opposite direction but this makes sense considering all boats have some sort of DC power.



And based upon this:
https://www.indelwebastomarine.com/f...pare-parts.pdf , this is the replacement module:
http://www.isotherm-parts.com/isothe...50-compressors


Not sure my boat is smart enough to run the fridge off of battery power if I'm away for a week without totally killing the batteries. I believe I had that happen at the dock a couple years back.
bobbyp is offline   Reply With Quote
Old 07-15-2019, 10:43 PM   #8
Guru
 
syjos's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 601
As long as the capacity and the voltage match, you do not have to buy an Isotherm compressor. I'm sure Isotherm buys the compressors and private labels them.

Talk to a Danfoss distributor or a marine refrigeration shop and they should have a replacement at less cost maybe than Isotherm. Dave at Seafreeze - seafreezeinc.com is a Washington State marine refrigeration specialist. You might not buy from him but he could refer someone in your area.

Is your compressor hard plumbed or does it have quick connectors? That will determine installation. My Danfoss is connected with quick connectors which allows me to replace my compressor with a pre charged compressor without pulling vacuum and refilling the refrigerant.

If no quick connectors, a refrigeration tech. will be required.

I would not do this but 120 VAC rotary compressors are about half the cost of 12 VDC compressors. The AC compressor will operate off the inverter but you will experience higher 12 volt usage because of the inverters conversion loss.
syjos is online now   Reply With Quote
Old 07-15-2019, 10:48 PM   #9
Senior Member
 
City: Clearwater, FL
Country: United States
Vessel Name: Seas the Bay
Vessel Model: Hardin Europa
Join Date: Aug 2016
Posts: 423
If I look at that model number, that "1" in the middle suggests to me that this is a DC-only unit, i.e.

1130 = Cruise 130 line
BA = Drink model (no freezer)
1 = DC-only

The text of the sticker also suggests to me that it is DC only, e.g. 12/24V.

So....if I had a wild guess, I'd guess that this is a DC-only unit to which Isotherm's optional AC/DC module (Part number: z999/561) was added. This module converts 120VAC power into 24VDC and, once wired in, automatically switches between the battery DC source and the 120VAC-derived 24VDC source, preferring the 120VAC-derived 24V, when available.

-- http://www.isotherm-parts.com/isothe...c-dc-converter
-- https://www.defender.com/product.jsp?id=825933
-- https://www.fisheriessupply.com/isot...erter-z999-561

This module will automatically convert AC power to 120V power and switch the unit from battery-based 12V to 24V derived from the AC source when AC is available.

So, my guess is...that the AC/DC module isn't working and needs to be fixed or replaced.

You could just order a new one. But, before doing that, I'd check the simple stuff. I'd see if there is a fuse on either or both sides of it. I'd check its connections at the terminal block, etc. I'd see if there is something internal that can be repaired. Etc.
gkesden is offline   Reply With Quote
Old 07-15-2019, 11:07 PM   #10
Guru
 
syjos's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 601
Quote:
Originally Posted by bobbyp View Post


Not sure my boat is smart enough to run the fridge off of battery power if I'm away for a week without totally killing the batteries. I believe I had that happen at the dock a couple years back.
Don't you have a battery charger to keep the battery topped up?
syjos is online now   Reply With Quote
Old 07-15-2019, 11:12 PM   #11
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
Quote:
Originally Posted by syjos View Post
Don't you have a battery charger to keep the battery topped up?
I was at a marina that had electrical issues where being out of power for a few days wasn't something that was a very high priority. Learned not to keep anything perishable in the fridge.
bobbyp is offline   Reply With Quote
Old 07-15-2019, 11:14 PM   #12
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
Quote:
Originally Posted by gkesden View Post
If I look at that model number, that "1" in the middle suggests to me that this is a DC-only unit, e.g.

1130 = Cruise 130 line
BA = Drink model (no freezer)
1 = DC-only

The text of the sticker also suggests to me that it is DC only, e.g. 12/24V.

So....if I had a wild guess, I'd guess that this is a DC-only to which Isotherm's optional AC/DC module (Part number: z999/561) was added. This module converts 120VAC power into 24VDC and, once wired in, automatically switches between the battery DC source and the 120VAC-derived 24VDC source, preferring the 120VAC-derived 24V, when available.

-- http://www.isotherm-parts.com/isothe...c-dc-converter
-- https://www.defender.com/product.jsp?id=825933
-- https://www.fisheriessupply.com/isot...erter-z999-561

This module will automatically convert AC power to 120V power and switch the unit from battery-based 12V to 24V derived from the AC source when AC is available.

So, my guess is...that the AC/DC module isn't working and needs to be fixed or replaced.

You could just order a new one. But, before doing that, I'd check the simple stuff. I'd see if there is a fuse on either or both sides of it. I'd check its connections at the terminal block, etc. I'd see if there is something internal that can be repaired. Etc.
Thanks, I'll pull the refrigerator and see how it is wired up.
bobbyp is offline   Reply With Quote
Old 07-15-2019, 11:22 PM   #13
Senior Member
 
City: Clearwater, FL
Country: United States
Vessel Name: Seas the Bay
Vessel Model: Hardin Europa
Join Date: Aug 2016
Posts: 423
bobby.p,

I somehow missed the bottom of your post below that picture. If that is the AC/DC model (vs DC-only), it has that module built-in. And, I think you've hit the right part (but it looks DC-only with add on module to me).

Before I'd buy it, or the add-on version of the AC/DC module I noted, I'd do exactly as you suggest and pull the unit and look. If it is external, check the model number on the sticker. If it is internal -- do the same. There should still be a sticker on it. And, if not, look for one on the compressor to double check compatibility.

If all else fails, call them or the dealer for the right part number. With the model and serial number, they should be able to tell you which part for sure.

In any case, the unit, internally, is primarily a DC unit, and there is a module that does the AC->DC conversion and switching. This module is most likely the culprit and getting the right one is the only trick.

And, even then, a quick look and phone call isn't too much of a trick. You'll have to pull the unit to put it in anyway, so it is worth it to get the right part.

And since that is what you are doing...you seem to be on exactly the right path. Good luck!
gkesden is offline   Reply With Quote
Old 07-15-2019, 11:28 PM   #14
Guru
 
syjos's Avatar
 
City: Gig Harbor
Country: USA
Vessel Name: Sandpiper
Vessel Model: Bluewater 40 Pilothouse Trawler
Join Date: Nov 2012
Posts: 601
Quote:
Originally Posted by bobbyp View Post
I was at a marina that had electrical issues where being out of power for a few days wasn't something that was a very high priority. Learned not to keep anything perishable in the fridge.
If your dock power goes out, so does the AC frig.

On DC, it will continue running, duration depends on size of battery bank and when AC comes back on.
syjos is online now   Reply With Quote
Old 07-15-2019, 11:57 PM   #15
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
Quote:
Originally Posted by syjos View Post
If your dock power goes out, so does the AC frig.

On DC, it will continue running, duration depends on size of battery bank and when AC comes back on.
That is exactly what happened, fridge switched to DC power and my batteries went down to an unrecoverable voltage. Marina was crappy in all ways except for the staff but has a fabulous location and a waiting list measured in years.
bobbyp is offline   Reply With Quote
Old 07-18-2019, 06:42 AM   #16
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,348
"I was at a marina that had electrical issues where being out of power for a few days wasn't something that was a very high priority."

Wait till winter knocks out the power , it can be weeks!

Sounds like 79th street marina?
FF is offline   Reply With Quote
Old 07-18-2019, 08:05 AM   #17
Guru
 
O C Diver's Avatar
 
City: Fort Myers, FL... Summers in Crisfield, MD
Country: USA
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 7,316
Quote:
Originally Posted by bobbyp View Post
That is exactly what happened, fridge switched to DC power and my batteries went down to an unrecoverable voltage. Marina was crappy in all ways except for the staff but has a fabulous location and a waiting list measured in years.
One of the positives of an AC only refrigerator running through an inverter is that when you lose dock power it maintains the refrigerator through the inverter off the batteries; when the batteries go below a minimum voltage (user setable on better units) the inverter shuts off, keeping the batteries from reaching an unrecoverable voltage.

Ted
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
O C Diver is offline   Reply With Quote
Old 07-18-2019, 03:31 PM   #18
Guru
 
wkearney99's Avatar
 
City: Bethesda, MD
Country: USA
Vessel Name: Solstice
Vessel Model: Grand Banks 47 Eastbay FB
Join Date: Feb 2018
Posts: 849
Quote:
Originally Posted by gkesden View Post
So, my guess is...that the AC/DC module isn't working and needs to be fixed or replaced.
I concur. We had a unit like that in a previous boat, it would randomly refuse to keep chilled when on shore power. As in, it'd sense shore power AC and 'switch over' to using it... but not actually keep cold. If shore power was disconnected, it'd pull from 12v and chill properly.

But this is problematic in that without shore power (like when unattended during the week) that would lead to running down the house battery bank, which was woefully undersized for our needs anyway.

A refrigerant leak developed and while it was out for that I had the board replaced and that seemed to solve the problem. After that we kept the 12v breaker to it OFF most of the time, to avoid battery issues. If we didn't have shore power or generator AC we treated it more like a cooler, and limited how often we opened it.

I never did get around to installing a voltage cut-off switch. We just learned to live with it instead.
__________________
-- Bill Kearney
2005 Eastbay 47 FB - Solstice
wkearney99 is offline   Reply With Quote
Old 07-19-2019, 06:12 AM   #19
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,348
"One of the positives of an AC only refrigerator running through an inverter is that when you lose dock power it maintains the refrigerator through the inverter off the batteries; when the batteries go below a minimum voltage (user setable on better units) the inverter shuts off, keeping the batteries from reaching an unrecoverable voltage. "


YES YES YES!
FF is offline   Reply With Quote
Old 07-19-2019, 08:50 AM   #20
Veteran Member
 
City: NYC, NY
Country: US
Join Date: Jun 2018
Posts: 59
Quote:
Originally Posted by FF View Post
"One of the positives of an AC only refrigerator running through an inverter is that when you lose dock power it maintains the refrigerator through the inverter off the batteries; when the batteries go below a minimum voltage (user setable on better units) the inverter shuts off, keeping the batteries from reaching an unrecoverable voltage. "


YES YES YES!
Exactly the reason we keep the 12v fridge breaker off when leaving the boat. Also FF, you are correct, that was the 79th Street Boat Basin - great staff, location is 5 minute walk home but the boat gets constantly pounded even with lots of big fenders and sometimes dangerous just walking on the floating docks when the waves come in.

I found a troubleshooting document in my papers, tested it and found the converter is only outputting around 10v when running in shore power/generator mode so will be ordering one of these for next time we are at the boat.

http://www.isotherm-parts.com/isothe...c-dc-converter

BTW, unit documentation says that it has a cutoff when DC power gets to 10(?) volts, but that is pretty low and it didn't seem to work last time.



__________________

bobbyp is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 11:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012