2-way fridge questions

mikeandkim

I'm looking hard at purchasing a 2023 T@B 400 Boondock and have a few questions about the 2-way fridge.....

1) How level does the fridge need to be in comparison with the 3-way?
2a) How long at a time will the fridge run on DC power? (I'm concerned with overnight stays in rest areas)
2b) Also, should I plug in at home if I wish to run it for longer periods?
3) Will a gallon of milk fit or only a half-gallon?
4) How many bags of frozen veggies do you think would fit in that small freezer?

Thanks!

Mike

bergger

I don't have any specifics on that exact fridge but can give my experience based on the compressor fridge I currently have. 

1.  Compressor fridges can run when way off camber.  The one I have will run up to at least 30 degrees off camber.  You won't have to worry at all about it not running due to the level of your T@b unless you flip it over.
2.You should have no problems with overnight stops. However many variables will impact this to include outside temps and humidity and the temps inside the trailer.  However I can confidently say the fridge should run for several days on the single lithium battery in the trailer.  Also with the solar onboard that will help a ton during the daylight hours.  I can run mine off a Jackery 1000 for at least 4 days here in Colorado with no additional charging to the Jackery, which is a smaller battery than what is in the T@b. 
3.  No clue on that one but what we do in our 3-way is pour milk and juice into Nalgene containers that fit well in the fridge. 
4. You can't fit any frozen veggies in the freezer.  It only has room for ice cubs used for fireside cocktails! 

Denny16

We ran our two-way fridge overnight on battery, no issues, and battery was recharged afterwards by mid day.  The new larger 2-way fridge on the 2022 and 2023 TaB400’s have extra room.  Also, the 2023 TaB400 is fitted with Lithium batters vs the AGM used previously, which will extend the run time.  If you do no opt for,them4-battery factory battery package, add a second Lithium battery to the one battery package option, and a Victron Mart Shunt, both of which can be dealer installed.  Two 100-amp lithium batteries should give plenty of power for occasionally off grid overnight stays.  
 Cheers 

Jetman

Please I am a novice at this and have read the Norcold manual, no help there!

I am used to the 3 way fridge in my old 320 that you had to set the master switch to the desired run function manually.

Does the two way fridge distinguish by itself what power you are using ? And set itself to Ac/DC? The only manual switch I found is for the temp setting inside the refrigerator.

help, as do not want to mess up!

Jetman

Binghi

The two-way fridge is a DC appliance, even if you are running on shore power. The only adjustment is done via the manual temperature switch that you mentioned. I turn it all the way to the off position when storing the trailer; on the road, I put the temperature setting at about 2 1/2.

Denny16

The AC/DC fridge is a step above the 3-way.  You only need to pre-cool it on AC, to save battery power, by plugging the trailer into shore power.  After it is cooled down, use it and forget it.  No maintenance, other than to keep it clean.  No power source selection, no having to have it level.  It is a compressor fridge like the one you have at home.

Edit:  I would get a fridge thermometer to monitor the fridge’s temp, set the fridge thermostat to 2-3, depending on the ambient temperature to keep the fridge at food safe temps.
 Cheers 

Mickerly

It's actually wired as 12v DC. So, whatever power source powers the trailer will power the Fridge. We also set 2.5 as the summer setting.

Denny16

Good point Mickerly, the new mode 2- way fridge, is DC only.  The original 2-way fridge did run either on AC or DC, depending on if shore power was connected.  Not sure if this fridge converted the AC to 12VDC, but it was connected to the AC mains as well as rhe DC circuits.  Still the unit was plug and play, and would auto-detect which power source was connected to the fridge.
 Cheers 

Mickerly

I looked back through 2018 to present. The 2-way refrigerator is wired DC only from the factory. The 3-way has a 120v CB for AC operation and a DC fuse for DC operation. Sources are the diagrams on the forum and current and historical owners manuals on the NuCamp site. Having had my 'frige out (2018), I know it is wired DC only. And there is no AC CB for the refrigerator.

This is the preferred method of wiring the appliance. When shore power is available, it will supply 12 volt DC. When not connected the battery will supply 12 volt DC. Power is not interrupted when connecting or disconnecting external power. The appliance doesn't need to be off when connecting or disconnecting power like the Alde does.

In the grand scheme of things, it doesn't matter. The 2-way compressor refrigerator will always be powered when 12 volt DC is available from any source. Therefore, no switch for AC to DC. The 3-way absorption refrigerator will always work better on propane. Propane is a stronger and less expensive source of heat.

Horigan

Sounds like we should just be calling them DC refrigerators, or DC compressor refrigerators, instead of 2-ways then.

Pintoplumber

@Horigan I would agree. The compressor is 12 volt and the only line feeding it is12 volt.

bergger

I always refer to them as compressor fridges to avoid the 12v/120v  2 way confusion.  To me a 2 way fridge is an absorption fridge that runs on either inefficient 12v or on 120v, like a 3 way fridge without the propane option. 

Mickerly

I agree. The words "compressor" and "absorption" should be used instead of the number of methods or receiving power.

Marceline

Horigan said:

Sounds like we should just be calling them DC refrigerators, or DC compressor refrigerators, instead of 2-ways then.

Norcold does sell the AC power supply for the 2way fridge as an option (as least for the older model in my 2013 CSS).

AndreO

@Mickerly
Interesting, my 2018 400 did come from the factory with both ac and dc connected. The ac cord was pluged into into an ac receptical under the bed. You can see it in the attached picture wich was taken before I reconfigured everything during my lithium install.

I do however find that the fridge runs cooler on the the same setting when on ac. 

rfuss928

Pintoplumber said:

@Horigan I would agree. The compressor is 12 volt and the only line feeding it is12 volt.

The lower picture shows a common connection socket for a 120VAC cord in the upper right corner.

Pintoplumber

Doesn’t  the optional 120V power supply cord reduce voltage down to 12V? It’s still a 12V compressor.

Mickerly

Yes it does. It could have been wired for 110, but it converts to 12dc right there.

Denny16

Our our Jan 2018 build TaB400 has both AC and DC connected to the Norcold 2-way fridge.  I assumed it converted the AC feed to DC to run the compressor, so it is still a 2-way power source (AC/ DC), regardless of how the appliance converts the power.  The newer TaB400s have a Isotherm Elegance 65 DC fridge installed and it is connected to the trailer’s DC power source only, so this is a DC (single lower source) fridge, and not a 2-way.  The Isotherm is also a little larger, and uses slightly less power when running, with its newer Danfoss compressor. 

Cheers

dnordahl1

Does the Isotherm require a different cabinet opening, or can it be installed as a drop in replacement for the Norcold?

Sharon_is_SAM

https://tab-rv.vanillacommunity.com/discussion/11273/replacing-norcold-3-way-fridge-with-isotherm-2-way/p1

dnordahl1

@Sharon_is_SAM Thanks for the helpful link. I believe I have the Norcold Nr751BB. Looking at the dimensions of the Isotherm Cruise Elegance 65, it has similar dimensions which would not require major cabinetry work should I ever need to replace the Norcold. It looks like the design of the Isotherm makes more sense having the heat producing components on top instead of underneath.  From what I've read they use a more efficient compressor as well.

And I see they make a drawer version with similar dimensions though more expensive. 

Mickerly

The Norcold Nr751 (T@B400) and it's little sister the Nr740 (T@B320) both use the Danfloss compressor, just like the Isothrem.