Date: Tue, 20 Sep 2011 07:25:08 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Vitrifrigo/Truck Fridge power usage
In-Reply-To: <14AE3CD9-467F-49F4-805B-43F817E18F2B@SHAW.CA>
Content-Type: text/plain; charset=windows-1252; format=flowed
Hi Phil,
No one should think I am attacking the Vitrifrigo, -- I have one, I like
it a lot. And my "horse pucky" comment was not addressed to you, but to
the explanation the rep gave.
A "couple of amp/hrs give or take" is something I DO pay attention to,
because some of my camping trips are in hot weather for many days,
situations where, either due to clouds or trees (the sun is at a low
angle these days and a forest to the east or south means that I may not
get sun until noon) my solar panel array may not get enough sunlight
during the day to re-charge the battery back to full before the next
sundown, so I can operate at a deficiency, which after a few days, will
result in a battery more depleted than I feel comfortable with. I like
to baby my battery. I like to be able to bring it back to 100% before
dusk every day.
That five-night camping trip to East Park Reservoir where it was in the
100+/80+ daytime/nighttime temps was one such trip. The refrigerator was
working pretty hard and my 6.5 A/h panel set was not quite up to the
task of fully-charging the battery by sundown, leaving it 4 A/h or so
less fully-charged than the previous day.
I could get bigger panels, but that was an unusually long and hot time
and the battery had enough reserve to accommodate the shortage.
As I mentioned, the reefer ran pretty close to full-time in the heat of
the day which was not Richard A Jones's experience with the same reefer
in similar conditions. But as I also mentioned in my original post, I
had the reefer set to the low-current mode, not the midrange mode it
ships with, and this correlates with Dennis's and my guess that that the
compressor has to run for a longer period of time at that lower setting
to achieve the same amount of cooling.
Setting to the medium or high setting would probably reduce run-time,
and it might have no effect on overall consumption during any given
24-hour period. Or maybe it might.
My guess is that efficiency would be a bit better, and I think now, that
after I've run the refrigerator a couple years set this way and have
developed a feel for its power usage, I would notice the overall effect
of a change. It's an experiment worth doing, and I shall.
That said, I still don't buy the rep's explanation. I've had plenty of
reps in the consumer electronics world who didn't know how a flashlight
worked, and made up answers to technical questions. Out here on the West
Coast, there was a joke:
"What's the definition of a rep?"
"I don't know the answer, I'll have to call the factory but they are on
the East Coast and closed right now so I'll get back to you tomorrow."
(This being the typical answer a rep would give if asked a technical
question -- if you have to explain a joke . . . )
Thermostats are cheap cheap cheap. Aquarium heaters use them, Norcold
and all other refrigerator manufacturers use them. Running the
compressor harder or softer is no way to compensate for thermostat
sensitivity, that's done in the front-end circuitry that the thermostat
is connected to.
I'm still sticking with my theory that because the market only looks at
current, and not 24-hour power usage (under some standardized
conditions), VF and others are compelled to promote low current numbers.
I, and others, have measured the actual current consumption for this
unit and have found their claims to be understated, that even on the
low-current setting it draws more than claimed.
I asked the distributor about this ("Hey, how come the current is higher
than the brochure says?") and his response was to set it to the low
setting. He didn't give an explanation, and didn't seem to want to find
out. Factory was probably closed when I called.
And that's how I set it. The current is lower than the default setting,
but still higher than the published claim, but the unit works just fine,
probably at the expense of longer compressor run time to compensate for
the lower current.
But who cares if the daily power usage is satisfactorily low?
You know me -- I like to try to figure out things. I ask dumb questions.
Why does VF provide three settings? The thermostat thing doesn't make
sense to me. The higher settings probably reduces run time which could
be important in a closed vehicle baking under the desert sun in some
sand state. Different settings may change the overall efficiency (A/h
per day). Or maybe not.
But really, my original post about the power usage of the unit was not
meant to stir controversy, it was just a report that others might find
useful for determining how much battery they would need if they camped
in similar conditions.
At the end of that East Park Reservoir trip, I took down the solar
panels at sundown on the eve of our departure. By the time we left,
midday the next day, the 130 A/h deep cycle battery had 56% capacity
left (73 a/H), IOW the reefer had used 57 A/h from sundown to midday the
following day. 28 or so had been consumed during the nighttime, the rest
during the following morning when the day was heating and no panels were
connected.
That was about as tough a test as I'd care to give the thing. It was
pretty darn hot. It did better than we did, we were pretty wilted at the
end of the trip.
The VF is a wonderful little unit.It has never run out of cooling
capacity even on the hottest days. Set to the 6 o' clock position, the
internal temp stays at 43F (or so, don't recall exact number) reliably
and continuously. (Mind, Mrs Squirrel likes to freeze bottles of iced
tea so she sneaks in and sets the knob to the 7 o' clock position for
faster freezage.) It has more internal room than the Norcold or
certainly the Dometic, and I find its fan noise to be easier to sleep
through than the thrum/brrrr of the Norcold's compressor (YMMV).
--
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 09/18/2011 09:26 PM, Phil Zimmerman wrote:
> Bear with me here..
>
> A Vanagon friend kept a couple of real snowballs frozen in his Gelato Cooler for me, for two days…
> The Gelato/Truck Fridge work Ok…. Who cares about a couple of amp/hrs give or take.
>
> Pz
>
> On 2011-09-18, at 9:10 PM, Vanagon wrote:
>
>> Heck, even at the "low" setting the thing makes ice cubes and keeps my food cold.
>>
>> Sent from my smartphone with tiny screen& even tinier keypad.
>>
>> On Sep 18, 2011, at 8:45 PM, Phil Zimmerman<philzimm1@SHAW.CA> wrote:
>>
>>> On Sun, 18 Sep 2011 20:34:04 -0700, Vanagon<camping.elliott@GMAIL.COM> wrote:
>>>
>>>> Well, okay -- but how do I determine a "best fit" is?
>>> ----
>>>
>>> Easy peezee rocket.
>>> You have that real cool amp/hr measuring gizmo in mellow...
>>> Try each setting on the gelato maker: high, medium and low for your particular camping
>>> situation..
>>> Over a period of time... what works as a best-fit will become apparent....
>>> Lowest overall amp draw that produces an acceptable temperature in the gelato cooler.
>>>
>>> That's my story....
>>>
>>> Pz
>>> --------
>>>
>>>
>>>>
>>>> Sent from my smartphone with tiny screen& even tinier keypad.
>>>>
>>>> On Sep 18, 2011, at 8:04 PM, Phil Zimmerman<philzimm1@SHAW.CA> wrote:
>>>>
>>>>> On Sun, 18 Sep 2011 07:27:56 -0700, Vanagon<camping.elliott@GMAIL.COM>
>>> wrote:
>>>>>
>>>>>> Right, but here's my question.
>>>>>>
>>>>>> If low current setting + longer runtime = high current setting + shorter runtime . . .
>>> in
>>>>> other words, if there is no overall effect on longterm power consumption . . . then why
>>>>> does Vitrifrigo even bother giving the option of three different levels of current
>>>>> consumption?
>>>>> ---------
>>>>> Rocket,
>>>>>
>>>>> Somewhere between your question (above) and Dennis's insights...
>>>>>
>>>>> Recalling a samba post a year ago, where a new gelato-fridge installation
>>>>> (my sarcastic name) was consuming way-more amp-hours than expected.
>>>>>
>>>>> The problem was located in the fridge thermostat. So said the factory rep. as I recall.
>>>>> Thermostats vary. Some are fast, some are slow to respond to delta-"t".
>>>>> Others are numb to respond at all.
>>>>>
>>>>> Now I'm guessing here. The three current settings are available to get a best-fit with
>>> the
>>>>> individual thermostat. Try each setting for a "best fit" to your particular thermostat...
>>>>>
>>>>> Pz
>
