Refrigerator not working correctly on DC - Page 2

08-01-2007, 12:13 PM

I will second the point that running the fridge on DC while towing does not deplete the TM battery for everyone. I have no problem. I agree that some vehicles apparently have non-optimum wiring to the hot lead from the TV to the plug.

If my battery is a little low when I leave home, then it will be less low (more charge) when I arrive in camp, even though I have the fridge on DC. Apparently my TV puts out enough power to both operate the TM fridge and also have some power left over to charge the TM battery while towing. Tehre are two primary fators:
1. size of the TV alternator. My mechanic says mine will produce 120 amps.
2. size and condition of the wires for the charge circuit. Some people have had good luck replacing the factory wiring. My factory wiring is working just fine.

**Bill** · 08-01-2007, 12:40 PM

Quote:

Originally Posted by commodor47

Bill,

If I am reading the diagram correctly, there is a 20 A circuit breaker for the AC leg of the refrigerator and a 15 A (blade type) fuse for the DC leg.

Dick -

Yes, you are reading the diagram correctly. But this is the diagram of the power distribution inside the converter, and I think Scott said he has checked all these fuses/breakers.

There are several other fuses that do not show up on this diagram because they are located within the individual appliances. In particular, the refrigerator has a 3-amp fuse in the AC power line, and a 20-amp fuse in the DC power line.

As another example, the toilet has a 5-amp fuse in the flush-button housing.

Bill
--------

Just noticed that this diagram, which is getting pretty long in the tooth, doesn't explicitly show the safety cutoff switch under the edge of the bathroom wall, either. Apparently, that switch is understood to be included in the "Rear roof and LP detector" block on the lower right.

**rickst29** · 08-01-2007, 01:20 PM

slightly OT...

My 2619 (built 2006) contains Norcold model N300.3rh. If I "pre-cool" using 12V while closed, what happens temp-wise?

BTW, although there is a dial for "coldness", it doesn't seem to have any relationship to temperature when running on 120v: I need to turn it up to 4-5 on hot days, and down to about "2" every night in order to keep the temp relatively constant. It seems to function only as a timer-control thingy, not a thermostat-controlled thingy.

Just like the home fridge, I get to choose numbers like "1-2-3-4-5, not numbers like "35 degrees - 38 degrees - 41 degrees - 44 degrees". Were the old ones actually measuring temp inside?
- - - -

Anway, here's the question: Should I disable the "A/C kill" switch on the bathroom door, so that I can cool down using 120v A/C instead of 12v ? (while plugged into shore power).

08-01-2007, 01:41 PM

rickst29 - NO. the "kill Switch" is only DC and is a safety item to prevent a ceiling light from accidently coming on while the unit is closed which could start a fire. It has no effect on the AC power distribution.

Bill

**Bill** · 08-01-2007, 02:34 PM

Quote:

Originally Posted by rickst29

My 2619 (built 2006) contains Norcold model N300.3rh. If I "pre-cool" using 12V while closed, what happens temp-wise?

Without a thermostat, the cooling mechanism continues to run forever, no matter how cold the box gets. Now, none of these 3-way refrigerators has a very potent cooling capabilty, so it takes a long time to get really cold. But eventually, if the temperature inside the TM is moderate, they will freeze everything in the refrigerator compartment. This is what Freedom meant when he said "The trouble with running the frig on 12 volts ..." Please note that "eventually" can mean a day or two.

Quote:

BTW, although there is a dial for "coldness", it doesn't seem to have any relationship to temperature when running on 120v. Were the old ones actually measuring temp inside?

I have had the same experience, though not quite as bad as you describe. I would describe it as "a loose relationship". It will eventually cut off the cooling unit, but the temperature is far from constant over the cycle. Isn't that annoying? And no, the old ones didn't measure temp any better than the new ones - but they did have a thermostat on the DC setting as well as the AC setting.

By the way, one thing that helps this situation a lot is to put one of those little 2-D-cell fans inside the refrig. The temperature does tend to stay quite a bit more even if you induce some air circulation. Camping World has them, as do most RV supply places.

Bill

08-01-2007, 03:27 PM

From my experience, as far as I can tell, the temperature control on the front of the fridge works on AC and on propane. It is not the same, meaning that if I find a setting that I like for AC then if I switch it to propane I may not like that setting.

Some claim that the setting has no effect on DC. I do not know, since I have never measured it.

For the few times that I have been camping with shore power, I have to experiment to find a good setting so that the milks stays cold and the lettuce does not freeze. Mostly I use propane, and have to perform the same experiment.

I try to target 40 degrees. If it hits 45 I set it a little colder. If i drops to 35 I set it a little warmer.

When the outside temperature fluctuation is very large (70-100) then I have to use different settings for daytime and overnight. This is very annoying.

**rickst29** · 08-01-2007, 03:58 PM

#1: So A/C stuff, including stuff plugged into the A/C outlet next to the fridge, should operate fine even if the bathroom wall is down? I'll leave the switch un-modified.

#2: I'll buy one of those little fans

#3: BTW, my temps are measured via the "Outdoor Sensor" of a LaCrosse Technology digital clock. (It also displays time on the ceiling in the dark, a nice feature). There's important and expensive meds in our fridge, I can't afford an error. And, as you anticipated, I am talking about high-desert temp differentials of 40+ degrees difference between day and night.

**commodor47** · 08-01-2007, 04:00 PM

Quote:

Originally Posted by Bill

Dick -

There are several other fuses that do not show up on this diagram because they are located within the individual appliances. In particular, the refrigerator has a 3-amp fuse in the AC power line, and a 20-amp fuse in the DC power line.

Bill,

I checked the refrigerator manual and it does reference two inline fuses: one 3 A and one 20 A. I had our unit closed up until a short while ago. Just opened it and removed the outside lower access grill to the refrigerator. Sure enough, tucked in the lower left hand corner is the terminal block with two inline fuses (in black fuse holders, tube type). Both are clearly labeled with a white tag.

Always a learning experience . . . and a valuable one regarding the refrigerator.

**Bill** · 08-01-2007, 04:00 PM

Quote:

So A/C stuff, including stuff plugged into the A/C outlet next to the fridge ...

Rick -

I hate to nit-pick, but for future reference, the abbreviation "A/C" usually refers to "air conditioner", while "AC" to refer to shore power. Makes the posts a lot easier to read. I'm busily trying to figure out what the "air conditioner outlet next to the fridge" is.

Thanks

Bill