Fridge Question - 110V to 12VDC

jme097

OK guys, my fridge down below in my 280 worked fine last year both shore power and 12VDC. I have noticed this year it will only work when connected to shore power and not on 12V but my cockpit fridge stills runs on both just fine. Is there a module or controller of some sort on the fridge that allows it to run on 12VDC? I am just curious as to where I should start my troubleshooting.  Thanks fellas

Stodge

I want to say it depends on the fridge.  My galley fridge has both AC and DC but my cockpit fridge is DC only.  If I recall the dual power types have separate inputs for power.  I'd start where the 12V DC connects to the fridge, make sure you have power there.  If not, trace back.  If you do have power there then your fridge may need some attention.  It should switch between AC and DC automatically.

Liberty44140

Both my galley and cockpit fridges are AC and DC (when AC is not connected). Agree that you should pull the fridge and you will quickly see the AC and the DC inputs. Easy to see if 12v is coming in to the fridge or not. There is a fuse on the panel. 

jme097

Thanks guys! 

Cableguy Greg

Both of my fridges work on AC and DC. There must be a control module on the fridge because I can here it click when I shut off the shore power. I assume that you have the same Waeco fridges that I have. If so, you will probably have to pull it out to see what is going on with it.

jme097

@Cableguy Greg thats what my Friday night will be haha. 

Cableguy Greg

It is heavy. I pulled my cockpit fridge out to change the door swing.

MDboater

jme097 said:

OK guys, my fridge down below in my 280 worked fine last year both shore power and 12VDC. I have noticed this year it will only work when connected to shore power and not on 12V but my cockpit fridge stills runs on both just fine. Is there a module or controller of some sort on the fridge that allows it to run on 12VDC? I am just curious as to where I should start my troubleshooting.  Thanks fellas

Could be a blessing in disguise.  The prior owner of my boat put in a converter so that the cabin fridge runs only when connected to shore power.  I suspect this was the result of several dead batteries from running the fridge while away from the dock.  I have considered changing it back.  In the meantime I keep the freezer filled with cold packs which helps keep things cool after unplugging.  The only minor annoyance is the small amount of freezer ice melt that leaves a puddle in the fridge.

Wildboating

Hmm.  I thought these fridges were always 12vdc, it just pulls from the 110v input when it is energized and pulls from the direct 12v when it is not.  I do believe they have battery protection circuits as well that cuts out the dc connections once it reaches about 10.5volts.   Here is a repair manual i have used in the past.  Maybe it will help you out.

MDboater

Wildboating said:

Hmm.  I thought these fridges were always 12vdc, it just pulls from the 110v input when it is energized and pulls from the direct 12v when it is not.  I do believe they have battery protection circuits as well that cuts out the dc connections once it reaches about 10.5volts.   Here is a repair manual i have used in the past.  Maybe it will help you out.

That's consistent with my understanding.   A converter was added to my boat so the fridge only gets 12V when connected to shore power.  The converter plugs into a 120V outlet (same circiit as microwave) and supplies 12V to fridge. 

Wildboating

Your fridge should have on the back of it a 110v household plug plus another low voltage dc line connected to it.  When the 110v input is energized there is a converter on the fridge that converts the 110v alternating current to 12v direct current.  Why boats do you guys have?  

MarkB

Yea there's a control board. Fridge works on 12V and converts 110V when it sees it. So if the fridge works on 110V it means there's an issue with your 12V power supply.

duane.mosley

the fridge in my 250ec seems to not work as well when on 12v. i have all new batteries, works great on 110v but not 12v

Liberty44140

Agree with Duane. When the 110v is disconnected my fridges switch to 12v but I feel that they are less efficient, less powerful. No data to back that up, just my feeling. 

raybo3

Its not really the fridge that switches voltage it the inverter that switches. The compressor voltage remains the same. You should not see any difference in the cooling weather on battery or 120vac.

duane.mosley

so if it works on 110v, that means the inverter is working to convert 110 to 12v, but not recognizing the 12v when the 110 is turned off ? guess i will pull the fridge and start doing some testing.

Cableguy Greg

@jme097, I had my boat tied to a wharf for 24 hours yesterday. My galley fridge didn't work on 12v. Grr... The lights inside the fridge work, but it isn't cooling on 12VDC. On AC it works great. Did you find anything out?

Cableguy Greg

I found the manual.

http://www.dometic.com/QBankFiles3/EPiServer/Dometic/US/Manuals/Marine-manuals/Refrigeration/CR-Refrigerators-Freezers-Manual_5525.pdf

The part number looks to be 101N0500. Not a cheap little part. There also is a light sequence to see what it going on.

jme097

Wow speak of the devil haha. Sorry that this has happened to you as well! $299???!!!!  Looks like there are 4 different versions of that controller. I am going to order one just so I have it and then once I take the fridge out I will see if its needed. 

Cableguy Greg

My cockpit fridge is working fine, so I might switch the two. Then again, that seems like a lot of work...

Cableguy Greg

@jme097 , if you remove the 4 screws holding the stove down, you gain access to the top of the fridge where the control module is at.

I just found out that my galley fridge is a WAECO CR-0065. This model has a control module number 101N0220. That module has an external AC/DC module which is a Mobitronic MPS-35 switching power supply.

jme097

Oh nice haha. I will definitely be checking things out. I need to get to the bottom of this ASAP! Thanks for the info @Cableguy Greg !