Refrigerator compressor does not work on 12v DC power, but works on AC power

[birdgs]

Hello,

I have a replacement Norcold DE 105 refrigerator in my 2021 Entegra Ethos. The first refrigerator stopped working on the very first day. It is supposed to run on AC or DC power, and is not powered by propane.

a. It runs fine on AC power but the compressor will not run on DC power.

When plugged into shore power, the refrigerator works

When driving, the refrigerator works

On generator power, the refrigerator works

b. The compressor will not run on DC power

The light comes on and the fan comes on, but the compressor tries to start and turns off

DC voltage at the plug going into the refrigerator is 12.4 volts (measured with a volt meter). The refrigerator isn’t supposed to stop running until it falls to 10.4 volts.

The AC outlet the refrigerator is plugged into is not powered on when using the inverter. I’m not sure this is a problem, but it means that I can’t use the inverter to power the refrigerator.

All fuses look good, including the 15amp inline fuse on the DC power input line.

I’ve charged the two 105Ah AGM batteries using both solar and shore power. I charged with shore power for 36 hours straight before my last tests.

Do you have any suggestions on troubleshooting?

Thank you!

[SteveJ]

Is the voltage measurement that you took with the compressor trying to start? If not, take a reading when trying to start the compressor on DC.

[JohnnyFry]

My guess is that the wiring from the DC Panel to the fridge is too small a AWG and you are getting voltage drop when you try a start up. Put a Voltmeter on the terminal block on the fridge and not what happend when you try to start up. I suspect that you drop below the 10.4 volt threshold on compressor startup and the compressor will not start. When you are driving the voltage will be higher with the alternator running but when you are stopped you come under the threshold. The cure is to run large gauge wireing from the DC panel and make sure that you have a solid ground to the vehicle chassis.

[birdgs]

Thank you for your help. After hours of troubleshooting over many days, your comments made me think that the one place I had not tested was the 7 or 8 wire connections to the back of the refrigerator. After taking a picture of the wiring, I removed every connection and tested with my volt meter. The voltage entering the refrigerator as it was turned off was 12.45V. I reconnected each wire where they were, and it did not turn on. So I pressed all connections in firmly and heard a click, like one of the connections was not firmly seated even though all looked connected. Now, the refrigerator has been running 90 minutes off of DC power with no issues at all. The only thing not happening now is the LED isn't coming on. Tomorrow, I'll reseat all connections again and am sure it will come on. Thank you very much!

[rowiebowie]

Originally Posted by birdgs

Thank you for your help. After hours of troubleshooting over many days, your comments made me think that the one place I had not tested was the 7 or 8 wire connections to the back of the refrigerator. After taking a picture of the wiring, I removed every connection and tested with my volt meter. The voltage entering the refrigerator as it was turned off was 12.45V. I reconnected each wire where they were, and it did not turn on. So I pressed all connections in firmly and heard a click, like one of the connections was not firmly seated even though all looked connected. Now, the refrigerator has been running 90 minutes off of DC power with no issues at all. The only thing not happening now is the LED isn't coming on. Tomorrow, I'll reseat all connections again and am sure it will come on. Thank you very much!

Thanks for posting your resolution. Not everyone who posts about a problem does that and instead leaves us hanging.