Date: Wed, 21 Sep 2011 01:07:48 -0400
Reply-To: Karl Mullendore <tdiguru@WESTYVENTURES.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Karl Mullendore <tdiguru@WESTYVENTURES.COM>
Subject: Re: Vitrifrigo/Truck Fridge power usage
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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