1200lrim and inverter question

The other day I lost power to my motorhome while I was gone for the weekend. The fridge was set on ac instead of auto so everything went bad.  I wondered why it didn't stay on with the inverter(I have a freedom 20 and four batteries) like some other items did.  Checked the plug and it is only active with ac plugged up.  Is there a reason for this or can this reefer run on the inverter if necessary?

I can?t say for sure not knowing your coach but it is common for only a certain number of plugs to work off the inverter. This helps from killing the batteries too fast powering up a bunch of unnecessary items when the inverter takes over, and, because the refer can work off of gas there is no need for inverter power. Sorry you had to learn the hard way about keeping the reefer on auto.

Many MH's are intentionally wired with the refrigerator not on the inverter (ours was one) because it would be a large current draw and it would seem to make more sense to have the fridge switch to propane if AC power is lost.  Apparently, your fridge didn't switch to propane or the outage was long enough that the batteries ran down anyway.  The fridge needs 12V power for its controls to operate.

Agree with both of you and understand. I just curious if there was a reason for it being that way such as if it would damage the refer to run it on the inverter

It would be a real help to others if you would edit your profile and add your model, year, floorplan to your signature. 

Many if not most of the higher end pushers have the fridge AC outlet wired to the inverter AC breaker panel - yours apparently doesn't.  The AC side of the Norcold 4-door will draw about 700 watts or so - it takes a fairly large inverter to power it.

John Canfield said:

It would be a real help to others if you would edit your profile and add your model, year, floorplan to your signature. 

Many if not most of the higher end pushers have the fridge AC outlet wired to the inverter AC breaker panel - yours apparently doesn't.  The AC side of the Norcold 4-door will draw about 700 watts or so - it takes a fairly large inverter to power it.

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John's answer is also the reason why it doesn't really make sense to run the fridge off the inverter.  Why would you want to run a ~700 watt load off the inverter when that same appliance can be run on propane with significantly less electrical load.

Ours was definitely a high end DP and the manufacturer chose not to run the fridge off the inverter for this reason.  In our case we did have an AC outlet in the fridge area for running the ice maker and that outlet was wired to the inverter.  That way we could have ice while running the fridge on propane.

In my 2004 American Tradition, the outlet that runs the fridge+icemaker is actually split, with one lug powered thru the inverter and one not. The ice maker (separate plug) uses the inverter outlet while the cooling unit does not. However, the fridge cooling unit can be plugged into the inverter outlet and it works just fine. It's just a heater element, so there are no problems with a modified sine (MSW) inverter either.

The logic for this is simply that propane provides a convenient and inexpensive alternate heat source when no 120vac is available, so why tax the batteries by using inverter power? The Norcold 1200/1210 cooling unit has a hefty 120v power draw, 450 watts for the two heaters that drive the cooling process, and the heaters run pretty much non-stop in warm weather. That's about 40 amps from the batteries if powered via inverter. In comparison, the fridge barely sips LP and will run for days on just a gallon of LP.

The ice maker, on the other hand, needs 120v power to operate at all, so if you want ice when off the power grid, inverter power is the only way to go. The ice maker doesn't use 120v power for cooling - the fridge/freezer does that chore - but it needs 120v power to operate the motor and clock that manages the ice cycle. Technically that could be done with 12v powered equipment, but it is simply not economical to build a 12v icemaker just for the RV industry, so it's a standard residential fridge icemaker designed for 120v power.

So, feel free to plug your Norcold fridge into an inverter outlet if you like. If you don't use the icemaker, simply swap the two plugs. If you do need ice making capability, put a multi-tap on the outlet used for the icemaker and plug both cords into that.  Either one works fine.

Our coach is wired like Gary's, i.e. the duplex behind the refrigerator is split; One half runs from the inverter and the other doesn't. In our case, the fridge is plugged into the inverter side, and we normally run the fridge on inverter when we're driving down the road.

FWIW....  I found some info on res. fridge operation that may be of interest to off-grid RV'rs using the inverter.

  It specifies run time of typical fridges. Most fridges are energy friendly now and run most of the time... 80 to 100% of the time.

On the link here >>> http://www.geappliances.com/service_and_support/faqs/faq_refrigerators.htm
select question 3 for official details.

Thanks for the answers. I wasn't looking to run it off inverter vice using gas, I was just curious why mine was using a plug without inverter capability and if damage would occur to it if using inverter in an emergency situation since I have learned in past that it's what I don't know that destroys items in rv.  Set my frig to auto now so I don't have same problem in future.

LspTpr said:

.. I was just curious why mine was using a plug without inverter capability and if damage would occur to it if using inverter in an emergency situation since I have learned in past that it's what I don't know that destroys items in rv. ..

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The heating elements in the Norcold are resistive and could care less if the power source is pure sine wave, modified sine wave or square wave.  Inductive loads DO care (motors, transformers, etc.) about the waveform of the power source.

When we had the Norcold, we always ran it off the inverter while on the road to save propane - diesel for us is a lot easier to acquire vs. propane.

Gary RV Roamer said:

.. The Norcold 1200/1210 cooling unit has a hefty 120v power draw, 450 watts for the two heaters that drive the cooling process, and the heaters run pretty much non-stop in warm weather...

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In addition to the heating elements are the door defrosters that run periodically.

The door defroster (divider heater) is 12v powered. According to the Norcold 1200 service manual, only the cooling unit heaters and the ice maker are 120v.

Gary RV Roamer said:

The door defroster (divider heater) is 12v powered. According to the Norcold 1200 service manual, only the cooling unit heaters and the ice maker are 120v.

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How about that, makes sense.