Dometic AC/DC Refrigerator issue

[sailscubasurf]

I recently purchased a Dometic CF-110 ac/dc refrigerator / freezer and have been having a periodic issue with it while using it on 12 volt dc.

The refrigerator is supported by a 360 amp battery bank, which is charged by 400 watts of solar panels. After a hot night, I have only used 2% of the battery banks capacity. However, when I check the frig/freezer in the morning, the blinking error light is on and the temperature has risen in both boxes.

One person, who seemed to be knowledgeable, said it was because the Dometic 's are very sensitive to voltage drop and said to increase the size of the wire to the 12 volt outlet.

Does this seem correct? Conversely, since I have more than enough capacity, would it be better (though less efficient) to install and inverter and run the unit off of A/C all the time?

Any experienced electricians or others have any advice? It would be greatly appreciated.

[DeepFrz]

What size wire are you using now and how long is the wire run? That will give us some idea on whether increasing the wire size will help or not. The DC wire should run on its own circuit from the battery bank, through a fuse and then directly to the frig. The use of a 12volt outlet is worrisome.

[Zil]

Those compressor fridges have 12 volt DC motors. Running on 120V AC is not advised. My Idel-B is 25 wire feet away from my battery. I have 10AWG pos & neg wire that is wired direct to the Indel-B. I replaced the plug with ring terminals and fasten to buss bars. It works fine. You have a bad ground, a light wire, a poor connection, or some combination. Granted mine uses less amps that a larger unit, but it is all relative.

[john61ct]

Originally Posted by sailscubasurf

After a hot night, I have only used 2% of the battery banks capacity.

What exactly gives you that impression?

[Bleemus]

Originally Posted by john61ct

What exactly gives you that impression?

I was wondering the same thing. Seems almost impossible running a fridge with such a small bank.

[john61ct]

Well, if the fridge was actually not working, just the blinky lights running.

Butmy point was even expensive battery monitors aren't that accurate.

[sailscubasurf]

The refrigerator / freezer uses 6 amps when it's running, and runs about 20 minutes an hour.

My solar panels top up the batteries by 11am on even a partly sunny day.

[captain mitch]

The 360ah batt. bank seems to small for running a fridge at night.
I have both a Dometic 12/110 fridge and a 12v freezer running on board and sipping off a bank of 8 trojan 105s.
And , Yes, they are very sensitive to voltage drops, so , at the very least I would run a direct connection (with fuse or breaker) from the batteries to the fridge and see if it will get by. If not , add another battery to the mix to keep the voltage up at night.

[ayates]

To be on the safe side, I wired a new Novakool RFU-9000 with #6 cable for the 12V connection.


Allan.

[foufou]

6 amps should not require #10 wire. Connections are a more likely suspect. Have you checked the voltage at the fridge?

[DeepFrz]

The fact that the frig. uses 6 amps while it is running has nothing to do with the problem at hand. They are very sensitive to momentary (read milliseconds) voltage drops that you will not read with an ordinary VOM. These occur when the compressor starts up. Running your frig through a 12 volt connector is folly.

[john61ct]

Originally Posted by DeepFrz

Running your frig through a 12 volt connector is folly.

If you mean ciggie port style, I 100% agree, unreliable and can be dangerous even at low amps, avoid like the plague.

But there are dozens of quick-release connector styles designed for 12V that are physically secure and safe at even hundreds of amps.

Andersons the prime example.

[john61ct]

Originally Posted by captain mitch

The 360ah batt. bank seems to small for running a fridge at night.

Not if a good quality true deep cycle bank.

Of course, the available charge inputs need to be there to replace power used each day.

And efficient compressor systems help.

Bigger banks give more charge timing flexibility, and greater longevity.

[SecondBase]

If you have an inverter can you try to switch over to inverter-110v during the outage -- if that setup cools it is most likely not a battery, battery monitor, or even fridge unit issue.

[cottonsail]

We use an inverter all the time underway. 6 deep cycle group 27's and a 500 watt solar system with an MTTP Outback controller gives us plenty of 110 electric.