Dorm fridge amp draw

gregtx · 02-27-2017, 06:05 PM

Plan on doing a little dry camping this summer. Dometic fridge doesn't work well enough on gas, so gonna use dorm size fridge that draws 15 amps. I have two 90 amp deep cycle batteries for 180 amp hrs. and 2k inverter. In therory, will they last about 10 hrs ? I will use generator a couple of hrs a day morn and even. to charge. Sound reasonable, or am i dreaming ?

MartyinSC · 02-27-2017, 07:53 PM

I'm not a battery/inverter guy, so I'll defer to others on your main question. I'm surprised by your belief the Dometic works better on AC. Both are used to create heat to boil the ammonia solution that provides the evaporation, and thus, the cooling. Something is wrong if an electric heating element heats the ammonia better than an actual flame. Get a tech to check your fridge gas flame. When we are on gas, I have to set the temperature less cold.

2slick · 02-28-2017, 03:38 AM

I would agree with Marty. Might need to clean the orifice. Also be sure the gas valve is open completely. 1/4 turn valve IIRC.

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gregtx · 02-28-2017, 07:18 AM

Yes, I have cleaned flame area, vac ed, blown, swept, and have a blue flame. Fridge works somewhat on gas, just not well enough to keep milk, mayo etc cold. Works good enough for eggs or butter. Left Ruidoso, headed for Pflugerville, fridge was 38, and gained about 1 degree / hr. Goes up to 50 or so and holds there. Know people with rvs that are 40 yrs. old and worry about fridge freezing, not being to warm. Of course, service says nothing is wrong.

**Lloyd** · 02-28-2017, 07:41 AM

It's possible the thermister is going bad. They are relatively cheap and simple to change if that turns out to be the problem.

campingcpl · 02-28-2017, 10:18 AM

This calculator might help you out. You will need to know the wattage of everything that will be powered by the inverter. Your fridge manual or the tag on the fridge should have a wattage on it. Personally I don't think you will have to much of a problem. We have ran a 50" led TV (roughly 50 watt) and a 10" table top fan (roughly 25 - 30 watt) off of our inverter for more than 8 hours and only seen a drop of about 1/2 to 3/4 of a volt. Your results might vary. The battery bank we are using I believe is around 120 amp hour. I would think your dorm fridge would be somewhere around the 30 watt range give or take. I hope this helps you out.

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**DavisK** · 02-28-2017, 04:07 PM

I have to agree that my Dometic refrigerator works just as well on gas as electricity. I can freeze ice cubes and keep ice cream hard in the freezer. I can't tell any difference between gas or shore power.

Dayle1 · 02-28-2017, 05:08 PM

Where to begin?? First, you can't drain the batteries more than about 50% before recharging them. I don't know the exact number, but draining them too much shortens battery life. Also, the dorm frig won't run all the time, so you have to estimate the duty cycle. Then it probably doesn't use 15 amps at 120v AC, so where did the 15 amp number come from?? Then the converter in the trailer is not the most effective way to quickly recharge batteries, a good automotive battery charger should be used. I turn the converter breaker off and hook the charger directly to the batteries. Also, generator output is reduced at high altitude and heavily discharged batteries will be a heavy load on the charger or converter.

But before going down that road, you should really try and get the RV frig working better. First, is it in a slide out or not?? If it is in a slide out, then it is supposed to have a small fan, controlled by a thermistor to aid in air flow. Maybe it is not working? If it is not in a slide out then it won't have the fan, but adding one will help with air flow and may solve your problem. The other issue is many manufacturers are guilty of doing a poor job of actually configuring the frig compartment to comply with Dometic's/Norcold's guidelines for proper ventilation. If there is too much space between the coils and the cabinet walls, air flows next to the coils rather than thru the coils (I may be wrong, but as I recall, the space is supposed to be 3/4" at the coils). Finally, there is inadequate insulation around the frig, too much heat is lost thru the cabinet walls and reduces the 'chimney effect' for good ventilation. On my trailer, the air conditioner thermostat was mounted on the cabinet wall, the lack of insulation between the frig backside and trailer interior screwed up the thermostat all the time. I ended up pulling the frig out, insulating the backside of the cabinet walls with 3/4" rigid foam. This fixed my air conditioner problems and made the frig operate much more effectively. I have no problems with my rv frig running on propane or electric here in central TX or at Cloudcroft at 9000 ft.

gregtx · 03-02-2017, 06:27 AM

Still under extended warranty. Don't want to screw up warranty by doing more than clean up around flame. Of course, service says there is nothing wrong with fridge, gas or shore power, so won't do anything. Never ending battle.

Dayle1 · 03-02-2017, 10:46 AM

Quote:

Originally Posted by gregtx

Still under extended warranty. Don't want to screw up warranty by doing more than clean up around flame. Of course, service says there is nothing wrong with fridge, gas or shore power, so won't do anything. Never ending battle.

Warranty isn't doing much good if dealer can't fix the problem and you are spending more money on an alternative. Besides an aftermarket frig fan shouldn't affect warranty. This is a common upgrade for many owners with marginal cooling. Worst case you loose warranty coverage on the frig. But that doesn't affect the rest of the trailer.

MartyinSC · 03-02-2017, 10:58 AM

Time to squawk louder, and to more people. Tell the dealer again you're not satisfied. Contact Dometic. There is always Good Sam and Trailer Life. They're pretty good about dealerships that are hard to move. Face it, based on the response on this board alone, you have a problem. It could be simple (flame adjust) or complex (re-structuring and/or insulating the box the fridge is placed into). Believe me, a properly operating fridge is a joy, not a hassle, or something that has to be worked around.

fredtx · 03-03-2017, 09:01 AM

Dayle1 has the right idea. We run our fridge on gas almost all the time. It cools as well as it does plugged in. Yours should too. I think you might try talking with a Domestic engineeer, they have pretty much seen it all. You can put together an endless run of self serving soultions, We just left a camp where a family had a full size freezer mounted on the back of their 5th wheel. Had its own awning and separate cord to the pedestal. Frozen pizza for days. Let us know if you find out whats wrong with the fridge. Happy Trails

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gregtx · 03-04-2017, 07:58 AM

Hound dealer to get something fixed ? Lol....... Bought rv at Vogt in Ft. Worth, called them and no longer sell Crossroads, said they don't service Crossroads anymore. Can't make this stuff up.

Dayle1 · 03-04-2017, 08:07 AM

Quote:

Originally Posted by gregtx

Hound dealer to get something fixed ? Lol....... Bought rv at Vogt in Ft. Worth, called them and no longer sell Crossroads, said they don't service Crossroads anymore. Can't make this stuff up.

Call CR and ask for the name of a dealer in your area that can service your unit.

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