New Fridge Advice

[rockbender]

WOW! So does that mean that you are only pulling about 5a in a 24 hr period? That almost seems impossible, but fantastic if it is true. I thought I was originally getting an ASU fridge but due to the mix up took a discount on what was delivered (non-ASU) and just decided to deal with it. Sounds like the ASU really makes a difference!

I'm probably still in break-in period and also need to increase my air flow/ventilation to make the fridge run more efficiently, but I don't think I'll ever see your power efficiency. Very impressive.

[Ketcham]

At first I thought the xantrex was underestimating. However the draw from the lights were consistant with rating. The fridge is well ventillated in the back. I can post pictures if interested. esentially there is a 3-4" gap on the side in the back from the wall to the side of the cabinate.

[frenchy]

Ketcham, I would like to see photos of how your fridge is ventilated. I was planning on using 1/2'' insulation all around the fridge but didn't plan on much open space. Where is the best spot for the ventilation to be? In the back, side, below, above?

Thanks.

[frostyone]

Ketcham,

The ASU sounds sweet! Where in PDX are you? I saw a white SMB in Gresham today, maybe it was you?

[Ketcham]

Yes, we are in Portland but not in Gresham today. If you ever need work I recommend Rob's 4WD Diesel Center in Clackamas. I am having them undertake a big project. He is willing to place a 5.9L cummins in the van but that is a topic and project for another day. Quadvan owner I guess is also undergoing this project as well.


11955 SE Highway 212
Clackamas, OR 97015
(503) 650-6101

Regarding the fridge. There is a 3" gap and 7" of wood that meets wall of the van at the top. The compressor is well ventilated. The internal ASU unit needs to be secured to the fridge module in the back near the compressor...I used ties and was successful.

viewtopic.php?f=13&t=3075 is a better solution.

Here are the pictures: (prepare to place you monitor on its side)

[coyotearms]

Originally Posted by Ketcham

Sorry for the crazy late reply. Regarding power usage. My Isotherm in ASU use was 0.8A at startup (warm refrigerator) or engine running and not in power conservation. The unit would be running at draw .4 amps while compressor is running with ASU on at at night...no solar, no engine running. This was rated from my xantrex pro. My duty cycle was far less than 25%. The unit is so silent, this is likely an underestimate. We however live in the Pacific NW and I live year around in Ibex wool, it seems. The demand on the fridge is less than the rest of the US.
Hope this helps.

This is very old post but I ran across it while researching portable fridge/freezers. It seem like a misleading claim in that it does not reflect what the power usage would be over a 24 hr period. If a fridge has some system to use more energy when there is more power (like essentially putting in a bunch if ice cube trays of liquid water in the freeze section while driving (or with solar when the sun is shining) and then put the frozen trays in the refrigerator section at night), then one would see less power draw at night while the ice is melting. It is a nice approach, but it does not mean the fridge is any more efficient overall that one without ASU. With or with out ASU, enough consecutive very cloudy or winter days camped in one spot the result would be the same---ya' got'a recharge them batteries to keep the fridge running!

Without even looking at the specifics of an ASU design, I am going to guess that space is taken up to do it's thing is just like the ice cube trays---they take space away from more ice cream . . .

[1der]

Read thru this thread and saw the .4a draw claim per Xantrex. Possible that was at 120v, so equivalent at 12 volts was ........... 4 amps?? This is after few glass of wine so I apologize for messing up my wine and watts and vino and volts. ??? (note to self: blame Chris T, if wrong)

[JWA]

Wine and watts, volts and vino..........that's my new motto!

[daveb]

Originally Posted by 1der

Read thru this thread and saw the .4a draw claim per Xantrex. Possible that was at 120v, so equivalent at 12 volts was ........... 4 amps??

I would think that's the case 48w or 4 amps @12v. Not sure if that accounts for the inverter load itself which can be as high as 3 amps. My inverter gauge is on the inverter control panel and my DC link 10 is how I normally test DC loads.
But even if you measure amp hours (or watt hours) at 120 or 12v, how well insulated the unit is and how warm the vans inside temp is are factors needed to be taken into consideration. It's almost impossible to run tests unless the units are in a controlled environment at a specific place.
However I do think ASU units can be more efficient. I don't really care cause I have solar, two 4-D's and don't stay put for long lengths of time in camp.
I do try to keep the breaker off the the fridge if the inverter is being used for the obvious reason.

My new Norcold pulls twice the amps than my old unit did and I was worried about that. But it runs a quarter percent of the time compared to the old one. So overall I'm hoping it will be more efficient than the 2006 Norcold. My fear is the insulation is no better in the new unit and in hot weather it will cycle more. Time will tell

[Scalf77]

Technical data from the Isomtherm site
Voltage 12 or 24 volt DC also AC/DC as an option
Power consumption when compressor is running: CR 42, 49 & 65: 2,5 - 2,7 A at 12 V (half at 24 V)
CR 85: 3.8 - 4 A at 12 V
CR 130: 4.7 - 5 A at 12 V
CR 130 Drink: 5- 5.3 A at 12 V
Average consumption: CR 42 & 49: 0,6 A at 12 V
CR 65: 0.7 A at 12 V
CR 85: 0.8 A at 12 V
CR 130: 1.2 A at 12 V
CR 130 Drink: 1.4 A at 12 V
Average consumption measured at 43°F in the refrigerator and 72°F ambient temperature.
The average consumption is much dependent on the way the fridge is used and how well the ventilation
is working.
Compressor: Danfoss BD35F

Explanation of how Isotherm works:
The green light indicates that power is being supplied and
the refrigeration program is activated.
- When the engine is running and the voltage supply
(measured at the electronic unit) is above 13.2 (26.4)
volt, the compressor starts to supply cooling energy to
the holding plate. It starts within the first 30 seconds and
operates first at low speed with the yellow “Economy”
indicator lit.
After less than half a minute, the speed of the compressor
and the fan increase by 75% and the red «Freeze» indicator
light comes on. This operation condition is maintained until
the holding plate is completely frozen at approximately 7°F.
This can take 20 to 40 minutes depending on the model,
ambient temperature and refrigerator size. On reaching
this temperature, the compressor stops and the red light
goes out. When the temperature of the holding plate rises
to 14°F the compressor restarts to charge the holding plate
and the red light comes on again. This process is repeated,
keeping the holding plate at its optimum efficiency level.
When the engine is stopped, the compressor also stops
shortly afterwards.
When the engine is stopped and the battery voltage is
below 12.7 (25.4) volt, the surplus of refrigeration energy
stored in the holding plate is used first.
Only when this has been consumed does the compressor
start. The yellow light indicates that it is now running, in
the first hand, at its low ”Economy” speed to ”top-up”
the holding plate only and maintain the refrigeration
temperature. This condition starts when the temperature of
the holding plate rises to 30°F and stops when it reaches
economy level of 21°F.



I expect 1der is correct and he was using the .4amps off of 120. The 24 hour average consumption is measured at 43°F in the refrigerator and 72°F ambient temperature. I believe we are talking about a CR 85 so that would be .8 x 24 or 19.2 amps, That is still a respectable savings in power, they son't really tell you how long before the ASU benefit goes away. But I expect the second 24 hours is not as good.

-greg