Jim Gell Posted April 4, 2021 Report Share Posted April 4, 2021 I have the option of plugging our 63 QT Base Camp fridge/freezer into 12V or 120V while driving. I read the manual and could not find a wiring diagram there or any info on line, other than it has a "Kohld Polar Hermetic" compressor. I assume AC power (inverted from my 12V battery) would be converted to 12V inside the freezer to run the compressor. That would be a less efficient use of my RV's battery. Is my assumption correct that plugging the freezer into 12V would be a more efficient use of my 12V battery power? Thanks in advance! Jim Quote 2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift Passenger assist elevator to enter cab - for when we need it, or sell it? '05 Travel Supreme Select 40 RLQSO 5th wheel 2016 smart car We started full timing on December 1st 2014 Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain Not all that wander are lost - J. R. R. Tolkien Link to comment Share on other sites More sharing options...
oldjohnt Posted April 4, 2021 Report Share Posted April 4, 2021 3 hours ago, Jim Gell said: Is my assumption correct that plugging the freezer into 12V would be a more efficient use of my 12V battery power? Does the compressor operate on 12 VDC or 120 VAC ??? (my guess is 12 VDC based on what I found but I can't guarantee that) BaseCamp™ 63-quart AC / DC Portable Fridge / Freezer - 588746, Camping Coolers at Sportsman's Guide BUT REGARDLESS Obviously you would need to rectify and reduce 120 VAC to 12 VDC if the compressor requires 12 VDC but you're running on 120 VAC orrrrrrrrrrr Invert 12 VDC to 120 VAC if the compressor requires 120 VAC HOWEVER there are wasted I Squared R heat energy losses in EITHER conversion, so YES if you can run it without having to convert you save energy. John T Quote Link to comment Share on other sites More sharing options...
bigjim Posted April 5, 2021 Report Share Posted April 5, 2021 (edited) Jim and john I read the power consumption is .74 amps per hour on 12Volt. Didn't see what it was on 120v. On their site it showed reg price for the 63qt was normally over $1700. but out of stock they are less than $500. In fact I believe it was the same price as the 42qt. After double checking the 42qt shows $429.99 and the out of stock 63 qt shows $474.99. Edited April 5, 2021 by bigjim more typing screw ups Quote Link to comment Share on other sites More sharing options...
Jim Gell Posted April 5, 2021 Author Report Share Posted April 5, 2021 Thanks for the input bigjim and oldjohn. My subject line sums up my dilemma. I don't know if the compressor is 12 or 120 volt. Perhaps the most efficient use of my battery power is to power it with 12V. If it's a 12V compressor, there will be no inversion. And if the compressor is 120 volt and the freezer has to invert the 12V, maybe it's still more efficient than my big Magnum inverter. The Magnum will be running to power my residential fridge anyhow though. If anyone can confirm that the compressor is 12 volt as I am guessing, or that it's not, please chime in. Thanks. Jim Quote 2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift Passenger assist elevator to enter cab - for when we need it, or sell it? '05 Travel Supreme Select 40 RLQSO 5th wheel 2016 smart car We started full timing on December 1st 2014 Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain Not all that wander are lost - J. R. R. Tolkien Link to comment Share on other sites More sharing options...
bigjim Posted April 5, 2021 Report Share Posted April 5, 2021 I could not find where it flat out said but to have that low consumption rate on 12V it would almost have to be a 12V compressor. I think I am correct that a lot of household compressor now have 12V compressors but I am not sure and do a soft-start up of the compressor. Quote Link to comment Share on other sites More sharing options...
Lou Schneider Posted April 5, 2021 Report Share Posted April 5, 2021 (edited) A few minutes with an AC/DC clamp on current meter will show which power source is most efficient. The price of decent meters is coming down, I've had this one for about 6 months, it works great and at less than $50 including everything else it does, it's a steal.https://www.amazon.com/dp/B07Z398YWF Edited April 5, 2021 by Lou Schneider Quote Link to comment Share on other sites More sharing options...
Ray,IN Posted April 6, 2021 Report Share Posted April 6, 2021 I have an older model of this Norcold portable freezer/refrigerator. Perhaps the technical details offer a clue to this discussion. It is plugged into both 12VDC and 120VAC constantly and runs on whichever power source is convenient when on shore power. Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
Jim Gell Posted April 6, 2021 Author Report Share Posted April 6, 2021 Lou, I have a meter but don't know how I would use it. My first thought is, I could unplug from shore power and turn off everything except the freezer and measure the amps coming across the positive battery cable while running off 120V through my RV's inverter, and compare it with running off the 12V directly. I should remove the frozen food and let it warm up inside a bit to make sure the compressor runs during each test. All that seems like too much of an effort. My second thought, and perhaps what you were thinking, is that there is probably a easier way to figure it out using a meter. If I knew the efficiency of my RV's inverter, a formula might be applied to compare the power consumed at the freezer itself when running on 120 V supplied by battery power through the RV's large inverter vs 12V directly off the battery. That might tell us which is more efficient. I missed that day in electrics class though. Someone would have to tell me the formulas to use. Ray, if I plug our freezer into both 12V and 120V it will default to operate on 120V. When the 120V is interrupted it will automatically switch over to 12V. Then when 12V is restored it switches back. That makes sense for most applications. When we are running off 120V, the cord is on a circuit connected to the big RV inverter. When shore power goes off, the inverter kicks in fast enough that our clocks don't reset. If we had both cords plugged in, it would run off the 120V even after the shore power was interrupted. In those RV Parks that I am paying by the watt for shore power, I prefer to operate the freezer off the battery when it can be recharged with our solar panels. My question about what voltage the compressor runs on has to with wanting to be able to get more days to run the freezer, residential fridge, and other things like the TV, off my battery when it's cloudy or rains for several days and we don't have shore power. Quote 2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift Passenger assist elevator to enter cab - for when we need it, or sell it? '05 Travel Supreme Select 40 RLQSO 5th wheel 2016 smart car We started full timing on December 1st 2014 Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain Not all that wander are lost - J. R. R. Tolkien Link to comment Share on other sites More sharing options...
Kirk W Posted April 6, 2021 Report Share Posted April 6, 2021 Jim, what Lou is suggesting is a clamp-on meter that can measure the current (amps) thorough the wire without breaking into it. Quote Good travelin !...............KirkFull-time 11+ years...... Now seasonal travelers.Kirk & Pam's Great RV Adventure Link to comment Share on other sites More sharing options...
palmeris Posted April 6, 2021 Report Share Posted April 6, 2021 Have you tried calling them 1-800-251-0001 or emailing them https://www.mrheater.com/contact-us with your questions? Quote Link to comment Share on other sites More sharing options...
hemsteadc Posted April 6, 2021 Report Share Posted April 6, 2021 (edited) 18 hours ago, Jim Gell said: My question about what voltage the compressor runs on has to with wanting to be able to get more days to run the freezer, residential fridge, and other things like the TV, off my battery when it's cloudy or rains for several days and we don't have shore power. It seems highly unlikely there would be an inverter in the unit. Edited April 7, 2021 by hemsteadc Quote Link to comment Share on other sites More sharing options...
Ray,IN Posted April 7, 2021 Report Share Posted April 7, 2021 6 hours ago, Kirk W said: Jim, what Lou is suggesting is a clamp-on meter that can measure the current (amps) thorough the wire without breaking into it. Yep, for both AC and DC if one buys the right meter. Quote 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG retired;Good Sam Life member,FMCA ." And so, my fellow Americans: ask not what your country can do for you--ask what you can do for your country. John F. Kennedy 20 Jan 1961 Link to comment Share on other sites More sharing options...
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