Questions on Refrigerator Operation

[msalazar51]

We have just returned from three weeks on the road with our Rockwood Freedom 1910. We had a great time but we could not keep our fridge running on the road? Our gas would not remain lit and we tried once to shut off the gas and turn on the 12v while towing, still not working. Suggestions?

[Bama Rambler]

The wind from moving down the highway was probably blowing the flame out. You could try to add a small deflector to the bottom vent to direct the wind around the grate and not into it. It won't take much.

As for the 12 volt operation. How did you try to get it to operate?

[raspivey]

We had a 2012 2280BH...identical refrigerator. Give up trying to run propane on the road, we never could make ours stay lit. On battery, you probably won't be able to tell it's running. At best, 12V will maintain temp...usually won't quite do that. It'll cool, just not well. That's assuming your battery's good and no fuses are blown.

[rockfordroo]

Originally Posted by raspivey

We had a 2012 2280BH...identical refrigerator. Give up trying to run propane on the road, we never could make ours stay lit. On battery, you probably won't be able to tell it's running. At best, 12V will maintain temp...usually won't quite do that. It'll cool, just not well. That's assuming your battery's good and no fuses are blown.

On my Coleman, I installed 2 LED's on the +12VDC to the fridge. I put a green one on ahead of the thermostat and a red one on after the thermostat. So the green one told me I had power from the TV and the red one told me the fridge was calling for power.

I drilled a couple holes in the outside fridge panel and mounted them there so I could see what was going on with the camper folded down.

See attached.

[msalazar51]

Originally Posted by Bama Rambler

The wind from moving down the highway was probably blowing the flame out. You could try to add a small deflector to the bottom vent to direct the wind around the grate and not into it. It won't take much.

As for the 12 volt operation. How did you try to get it to operate?

Just switched it on (red switch) in the "control box?"

[msalazar51]

Originally Posted by rockfordroo

On my Coleman, I installed 2 LED's on the +12VDC to the fridge. I put a green one on ahead of the thermostat and a red one on after the thermostat. So the green one told me I had power from the TV and the red one told me the fridge was calling for power.

I drilled a couple holes in the outside fridge panel and mounted them there so I could see what was going on with the camper folded down.

See attached.

Not sure I understand, in spite of the simplicity of the schematic, the green LED means that the tow vehicle is supplying the power and the red means that the fridge is drawing on the deep cycle alone?

Not completely sure I get the whole three way power thing. Green and red switches off, pilot lit then propane is my source. Pilot out, green switch on, red switch off, I am on 110v (plugged into 30 amp). Pilot out, green switch off, red switch on, I am on the 12v deep cycle battery alone, the worst way to run the fridge?

I get that if I am plugged through the pigtail to the tow vehicle then the 12v deep cycle is receiving a trickle charge. So, if I am plugged into the tow vehicle and have the 12v on, then the fridge is being powered by the deep cycle while the deep cycle is receiving a trickle charge, is that right?

If the last part is true, and I run the 12v to power the fridge while driving won't I eventually kill my deep cycle battery?

Thanks for any advice.

[raspivey]

Originally Posted by msalazar51

Not sure I understand, in spite of the simplicity of the schematic, the green LED means that the tow vehicle is supplying the power and the red means that the fridge is drawing on the deep cycle alone?

Not completely sure I get the whole three way power thing. Green and red switches off, pilot lit then propane is my source. Pilot out, green switch on, red switch off, I am on 110v (plugged into 30 amp). Pilot out, green switch off, red switch on, I am on the 12v deep cycle battery alone, the worst way to run the fridge?

I get that if I am plugged through the pigtail to the tow vehicle then the 12v deep cycle is receiving a trickle charge. So, if I am plugged into the tow vehicle and have the 12v on, then the fridge is being powered by the deep cycle while the deep cycle is receiving a trickle charge, is that right?

If the last part is true, and I run the 12v to power the fridge while driving won't I eventually kill my deep cycle battery?

Thanks for any advice.

I believe you've got it down. I always ran double batteries and shorter trips, so I never killed a batter. It's highly likely the TV won't keep up and you'll eventually kill a battery. I'd say three or four hours with a single 12V should be ok though provided you don't need to rely on the battery when you get where you're going.

What I meant by not being able to tell it's running was that it just doesn't cool as well as the other power sources.

[rockfordroo]

Originally Posted by msalazar51

Not sure I understand, in spite of the simplicity of the schematic, the green LED means that the tow vehicle is supplying the power and the red means that the fridge is drawing on the deep cycle alone?

Not completely sure I get the whole three way power thing. Green and red switches off, pilot lit then propane is my source. Pilot out, green switch on, red switch off, I am on 110v (plugged into 30 amp). Pilot out, green switch off, red switch on, I am on the 12v deep cycle battery alone, the worst way to run the fridge?

I get that if I am plugged through the pigtail to the tow vehicle then the 12v deep cycle is receiving a trickle charge. So, if I am plugged into the tow vehicle and have the 12v on, then the fridge is being powered by the deep cycle while the deep cycle is receiving a trickle charge, is that right?

If the last part is true, and I run the 12v to power the fridge while driving won't I eventually kill my deep cycle battery?

Thanks for any advice.

Yes, the green LED means there's 12VDC being supplied to "the fridge." The red LED means that the thermostat has seen the inside temp is rising and has turned on the heating element to cool the fridge back down. (In case you aren't aware, these RV fridges run on an ammonia cycle where the gas/electric actually heats the ammonia, which ultimately cools the fridge. Sounds counter-intuitive, but it works.)

I can't speak for your fridge regarding it's controls. My Coleman's fridge (circa 1987) wasn't really a 3-way. It was 2-way: gas and 12VDC. The 12VDC came from the converter if you had shore power and from the TV when going down the road (I didn't have a battery). I'm guessing my fridge 30 yrs ago was a lot smaller than what they're putting in popups today, but I never had an issue with the TV not being able to supply enough current for the fridge's heating element. (The bigger the fridge, the more power needed to cool it, hence a larger heater pulling more current would be required.) But in my case, I don't think having a battery would have changed anything.

With respect to the TV supplying the battery/fridge, they will both look like loads (i.e., the TV will supply them both) provided the TV is supplying at least a much current as the fridge is asking for. But the battery can be both a load and supply, so if the fridge wants more current than the TV can supply, then both the TV and battery will supply it. In this case, you will actually be discharging your battery.

Usually the TV power is protected by a 30 amp fuse under the hood. That would make you think the TV should be able to supply almost 30 amps. The problem is that the wire they use from the fuse block back to the plug at the hitch is usually fairly thin. A thin wire doesn't allow much current flow. If you suspect you're discharging your battery while running the fridge on the road, you could run a larger gauge wire from the fuse block to the hitch plug.

If you post the make and model of your fridge, you may get more, better, specific answers to your problem.

[pgandw]

Originally Posted by msalazar51

Not completely sure I get the whole three way power thing. Green and red switches off, pilot lit then propane is my source. Pilot out, green switch on, red switch off, I am on 110v (plugged into 30 amp). Pilot out, green switch off, red switch on, I am on the 12v deep cycle battery alone, the worst way to run the fridge?

I get that if I am plugged through the pigtail to the tow vehicle then the 12v deep cycle is receiving a trickle charge. So, if I am plugged into the tow vehicle and have the 12v on, then the fridge is being powered by the deep cycle while the deep cycle is receiving a trickle charge, is that right?

If the last part is true, and I run the 12v to power the fridge while driving won't I eventually kill my deep cycle battery?

Thanks for any advice.

I have been researching how to best operate the fridge for the whole time I have owned my 2014 A-frame.

The fridge installed is a Dometic 4223. From the beginning, it has cooled very inconsistently. Some trips would be great, some there would be no cooling at all.

So I did some research and experimentation.

1) I downloaded the Dometic manual and installation instructions. I found out this particular fridge has a 160 watt heating element on both AC and DC. This means the fridge draws 13 amps on DC. Unless you have the same model, your fridge is likely different.

2) We often drive 8-10 hours to get to a campsite on the first day of a trip. The fridge will not stay lit on propane while driving down the road. However, that same wind makes it cool pretty effectively on DC - MOST of the time. On hot 90+ degree sunny days, the fridge warms up pretty quick when we make a pit stop or sign in to a campground. The lack of airflow when stopped means the fridge doesn't cool enough to prevent warming up. And it's still eating 13 amps but no recharging is going on.

3) I needed a battery-powered wireless thermometer ($10 at Walmart) to keep track of what the fridge is/was doing. I put the sensor inside the fridge, and the receiver/indicator in the minivan when towing. I put the receiver on the counter inside the A-frame when camping. With a glance I can tell what temp the fridge is at. I am still using the original set of AA and AAA batteries after 2 years.

4) I had to add a computer case fan (120mm) ($12 at Best Buy) on the fridge exhaust vent to get the hot air out, and the cool air in. Normally, I don't run the fan when towing. But this week towing in 95 degree bright sunshine, any stop or slowdown was enough to reduce the airflow and the fridge temp to rise into the 40s. Not good enough - I need to run the fan while towing on really hot days.

5) I also installed a digital voltmeter to have an idea of how my 2 golf cart batteries are doing. If I don't have an hour long check-in at the campground, my batteries are usually at 12.5V (12.7 is full) when we start to camp. The wiring from the minivan to the camper has a little too much voltage drop when the fridge is on DC and using 13 amps for the minivan to keep the camper batteries fully charged. If I have the fridge turned off for the last couple of hours of driving, the batteries are fully charged upon arrival. I have changed all my lights to LED, including marker and tail lights, to reduce the added voltage drop when my lights are on.

With the computer case fan running while camping (takes 0.07 amps), I can set the fridge down around "4", and it will maintain below 40 degrees on either propane or AC on even the hottest days. When days are below 50 degrees, I have to turn the fan off to avoid the fridge freezing at the lowest settings.

just things I have learned the hard way
Fred W
2014 Rockwood A122 A-frame pop-up
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[GlennW]

I had similar issues on my Rockwood 1640 Ltd with the Dometic RM 2193 not staying lit on propane. ran a 110V extension cord from the back of my SUV to the fridge compartment and plugged the fridge AC cord into that. A small gauge extension will do as the fridge only draws 200 watts or so.

Inside the SUV I had a 400 watt 12-110V inverter (cheap modified sine wave) and plugged into that. My SUV had a rear cigarette lighter socket. Fridge always stayed at temperature in transit. Note that on some Dometic fridges, only the 110V element is controlled by the thermostat. The 12V input would need a large gauge wire from the TV battery to work well.

Just be sure that the lighter socket turns off when the vehicle isn't running for those long stops. The fridge will stay cool for an hour or so.

This worked well for many years. Always arrived with a cold fridge.

Glenn

[Fiddler Dan]

A small spider web or dust can cause the problem. Blow the orifice out with a compressor or canned air when it is not lit.