Your refrigerator is running all the time but nothing is really cold. Is it time to call in the refrigerator repairman? Or is it something else?

Refrigeration Problem? Or Bad Batteries?

You reach in the refrigerator for a cold drink and think that the cans don’t feel as cold as usual.  You write it off to just not remembering when you put them in, or the fact that it’s a really hot day, or that you put a lot of warm stuff in the refrigerator . . . whatever.

But a little later when you go to get something else out, you can’t deny the fact:  it’s not as cold in there as it should be.  Maybe the frost on the chill plate is melting.  Maybe things in the freezer are thawing.  Uh-oh. [I know, I know . . . if you don’t have refrigeration, you don’t have these problems.]

And your first thought is that it’s a problem with the refrigerator.  [Well, duh . . . the refrigerator is not keeping cold so it’s OBVIOUSLY a problem with the refrigerator!]

So you start by pulling out the owner’s manual, any repair books you have or maybe you proceed straight to the big guns and call the refrigerator technician.

All of the above happened to us.  The refrigerator had been working just fine and the weather hadn’t suddenly turned hot, nor was there any obvious explanation for the problem.  So we assumed that the refrigerator needed to be recharged.  We read up on the procedure, borrowed gauges and proceeded to do it.  No improvement.

We then decided that the problem was beyond us and called in the refrigerator repairman.  He figured that we had added too much refrigerant, so evacuated it all and then recharged it, leaving us with instructions on how to let out a tiny bit more gas if it still wasn’t cooling right. And he told us to allow 24 to 48 hours for everything to “settle out.”

Two days later, it was obvious that refrigeration was worse, not better.  And now the refrigerator was running literally all the time, and eating up every bit of power we had.  Normally, our solar panels could keep up with our power needs but now they weren’t.  We were having to run the engine for a couple of hours a day — yikes!

And so we just turned the refrigerator off, except when we were actually testing something on it.  Drinks went in a cooler (luckily we were anchored in a town and could get ice) and we otherwise did without refrigeration.

That’s when we had the big revelation:  even without the refrigerator on, our batteries were drained overnight. While the solar panels were putting power into the batteries, the batteries weren’t holding the charge and thus the voltage was down most of the day (mid-day the voltage was up when the sun was at its peak with the solar panels).

So how did this affect the refrigerator?  With low voltage, the compressor didn’t operate efficiently and thus the box didn’t cool as well.  The thermostat kept saying that the box wasn’t cool, and told the compressor to run longer.  The compressor running longer took more battery power, dropping the voltage still further.  And the circle continued ever downward . . .

Three days later, we had new batteries (I’ll spare the details of the fun we had other than to say that Dave used almost all his “sailor who worked in a steel mill” words as we got the old ones out and the new ones in to a very inaccessible compartment and hooked them all up) and a few hours later we had a COLD BEER from the refrigerator!

Moral of the story:  If your refrigerator isn’t as cold as it was, and is running more and more with no apparent cause such as suddenly hotter weather, it might not be a problem with the refrigerator but with your batteries.

After the fact, we discovered that the “troubleshooting panel” on the refrigerator compressor did have a light for low voltage, but we missed seeing it because of the way that the unit was mounted.  We later helped some other cruisers figure out similar problems by knowing to look for this.  One note, though:  to check for low voltage, all charging sources (solar, wind, alternator or generator) have to be off, typically for a half hour or longer.

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  • Tami
    Posted at 26 June 2013 Reply

    There is a saying amongst mechanics: “start simple and move to the complex.”

  • Kim Veitch Davidson on Facebook
    Posted at 26 June 2013 Reply

    Thank you. We are having this problem now.

  • The Boat Galley on Facebook
    Posted at 26 June 2013 Reply

    Oh, so sorry to hear that Kim. Hope you get it sorted out!

  • Jim and Barbara Shell
    Posted at 26 June 2013 Reply

    Knowing the temperature inside the box is a critical part of evaluating whether the refrigeration is working. We tried several refrigerator thermometers but had to open the box to read them. We now use a battery powered remote inside/outside thermometer that displays the inside temperature all the time. We place the display unit in an easily seen location. The internal unit can be moved around to suit your needs. The units are available at Radio Shack and other stores. It is a real comfort knowing what is the inside temperature. In 2006 while out cruising, we noticed a rising temperature and were able to replace the blown fuse before any thawing occured.

  • Mike Wilson
    Posted at 23 June 2014 Reply

    The modules on Danfoss compressors are very sensitive to low OR fluctuating voltage and will cut the system out and then try and restart it. After many short cycles this can result in blowing the $300.00 module. Most vessels wire the refrigeration through a breaker on the main DC panel. This is a No No and is stated by Danfoss themselves. It is better to wire the system directly to the batteries with a suitably sized breaker or fuse AT the batteries to comply with A.B.Y.C. guidelines

    MexiColder Mike

    Marine Refrigeration Engineer (Dip. Mech./Mar. Eng. U.K:)

    AKA Rescue Refrigeration Mazatlan Sinaloa Mexico

  • Patrick Hunt
    Posted at 19 July 2016 Reply

    Excellent Advice -as USUAL! Great website. I’m going to get an indoor outdoor thermometer.

  • Tobi Horn
    Posted at 21 April 2017 Reply

    Great article (as always from your page).

    One easy hint which leads to the battery rather than to the fridge when having warm beer out of the fridge is, when motoring for an hour or so (no wind or looking for an anchoring spot): the beer IS very cold afterwards. That means that the fridge does work properly, but needs power to do so. Which a dying battery and/or insufficient charging cannot provide.

    On another note regarding the fridge:
    Does your fridge ligth goes out when you close the door? Or is it still on and consuming (little, but) unnecessary battery juice when closed?
    My brand new Benneteau did exactly this and the only way to find out is putting a camera / mobile phone in the fridge – camera still on video – when closing the door.
    Easy fix afterwards whit installing a seperate switch on the outside to turn on / off the ligth.

    Second sigth note regarding fridge efficiency :
    consider installing a small little ventilator (e.g. computer cooling fan) inside the fridge to move the air inside: it’s a BIG increase in cooling for less than 1 US Dollar material and 2 to 3 hours of work.

    fair wind,


  • Ron Harbin
    Posted at 12 May 2017 Reply

    Thanks Carolyn. About 3 years ago, I did some similar troubleshooting when my portable Norcold fridge wasn’t working “properly”. I’d hear the compressor come on during the night and it would cut off after about 5 seconds. A few minutes later, it would try again. I almost took it to the repair shop. Then I realized the voltage at the fridge was below the necessary threshold. When the compressor starts, that is a fairly large load that drops the voltage (temporarily – but long enough to keep it from starting). Now, I just leave the battery switch on “both”. The fridge runs great now. I don’t have a separate engine battery (on my Pearson 31) but I do have a couple backups and watch battery status like a hawk.

  • Peter Shaughnessy
    Posted at 14 May 2017 Reply

    My sister’s boat had the same problem but it was not the fridge or the batteries, Instead it was a poor connection (corrosion) in the power supply to the fridge. Bad connection equals voltage drop, amperage increase, inefficient compressor… and finally warm beer.


  • Jean Strin
    Posted at 04 December 2017 Reply

    We installed a Hobbs meter (hour meter) on our fridge. We could tell by the hours used if we were headed for a problem. We also connected an led to the circuit so we could tell if the fridge was running.

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