Absorption fridge 2 way vs 3 way

[cptqueeg]

Gathering info for a TC build and would like to hear from the experts. Planned usage is non-electrified campsites, primarily boondocking. 4th of July through Labor till we'll be hiding at home so shoulder seasons limit solar at times, due to shorter days, cloudy conditions, shaded campgrounds, and heavy energy use during offseason for heating is expected. For instance we have a weeks reservation in mid-October at Yellowstone for 6 nights in my current setup, a FWC Hawk.

I will have propane on board and a propane fueled Honda 2200 if there is any hint of cold or heat(will have AC.) The build is specced out currently w an inverter and all the required components of a top notch solar system. (Of course seeing how the generator would be with us most of the time expense of an excellent solar system could be revisited as well.)

My questions is would a 2 way fridge be the way to go given the inferior 12v performance in 3 way fridges considering my planned build and anticipated camping conditions?

Thank you.

[Boon_Docker]

For the small amount of propane that is used I won't bother with 12v operation while traveling.

[pianotuna]

My absorption fridge works well on the 12 volt setting--but ONLY if I'm plugged into shore power. That kind of defeats the purpose.

It would take a dc to DC charger with a rating of 40 amps, and 50 may be better--my fridge draws 34 amps when on 12 volt.

[cptqueeg]

VE3ESN wrote:

cptqueeg wrote:
So far I gather the need for 12v on an absorption fridge is useful to travel instead of burning propane if there is no inverter to run a 3 way on 120v.

In my case a DC-DC charger will take care of the fridge en route via 12v or 120v w the inverter saving the propane for actual camping and eliminating any issues w flowing propane and an open flame.

What do you mean by a DC-DC charger? The fridge runs directly off the house battery when switched to 12 V, so no "charger" is required. Otherwise, you are correct in your assessment.

DC-DC charger from alternator to supply the house batteries while driving.

[wa8yxm]

On electric the fridge draws about over 200 watts On the model I had it was a 5 amp fuse) note that it really needs 350-400 to do the job right

i'd go with 2 way

[VE3ESN]

cptqueeg wrote:
So far I gather the need for 12v on an absorption fridge is useful to travel instead of burning propane if there is no inverter to run a 3 way on 120v.

In my case a DC-DC charger will take care of the fridge en route via 12v or 120v w the inverter saving the propane for actual camping and eliminating any issues w flowing propane and an open flame.

What do you mean by a DC-DC charger? The fridge runs directly off the house battery when switched to 12 V, so no "charger" is required. Otherwise, you are correct in your assessment.

[cptqueeg]

So far I gather the need for 12v on an absorption fridge is useful to travel instead of burning propane if there is no inverter to run a 3 way on 120v.

In my case a DC-DC charger will take care of the fridge en route via 12v or 120v w the inverter saving the propane for actual camping and eliminating any issues w flowing propane and an open flame.

[VE3ESN]

My 2 cents worth: The 12 V function on an absorption type fridge is used when traveling, as many, including me, don't like a flame (albeit a small one) to be on when in motion. However, propane is very useful when off-grid. It's very efficient, and completely silent. As far as when the vehicle is in motion, you can run the fridge off 120 volts AC if you have an inverter. This provides better efficiency than 12 V, and it's basically "free power". So, to conclude, a 2-way (120 volts AC and propane is what I'd use.)

[valhalla360]

Unless you accidentally overbuilt your solar system to where you need to burn off the extra electricity (or maybe if you are on the road 8-10hr per day, so the alternator provides free power)...12v operation makes no sense.

On Grid, use 120v.
Off Grid, use propane.

Where 12v can make sense is if you go with a 12v compressor fridge.
- Our 12v fridge rated at 30w once it's down to temperature.
- A 12v heating element for a 3way fridge will run 150-200w and if it's on it's drawing that amount. Given the slow cooling of an absorption fridge, I would expect it to run a larger percentage of the day.

[jdc1]

Running a fridge on propane is cheap.

[corvettekent]

We boondock four months a year and our fridge is always on propane. We have a 2 way fridge.