7 replies to this topic

[stoef]

Hi there,

The stock, 3-way Norcold that came new with my '05 Hawk finally quit and I need a replacement. Has anyone dealt with this and what do you all recommend? The Norcold drew more amps than my battery could handle, even when driving so I'd like one that is efficient off 12v when driving. I would like another 3-way as I go to propane when parked. I have solar.

Thanks

[Beach]

If you want it to be efficient on 12v, then you'll need to go with a compressor type.

[ntsqd]

If you have enough solar then you won't need propane and can use a compressor fridge. I've now replaced two 3-ways with compressor fridges and consider it a step in the right direction.

 

If you're determined to use a 3 way fridge then Norcold and Dometic may be the only mfg's to look at.

 

Either way you need to know the physical dimensions of your existing fridge so that you can figure out which models fit.

[Smokecreek1]

Ntsqd has the right idea! When my 3-way frig went out for the second time, I used that as an opportunity to go solar too!  Okay, I have '05 Granby but the same idea is valid!  I had been thinking about going solar  for some time and had added a  second 100W panel the year before when the frig went out up at the Sheldon WR in Nevada. I headed home and went right to my local RV shop and ordered and had installed  a new compression frig/freezer, comptroller and second battery-went for the whole thing.  While my wallet and credit card took a big hit at the time, I have never looked back and have never been sorry.  Going solar is the way to go!

 

Smoke

[esimmers]

A 3-way fridge, also known as an absorption fridge, uses heat to provide energy needed to drive the cooling system of the fridge. It is hugely inefficient to use 12 volts from your truck or camper to provide that heat just like you'd never use your 12 volt system to run an electric heater to keep your camper warm inside. Here's why:

A gallon of propane can produce 91,502 BTUs, a measure of heat, or energy.

 

To compare propane to a battery, you have to calculate how many BTUs of heat a certain battery will produce. A KWh of electricity is equivalent to 3412 BTUs. So there's the equivalent of 27 KWh of electricity in a gallon of propane (91,502/3412).

 

A typical 12 volt camper battery is rated at 80 Amp-hours. Since watts roughly equals volts X amps, a camper battery (remember, you only want to discharge no more that 50%) can practically produce only about 0.5 KWh, something like the equivalent of 1700 BTUs. 

 

Bottom line, there's 54 times the energy stored in a gallon of propane than can practically be obtained from a typical 80Ah camper battery. No wonder we use propane, rather than electricity, for heat (unless, of course, we're connected to shore power).

[Bwht4x4]

I have an Isotherm and I'm not only impressed with the refrig unit but also their customer service.  They were a ton of help in planning my purchase.  Parts are also easy to get here:  http://www.isotherm-parts.com/.

[ntsqd]

For a 3-way can directly compare propane to 12 VDC, but not with a 2-way since the process is driven in a much different and more efficient manner.

[MountainSufi]

Howdy from Jackson Hole!

 

Never had a 3 way, but my 2 way Isotherm rocks! Driven by solar. From cursory reading, "3 way" sounds more versatile than "2 way".  However, the compressor on a 2 way is very efficient. I bought my camper used in CO, but can tell you the Jackson Hole FWC dealer prefers 2 way.

 

On a recent trip to sunny Southern UT, our 160 watt panel & 6 volt batts never got below Victron 94%. With refrig @ #2 setting and CPAP all night.

 

Ice cubes in gin & tonics make life sooooo much better!

Edited by MountainSufi, 13 May 2019 - 01:18 AM.