2-way refrigerator operation without a battery

[DieselBurps]

I have a basic question I can not find the answer to.

I have a Dometic 2 way fridge (propane/120volt) in a 1985 Airstream. I can not get the fridge to run on either 120 volts or gas.

I do not have a battery at this time.(I am on shore power)

Do I need a battery to run the fridge even though I am hooked up to shore power?

Is the battery required in order to "complete the circuit"?

I assumed since I am on shore power the fridge should work either way even though I do not have a battery.

[Old-Biscuit]

Why reinvent the wheel.....just put a cheap 12V battery in and be done with it

Simple.........

[BFL13]

So get one of these instead of a battery and another charger, and disconnect the Triad's red wire from the fuse panel and the white wire from ground. Note this converter cost is about the same as a battery's and no shipping cost it says.

Now run a wire from the positive terminal of this converter to the fuse panel to where the Triad's went, and a wire from its negative terminal to that ground connection the Triad used. #8 wire would be ok.

https://www.boatandrvaccessories.com/products/powermax-pm3-45lk-45-amp-12-volt-power-supply-with-led...

[BFL13]

Why does it need 12v input from a battery to operate?

http://web.archive.org/web/20200228080754/http://parallaxpower.com/wp-content/uploads/sites/8194/201...

Edit--found this for the 900 (and 700 I think)

Q. What happens when the battery is removed?
A. When the battery is removed from the vehicle, you will experience dim lights and possibly a humming
noise coming from your radio. Parallax Power Components L.L.C. does not recommend operation without
a battery connected to the system. If connected to 120 VAC at all times. Parallax Power Components
L.L.C.’s model SB100 simulated battery may be installed in place of the vehicle battery

[wa8yxm]

Though the fridge COOLS with eithe 120vac or Propane
It uses 12VDC to control operations.

You get that from either the battery or a "Converter" Sounds like the converter is toast as well as the battery missing.

You can use a small 12 volt power supply (Sold to radio operators) at least 10 amp but if your lights and roof fan do not work the fridge and most likely the water and even the air conditioners (in most cases) will not either. Nor the Furnace. all use 12 volt for control.

[jdc1]

The battery does not need to be a good battery. It can be as dead as a door nail. But one has to be in place for the converter to operate properly.

[MrWizard]

RLS7201 wrote:
1985 is probably stand alone propane, just like a home water heater. No 12 volt required.

Richard

Your thinking 1970's and earlier
By 1985 everything had electric ignition and 12vdc control boards

[BFL13]

http://techsupport.pdxrvwholesale.com/wp-content/uploads/2017/09/Dometic-Refer-Model-RM2820-Installa...

Seems a 1985 airstream will have a Dometic 2820 two way as OEM. (some googling to find that)

[MEXICOWANDERER]

If the unit has any pilot control lights outside, then you need 12 volts for it to run.

[dougrainer]

vintage 1985 is just when Dometic came out with the AES model refers. AES stands for Auto Energy Select. They had a an ON /OFF switch with an indicator light. MANUAL Dometic Models, you had to HOLD the Pilot button and then continually push a Manual Piezo lighter button. If the OP has just an ON OFF switch, then he has an AES and requires a 12 volt source to operate. If he has to push in a button and then continually push the LIGHTER button, he does not need a 12 volt source. AS always, MODEL is required to correctly answer his question. Doug

[pauldub]

What model is the fridge??? My '81 travel trailer had a fridge that did NOT need 12V to operate.

[BFL13]

https://www.airforums.com/forums/f449/wiring-new-converter-from-12-volt-panel-101990.html

Says what the 1985 converter is/was. In a video that came up (googling) it showed the converter in an older Airstream. That converter looked a lot like the OEM one that was in our 1981 truck camper. It was a real beast, made in Winnipeg to a British design--forget the brand name for it.

It did supply 12v when plugged into 120v. It had a battery charger section too. It made loud clunks when it switched. It was very big and heavy. Got rid of that and used a modern converter instead.

bestconverter has an article about Airstream converters. Also something on how to keep the OEM power- on indicator light working if you do swap out the old converter.

An old thread about it--it's a Magnetek 730-2

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/13748154/print/true.cfm

[pianotuna]

dedmiston wrote:

Lwiddis wrote:
Solar is the easy way to keep a battery charged.

He's on shore power, which is even easier.

Shore power is more expensive if you are camping.

[dedmiston]

Lwiddis wrote:
Solar is the easy way to keep a battery charged.

He's on shore power, which is even easier.

[time2roll]

What is the voltage getting to the fridge control board?
Does the light in the fridge work?
Is this an auto ignition fridge or do you light the pilot manually?

[Dutch_12078]

The common Magnetek converters from that era used the battery as part of the filter system to regulate the 12-volt output. Without the battery the voltage typically runs too high and may cook some fuses. Even a cheap lawn tractor battery will work well enough to operate the fridge.