

| Subject: | Re: Vitrifrigo/Truck Fridge power usage |
| From: | Rocket J Squirrel |
| Date: | Wed, 21 Sep 2011 08:12:14 -0700 |
Hey Karl, thanks for the details of your testing. That helps a lot and now I understand how to interpret your figures. It was the word "average" in the amperage rating you came up with that I was unclear on. I interpreted it to mean that one could expect a 2.1 current draw when the compressor was running on the average, depending on how the thermostat was set and how hot a day it was. Now I understand you're providing the average current draw over a period of time. I don't see the higher current at the start of the compressor run than a few minutes later, and my ammeter is a good one. Maybe they changed the design or something. My apologies if you felt like I was accusing you of BS. That was not my intent. I was trying to convey that it was from your site that I got the impression that the compressor drew 2.5A when running, and this led to a lot of confusion here when I installed the thing and found that it drew quite a bit more. -- Jack "Rocket j Squirrel" Elliott Bend, Ore. 1984 Westfalia. A poor but proud people. 1971 "Ladybug"-brand utility trailer ca. 1972 from a defunct company in San Clemente, Calif., now repurposed as The Westrailia. Sent from my kitchen. On 09/20/2011 10:07 PM, Karl Mullendore wrote: > Hey folks, if you don't want to take my independent testing for real, do > your friggin' own test! Would I post BS on my own website? Believe me or > don't believe me, it doesn't matter - but I don't appreciate the snide comments. > > Here are the facts - if they don't fit into your mindset, I don't really > givadamn. :-) > > I tested MY VF C51iAC in mid-summer weather a few years ago. Daytime temps > during the THREE-DAY test were 80-85 F. night time temps at 65-70 F. The > thermostat was set on the notch clockwise past vertical. I connected a 12V > analog clock to the fridge fan wires, so that the clock would accurately > measure the full time the fridge was running. The clock ran exactly 24 hours > in a 72-hour period. With me so far? OK. I then connected a very accurate > amp gauge between the fridge power lead and the power supply. On startup, > the fridge would vary from 2.8-3.0 amps. As it ran, the amperage would > slowly drop as low as 2.2. Since the run time far outweighs the startup > time, I figure the average amp draw to be very close to what VF was claiming > at the time, 2.5. OK - 2.5 multiplied by 8 hours run time per day = 20 > amp-hours. > > Karl > www.westyventures.com > > >>>> So where did I get the idea that the VF draws about the same as the >>>> Norcold (which I measured at around 2.5 to 2.8 A?) >>>> >>>> MULLENDORE! >>>> >>>> From<http://www.westyventures.com/parts.html> : "...the fridge >>>> operates on 12 or 24 volts ... Current draw on 12 volt is 2.5 amps >>>> (average) with an average daily usage of 22 amp-hours." >>> >>> Don't compare apples and oranges (running current vs. average current). >>> From the same datasheet I linked, the Vitrifrigo is spec'd at 470 Watts >>> average daily consumption. Now, Watts are power, not energy, so they're >>> clearly confused about units. But I'd guess they're really talking about >>> Watt-hours, which would equate to about a 1.6 Amp average draw (~54% >>> duty cycle, which over 24 hours would be ~38 Amp-hours). >>> >>> No idea what westyventures is talking about, a 2.5 A average draw over >>> 24 hours would be 60 Amp-hours??? Maybe they mean 2.5 A _nominal_, i.e. >>> the typical draw when the compressor is running? If it really uses only >>> 22 Amp-hours typical per day, then perhaps it has much better >>> insulation/more efficient compressor and a much lower duty cycle? ...or >>> maybe it's all marketing BS. I doubt a Norcold is twice as efficient as >>> a Vitrifrigo (or 50% worse?), as the numbers imply. >> >> It's all very confusing. >> >> Someone on the list needs to put a Norcold and a Vitrofrigo in an oven, >> say, 80 degrees F, and let them run for 24 hours after adjusting their >> respective thermostats to achieve the same cabinet temp. >> >> I need a grant. With that I can buy the reefers, the white lab coat, the >> clip board, the test equipment, the big oven, and a blonde lab assistant. >> >> -- RJS
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