| small fridge question 3 amps? Really [message #105352] |
Sun, 07 November 2010 12:47  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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The revcon currently has regular dorm fridge. I recently acquired a Dometic two way (LP & AC) which i plan to install over the winter.
But yesterday in a pawn shop i found 12V tundra mini fridge. It looked brand new. The pawm shop must have thought it was an ordinary dorm fridge- i snatched it up for $49.
The paperwork says the mini fridge draws 3.2 amps at 12V
All this as a domino affect on interior design strategies;
If i could live with the mini fridge I could sustain the power with a 25 watt solar panel.
And i could put a home window AC unit in the vented refrigerator space and clean up the roof line.
A little unconventional- but......
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: small fridge question 3 amps? Really [message #105357 is a reply to message #105355] |
Sun, 07 November 2010 13:21  |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Help me understand the math-
It uses the Danfoss 12/24 volt compressor.
I only know that it gets cold and that's what hte manufacturer says it draws.
I assume it does not run all the time to maintain cold.
So is it like 4 BTU's per watt?
What's the draw of a larger RV fridge?
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: small fridge question 3 amps? Really [message #105358 is a reply to message #105352] |
Sun, 07 November 2010 13:26 |
Erv Troyer
Messages: 125
Registered: February 2004
Location: Lagrange, IN
Karma: 0
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| Dave Silva wrote on Sun, 07 November 2010 12:47 |
The Revcon currently has regular dorm fridge. I recently acquired a Dometic two way (LP & AC) which i plan to install over the winter.
But yesterday in a pawn shop i found 12V Tundra mini fridge. It looked brand new. The pawm shop must have thought it was an ordinary dorm fridge- i snatched it up for $49.
The paperwork says the mini fridge draws 3.2 amps at 12V
All this as a domino affect on interior design strategies;
If i could live with the mini fridge I could sustain the power with a 25 watt solar panel.
And i could put a home window AC unit in the vented refrigerator space and clean up the roof line.
A little unconventional- but......
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Go for it, Dave
Along with many others, we have gotten rid of the LP/electric fridge, and we are very happy with the house type unit.
The Tundra is a well-built unit, and sold mostly to the marine market. It uses the Danfoss compressor, which has been very dependable.
RE: solar panel to power the fridge - remember that it only works when the sun shines on it, but the fridge only runs part of the time depending on the cooling load required. Those are some of the variables to consider when you go this route.
If you do go with that home window AC unit (I personally don't recommend that) I would suggest you mount it as close to the roof as possible to get better circulation of the cooled air.
Erv Troyer Lagrange, IN
74 Sequoia
reo43@aol.com
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| Re: small fridge question 3 amps? Really [message #105366 is a reply to message #105352] |
Sun, 07 November 2010 14:36 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| hertfordnc wrote on Sun, 07 November 2010 10:47 |
The revcon currently has regular dorm fridge. I recently acquired a Dometic two way (LP & AC) which i plan to install over the winter.
But yesterday in a pawn shop i found 12V tundra mini fridge. It looked brand new. The pawm shop must have thought it was an ordinary dorm fridge- i snatched it up for $49.
The paperwork says the mini fridge draws 3.2 amps at 12V
If i could live with the mini fridge I could sustain the power with a 25 watt solar panel.
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You might like to look at this article:
http://www.bdub.net/Refrigeration_in_the_GMC.pdf
Helps you understand how much power you will need, even though it is about a larger OEM Norcold refrigerator.
A 25 watt solar panel will not sustain the tundra refrigerator, unless the sun where you live shines 24/7....lol.
You got a very good buy on the Tundra, very, very good.
Rob Allen
former owner of '76 x-PB
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| Re: small fridge question 3 amps? Really [message #105371 is a reply to message #105357] |
Sun, 07 November 2010 15:52 |
Bruce S
Messages: 13
Registered: November 2010
Location: Winnipeg,Manitoba,Ca
Karma: 0
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I am a newbie so bear with me. My fridge also craped out. I took it out and used a 4 cu. ft bar fridge powered by a 1000 watt. power converter. The bar fridge uses 1.6 amps at 120 v when it is running and the power converter draws 12 amps to power it (12 X 12 = 144 watts). I have 2 deep cycle batteries that together equal about 150 amp hrs (150 X 12 = 1800 watt hrs.). The batteries will run the fridge for 24 hrs,at outside average temps 70f day 40f night (1800 watt hrs / 24 hrs = 150 watt hrs per hr.)looks like the fridge runs about 50% of a hour to keep things cool. So if I get 6 hrs. of sun shine per day I need 300 watt solar panels to charge the batteries to run my fridge. Your fridge if it has the same efficiency as mine and running at the same outside temps should use about 1/4 of the watt hrs, I would suggest to be on the safe side that you need 100 watt solar pannels to power your fridge.
This is an after thought: If your house batteries are over 75 Amp hrs. you should have no problems with the 12 v fridge unless you are goining to park with no power for over 24 hrs and require the fridge to operate.
The bar fridge was a tempory thing but the extra space that became avialible for storage of long items has got me wondering that I should make make this a permanent installation. When I had the GMC MH parked and was working on it; I tried a window AC in the fridge cavity, problems: the vents on the side are not large enought and draining the condisate from the evaporizer. My 15 amp supply would trip when trying to run the 13500 btu roof AC, the window AC is 8000 BTU. and did not trip the cb. but did not have much cooling effect for 80f.
My apologizes to "hertfordnc" for adding the extras to this post after he made his post.
Bruce
http://www.facebook.com/album.php?aid=9526&id=100001809171788&l=5ca2c69fc9
78 Eleganza II, more demanding of attention & the pocket book than the wife but less bitchy (my better 1/2 suggestion).
[Updated on: Sun, 07 November 2010 20:20] Report message to a moderator |
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| Re: small fridge question 3 amps? Really [message #105399 is a reply to message #105371] |
Sun, 07 November 2010 19:28 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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Senior Member |
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OK, it looks like all the numbers on power consumption pretty much line up.
Forget about the amps for a 120 VAC house fridge through an inverter. They are just not about efficiency.
But the bdub article said 8 amps for a big Nocold with a DC compressor so 3.2 amps for the little Danfoss fridge sounds about right.
As for solar, assuming a 50% duty cycle and assuming close to 50% sunshine on a summer day, then a 25 or 30 watt solar panal would recover most of the daily battery loss, not counting other 12 volt usage.
As for relocating the AC- The revcon happens to have a fairly large fridge vent high up on the side of the coach. along with a vent on the roof. I think a large window unit could fit nicely indside that box (if i go wit ha smaller fridge) and I think small 12 volt fan (like a cooling fan from a small car) would move ethe air out sufficiently.
If it works it would be kinda' cool- clean roof line, much cheaper AC, and if the AC croaks on a trip i can just replace it at walmart.
And, if it doesn't work, it's not a permenant change.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] small fridge question 3 amps? Really [message #105410 is a reply to message #105352] |
Sun, 07 November 2010 20:44 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
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Senior Member |
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That's one heckuva price for the Tundra. I had a
Tundra 8 cubic footer on my boat that developed
a refrigerant leak. I had paid over $1500 for it
when I bought it in 2002. That's about what I had
to pay for the new Vitrfrigo to replace it. Actuall,
I'm pretty sure that Tundras were the rebranded
Vitrifrigo (made in Italy) fridges. They do use a
Danfoss compressor that works on either 12 or
24 Volt (nominal) DC. The 8 cu ft models use
just about 4 Amps when running on 12V and
about 1.8 Amps on 24V. To run on 120 (or 240)
V AC, they use an electronic, fan-cooled power
supply to get 24V from "shore" power.
They are VERY well insulated, and run maybe
10-15% of the time, so total current draw is low.
You can't go wrong, especially at that price!
BTW, I hauled my "leaky" Tundra home from the
lake, and finally found a technician to take
a look at it last week. We found the leak and
the total cost to repair it will be just $125.
If nothing else, I now have a garage fridge for
beer and other stuff that will also work on DC
and could use it to replace the fridge in "Money
Pit" if the fridge in it turns out to be dead!
* * * * * * * * * * * *
* D C "Mac" Macdonald *
* Amateur Radio K2GKK *
* USAF & FAA, Retired *
** Oklahoma City, OK **
* * * "Money Pit" * * *
* * ex-Palm Beach, 76 *
* * * * * * * * * * * *
* "An unarmed man can but flee *
* from evil. Evil can NEVER be *
* overcome by flight FROM it." *
> To: gmclist@temp.gmcnet.org
> From: david.j.silva@uscg.mil
> Date: Sun, 7 Nov 2010 12:47:07 -0600
> Subject: [GMCnet] small fridge question 3 amps? Really
>
>
>
> The revcon currently has regular dorm fridge. I recently acquired a Dometic two way (LP & AC) which i plan to install over the winter.
>
> But yesterday in a pawn shop i found 12V tundra mini fridge. It looked brand new. The pawm shop must have thought it was an ordinary dorm fridge- i snatched it up for $49.
>
> The paperwork says the mini fridge draws 3.2 amps at 12V
>
> All this as a domino affect on interior design strategies;
>
> If i could live with the mini fridge I could sustain the power with a 25 watt solar panel.
>
> And i could put a home window AC unit in the vented refrigerator space and clean up the roof line.
>
> A little unconventional- but......
>
> --
> Dave & Ellen Silva
>
>
> Happy owners of a 1972 Flatnose Revcon
> Here by the generosity of the GMC community
> http://www.davesilva.com/revcon
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| Re: small fridge question 3 amps? Really [message #105411 is a reply to message #105399] |
Sun, 07 November 2010 20:50 |
 |
WD0AFQ
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
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Senior Member |
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Dave, even at 50% run time a 30 watt panel will not keep your battery up. 3 amp draw times 12 hours{50%}, that is 36 amphours.
It just won't work. Get a 125 watter.
Dan
3 In Stainless Exhaust Headers
One Ton All Discs/Reaction Arm
355 FD/Quad Bag/Alum Radiator Manny Tran/New eng.
Holley EFI/10 Tire Air Monitoring System
Solarized Coach/Upgraded Windows
Satelite TV/On Demand Hot Water/3Way Refer
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