Fridge on DC (battery power)

[BBQ]

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that's a nice arrangement.

[Bud]

Originally Posted by BBQ

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that's a nice arrangement.

Agree bbq, and I'm lazy, so I just ordered one.

Bud

[Bud]

Originally Posted by Bud

Agree bbq, and I'm lazy, so I just ordered one.

Bud

Thanks Mr. markopolo.

The switch is installed and working fine.

Bud

[markopolo]

They're useful units. I have a second one in the house basement used for battery backup on a sump pump.

[JohnnyFry]

Don't overthink the exact resistance value for a couple of reasons: first, most inexpensive meters are not terribly accurate at low resistance values because of resistance in the probe wires and the possibility of a poor connection on what you are measuring. Secondly, there is some variation in the resistance of the element because of measurement temperature and manufacturing variations. If it shows open or something like, say, 10 ohms it is probably bad.

[jmai]

Follow-up

I recently returned from a three week trip to Canada. The refrigerator did what it is supposed to do. We didn't have any spoiled food and even made ice cubes.

Some observations in no particular order.

We used all three modes, AC, DC and propane. AC when in campgrounds with shore power, Propane when in campgrounds without shore power and when driving, Occasional DC use when driving, but it definitely raised the temperature. (I think it works, but not very efficiently).

I have a 2 wireless thermometers with a central receiver so I can monitor freezer and refrigerator temperatures. Definitely worthwhile because you absolutely know what the temps are and how much cooling capacity each mode is capable of generating.

I used one of the battery operated fans inside the refrigerator, blue cube-shaped fan that works on 2 D cell batteries. It ran continuously for three weeks and still did not drain the batteries. Impressive!

Temps varied-from -4 to 20 in freezer and 32 to 54 in refrigerator. Overnight with AC cooled very well.

Use basic principles to keep refrigerator cold.

Leave room for the air to circulate. Blue cube fan helps.

Try to put cold food in refrigerator when on the road-cold beer, frozen items etc. Large, room temperature items will noticeably warm up the refrigerator.

Minimize opening the door-think of what you need and get them all out at once.

When driving and running on propane, sometimes the flame would go out. Monitor the gauge and temperature.

Shut off propane when re-fueling and then drive away from pump before turning on propane valve and re-igniting the refrigerator.

Temperature setting is not easy to turn up and down. Probably better to leave it on one setting. I increased the temperature several times and froze the lettuce!

I used 4 blue ice packs (two small and two large) to help the refrigerator during the day when we were not connected to AC. I froze then at night and then put them in the refrigerator during the day. This worked pretty well to stabilize the temperature.

Check the tray under the freezer that catches the melted water from the freezer fins. During our trip, it was minimal, but there was some water to empty.

I use the expanding, spring-loaded bars to keep items on the shelves. Very simple and effective.

After the trip, clean out and wipe all surfaces of the fridge and air it out.

My latch has two positions, one to keep the door fully closed and one that keeps it open about 1/4 inch for airing out. (I use this position when we are not traveling and I also prop open the freezer door. Good air circulation when not is use is the key).

Make sure your gaskets are sealing properly and have no gaps.

After you load the fridge, make sure no items are keeping the door open. I noticed it was possible to close the latch and have gaps between the gasket and the front edge. I usually pushed in the expandable bars a bit or re-arranged items in the door.

When parking, try to keep the refrigerator side in the shade. This works and make a difference.

During the day when we start and stop and go in and out of the RV, the refrigerator knob needs to be adjusted for DC or propane. Its easy to forget and not have the refrigerator on. Make it part of the checklist items and check the temperature monitors.

The ammonia based refrigerators definitely need to be level to work. This is fairly easy to achieve when you are in a campground with leveling blocks. However, when you park and leave the unit for a hike or to go to see some sights, you may be on uneven ground. If it is really tilted, it is probably better to turn it off while you are gone. (This is where the blue ice packs are really helpful). The previous owner put bubble levels that I can see from the driver's seat. One over the rear view mirror for side to side leveling and one over the top of the passenger's door for front to back leveling. Simple, yet effective.

Get to know your refrigerator and how it works and how efficient it is when you are home. Try it out in the driveway for a few days. (My wireless monitor works from driveway to my house so I can see how it is cooling). The last thing you want is a surprise when you are out on a trip and notice the temperature won't go below 50 degrees.

Realize that these ammonia based refrigerators are basic. Be realistic. These are not units that you simply turn on and forget for a week. They need monitoring and leveling.

So, it is possible to use your refrigerator on all its modes in both campgrounds and boon- docking situations. Just be realistic and don't expect it to be like your home refrigerator. When we got home I was able to empty the refrigerator and use all the food we didn't use, especially the condiments. My test was the mayonnaise, still good after three weeks!

[Porsche911]

Interesting, I have been informed never to drive and use propane, am I missing something here?

[wincrasher]

Part of your problem may be over-stuffing the refrigerator. A 3-way fridge needs air movement inside to work. You can't pack them in like your compressor fridge at home. Many people put battery operated circulation fans inside to help even out the cooling and making them work more efficiently.

FWIW, it's perfectly fine to drive with the refrigerator on LP. Only in certain tunnels are you required to turn your propane off.

[jmai]

Originally Posted by Porsche911

Interesting, I have been informed never to drive and use propane, am I missing something here?

Some people do and some people don't. I've read comments both pro and con.

If my DC mode worked better, I wouldn't use propane when driving.

[Bud]

"32 to 54 in refrigerator"

Hi Joe,

My experience was not much different than yours, Until I used fans outside the refer, less than 50 driving 70mph and 95 degrees. Many others experience the same with Roadtreks like mine 05/04 190P. Some manufacturers do a good job with the air Outside the refer and some don't, like mine. Some even install fans outside the refer.

Bud

[Bud]

Originally Posted by markopolo

The power consumption specs for my 20+ year old - manual control - Dometic RM2410 are listed as:

DC Heating Element: 125W
AC Heating Element: 160W

I don't think the DC wire has ever been connected. It is still neatly coiled up as if new. I guess the previous owner either didn't run it while driving or used it in gas mode.

Like Bud, I run it on AC while driving using an inverter. My setup has an added $50 (when I bought it 5 years ago) Xantrex Pro-watt automatic transfer switch so no plugging/unplugging needed.

It is easy to turn the fridge off by turning the inverter off as the inverter switch is easily reachable from the drivers seat.

An Update and Warning markopolo,

After your post above, you may recall that I purchased and installed the automatic transfer switch. Thanks again, really like it.

Concerning the Warning above, you're more at risk than me? I'm using 2 Walmart marine batteries, inexpensive unlike your fine setup.

I can't explain exactly what happen, but I did get lucky just by accident. I stopped for the night in a private campground about a month ago. They had just opened 3 new camping spots far apart with no one else there. It appeared I was the first from the beautiful grass and more.

I one quarter wake up hot, sit up in bed and turn on the a/c. Not sure if the compressor tried to start or not, maybe just the 12 volt noise from the thermostat and ac unit. It does not start *!#!! along with some choice word for the situation. Oh well, it is not hot out, I'll just use the fastastic fan. No, I should go outside and plug the portable surge protector out and in. The lights were on the unit, but heck if I could recall what they meant. Back inside and the ac still won't work, just the 12 volt sounds. Oh well, I'll just turn on the fan and go back to bed. I'll figure it out the morning. I got lucky, I noticed the battery meter even though I was not looking for it. It showed 12.1 volts.

I was still half asleep and almost did not react. Then it was huh? How could the batteries not be fully charged? Then it was obvious, there was no 110 volts for the battery charger, no shore power. The refer was running off 12 volt inverter power, Just like it was suppose to! I was not concerned at this point as there was still plenty of battery left, volts popped right up after turning off the inverter. Oh well, I head back out and try again. No wait, I turn off the battery disconnect switch first. I sure like my flashlight.

After that all was well, ac etc. What happened, heck if I know. I do know I would have been heading to a Walmart for 2 new batteries if I had not woke up, etc.

May shore power always be with you markopolo.

Bud

[markopolo]

Interesting story.

I wonder if it was a temporary problem with the 30A transfer switch?

It's a good idea to check the battery meter after plugging in to confirm battery charging.

[Bud]

Forgot to mention that I definitely had shore power and batteries charging at some point prior to bed. I could have lost shore power anytime after the last time the ac shut off.

I don't know for sure, but I think that the ac compressor turned on momentarily when I tried to turn the ac on.

Your guess may be right, or maybe the surge protector saw something it did not like when I turned on the ac. And still did not like it when I plugged the the surge protector out and in. Then all righted itself when I shut it all off with the battery disconnect switch, and then unplugged the surge protector. When plugged back in, all was normal.

Just don't loose shore power when asleep, or shopping, or.................... No big risk for me without 800 amps of agm batteries.

Bud

[Eraygunz]

Hi.
I have had this same issue.
On 12 volts ,my unit dose not do very well.
But on 110 it works just fine.
So I added an inverter,and run it on 110 all the time.
Takes a good 36 hours or so. To get it really good and cold.
I too added a small fan inside,which seems to help a lot .
I was thinking of trading out the fridge........but.
The 12 volt ones that I found usually do not have a freezer.
And it seems that most kitchen appliances today are not built to last.
So for now I will use the old original. And replace it with a compressor type when she stops working.

[MsNomer]

I also keep a wireless remote thermometer in the fridge. My Engel 12V/AC fridge can do this with minimal power usage:



Don't know how much more it can do, but I suspect it could get to 0°. The rheostat was set to its lowest (least cool) setting--I've never tried the other four levels.

[Phoebe3]

Originally Posted by MsNomer

I also keep a wireless remote thermometer in the fridge. My Engel 12V/AC fridge can do this with minimal power usage:



Don't know how much more it can do, but I suspect it could get to 0°. The rheostat was set to its lowest (least cool) setting--I've never tried the other four levels.

I looked at Amazon for wireless remote thermometers. Do you have your readout mounted on the dash? Was wondering how far the sensor would transmit. Our refrigerator is about 10 ft from the dash and on the other side of the bathroom so there would be several "walls" to go through.

[MsNomer]

I don't think you will have a problem. It will hold signal even if I take the remote outside.