Question on 12 volt refer (updated with some answers)

[Jeffmo63]

After doing the math many times I've concluded that I can not run a 115 volt refer from a 12v to 115vac inverter for more than a few days until my battery bank is depleted. Even supplemental solar charging doesn't seem to help that much. A quick check on 12 volt refers shows they have a relatively low current draw (< 5 amps). Unfortunately, price is inversely proportional to current demmands (> $750). Does anyone have any experience with 12 v refers and does the cost justify the convenience? Any commments would be apptreciated.

[Ageless]

Running any 100V devise off an inverter for more than a brief period is not wise; the inverter itself consumes amps.

Bite the bullet and buy a unit made for RV usage. Mine runs several days on a deep cycle 12V without draining the battery.

Check around; there are rebuilders that sell refurbished units at a much lower cost.

[AZSpyder]

I have a used E-bay special Norcold DE-451 for a trailer I have been working on for a while. It was advertised at 3.1 amps but measurements were closer to 3.8-4 when running. During a run test at 70 degree room temperature it ran for 21 minutes over a hours timing. For that test it was averaging around 1.3 amps per hour. Of course this will vary with ambient temperature, what is in it and how often you open the door to see if anything good has appeared (like I do at home).

I sure like the price of the small refrigerators at the big box stores. I also started out looking at inverters. One thing not mentioned is you may need a high end inverter with a true sine wave output to run the compressor. As you noticed there is a lot of current required with the efficiency loss of converting one type voltage/current to another.

I have just a few DC light to run besides the refrigerator. I figure I'm going to need a Group 27 battery for maybe two nights and one day off the grid. I still need to get a 80 watt or bigger solar panel for anything longer. At least I can charge for the tow vehicle and I expect many of our outings will involve hook ups and shower facilities.

Jerry

P.S. (After more thought)

I ran into some Internet hits about refrigerators running between 15 to 20 minuets in an hours time. My test showed this was in the neighbor hood for my Norcold but maybe I can expect more like 15 to 30 minutes. Longer running during the day when the temperature is up (and solar panels are up too) with the run time shortening during the night. It is hard to give a very accurate prediction for trip planning but it is a ballpark to work with.

The refrigerators current rating is the draw when running. You should be able to take the rated current times .25 to .50 for an hours draw. The "should" part is from finding my Norcolds rating was optimistic by 1/3. A good amp meter can tell you what it really is.

[astrotrailer]

I bought an Engel 45 quart recently and I am very happy with it.
It can act as a fridge or a freezer. I recommend buying a thermometer
with a external probe so you can monitor the temp from the outside.
The first night I turned it on I set it to a middle range and my beer was
frozen by the middle of the evening. Setting of 1 or 2 is fridge below that
is freezer down to hard ice cream. If you need to have ice you can use the
Engel act as a freezer to keep the longer stuff frozen and rotate a few frozen
half gallon water bottle to a small cooler and the Engel to keep other stuff
cool but not frozen. It draws about 2.7 amps when the compressor is running
but cycles on and off as needed so the hourly draw is much less. I have
a 160 watts of solar on the roof so I have plenty of recharge capacity for
my 130 amp hour battery when the sun is shining. We got it for $729
shipped. I am going to 3 astronomy star parties this summer and it will
get a lot of use. Hopefully it lasts a long time.

[greekspeedoman]

I have a friend who uses an Engel 45 as well. it is a great little thing. It can run about 4 days on a battery.

I am looking at a less expensive option that uses the same compressor that Engel has. It is an Edgestar. I have another friend who just bought one & so far he is pleased. He also camps with us and has used the Engel.

I have links and stuff for it here: http://www.overlandtrailer.com/2010/05/04/working-the-galley/

[Engineer Guy]

We've already got a monsterous Igloo 5 day Cooler w/Hose pipe thread for draining melted ice water. I'm thinking of putting it under a lift-up, hinged Countertop in the future CT build. The cabinet it's in would be lined with high R value Thermax rigid foam and/or Astrofoil, increasing the R value even more and decreasing thermal loss. As with home chest-style Freezers, this horizontal Cooler idea would minimize cool air loss when opened. I would connect the Countertop to the Cooler lid so it opens in one movement. We recycle double seal Zip Lok bags ~3/4ths full of water to make ice.

We may make our own ice periodically to add to this Igloo, but this would require a +12 VDC Freezer of some type [see below]. Not a bad thing, because then we would have Freezer capability w/o the steep price of a full blown RV Fridge/Freezer [which I've also used]. ~Biweekly use of a Freezer only to make ice would minimize Battery or Solar Panel current consumption when off-Grid. An alternative idea would be to retrofit an appropriately-sized Thermoelectric 'Peltier' Module to the Igloo, or spring for a new, smaller Koolatron Cooler below.

From having a Thermoelectric Cooler with modest insulation already, I understand Thermoelectric limitations. The el cheapo one I have now worked fine while building a House. Thermoelectric Module Controllers are available to vary the cooling rate of the Module, and thus acting like a Thermostat.

http://www.pronto.com/user/search.do?di ... 4998&site=

http://koolatrononline.stores.yahoo.net ... rmers.html

http://www.igloocoolers.com/Thermoelect ... Cool-Chill

http://www.survivalunlimited.com/refrigerator.htm

[Karl]

...

[NathanL]

This will sound really dumb but how long do you need stuff to stay cool? I get buy with an outfitter quality ice chest and it will keep ice frozen for up to 7 days in TX heat if kept in the shade or inside the trailer, but I don't constantly open and close it either.

[len19070]

This will sound really dumb but how long do you need stuff to stay cool? I get buy with an outfitter quality ice chest and it will keep ice frozen for up to 7 days in TX heat if kept in the shade or inside the trailer, but I don't constantly open and close it either.

I'm with you Nathan...

How Long do you need it cold for?

I have and use a couple of 35+ year old Coleman Stand up coolers.



It keeps Ice and food cold for 6 days using Block Ice.

Can't find Block Ice?

I make my own freezing 4 recycled pretzel containers.



Personally I think that getting a Refrigerator. and getting a battery and an inverter and a charger and hooking it up and spending a good weeks Pay on all of it just to emulate ICE.

Is lowering the River instead of raising the Bridge.

There are a lot of Really Good Coolers out there nowadays. In almost every Price range.

As far as the dripping wet food from the Ice melting.....I can't believe that I still hear that complaint.

If you can do all the computations on how many Jigga-watts can go through a Flux Capacitor through 10 gauge wire with a 30 amp fuse at sea level in both the Atlantic AND Pacific at Noon on an equinox AND know the exact discharge rate...or have a discharge rate scale available so it can be computated accurately to hour and Minuit Greenwich England time for any Battery ever manufactured at any time on the Planet.

But not be able to figure out that by freezing water in a Plastic container will eliminate water in the bottom of a cooler.....

Then I understand why there is a need for Velcro Shoes.

3 simple words.

Frozen Milk Container, or Frozen Juice Container, or Frozen Plastic Container.

That word "Container" The Root Word is Contain.

Its almost like complexity is part of the "Fun" of it all for some.

Happy Trails

Len

[8ball_99]

We bought a couple of those 5 day colman coolers awhile back.. Tried them out this past weekend.. I have to agree with the above post.. I think you guys are making something simple and cheap complex and expensive.. I'm sure some really need a fridge. But if you just want to keep your stuff cold for a few days just fill some large plastic bottles with water.. Freeze them and tada.. After 3 days our 2 Ice bottles were still 85% frozen. Everything was ice cold. We carry two coolers.. One for food and one for Drinks. The one with food has NP at all staying cold cause your only in it a few times a day.. We still just use Ice in the drink cooler cause the water/ice mix cools hot drinks down very fast.. Just might have to add ice every other day or so..

[NathanL]

Another tip for camping and a cooler. If you have a regular igloo/coleman type cooler and want the ice to last longer put a piece of 2" sheet insulation in the floor before you put in your food and ice and it will help a lot.

I have an outfitter model that's similar to a Yeti cooler and the wall thickness is about 4" and the top is sealed with an O ring.

[Gonefishin]

As far as the dripping wet food from the Ice melting.....I can't believe that I still hear that complaint.

If you can do all the computations on how many Jigga-watts can go through a Flux Capacitor through 10 gauge wire with a 30 amp fuse at sea level in both the Atlantic AND Pacific at Noon on an equinox AND know the exact discharge rate...or have a discharge rate scale available so it can be computated accurately to hour and Minuit Greenwich England time for any Battery ever manufactured at any time on the Planet.

But not be able to figure out that by freezing water in a Plastic container will eliminate water in the bottom of a cooler.....

Then I understand why there is a need for Velcro Shoes.

3 simple words.

Frozen Milk Container, or Frozen Juice Container, or Frozen Plastic Container.

That word "Container" The Root Word is Contain.

Its almost like complexity is part of the "Fun" of it all for some.

Happy Trails

Len

That's just beautiful Len!! Eloquently spoken!!!

And yes, I have a couple of Coleman Extreme coolers I use both camping and on other long-range trips, and they keep ice solid for days, whether inside a container (preferred) or out. Saltwater Sportsman did an actual test with these and some higher-priced Yettis and other premium coolers, and the Coleman Extreme won!!!

[AZSpyder]

I expect that many don't realize that jigga watt and flux capacitors don't actually exist. These were made up for Hollywood movies and really need not be worried about in keeping food cold. Sea level is actually only slightly involved with a minor effect for air density but you really don't need to go that far. The electrical loading is actually straight forward but yes it does take a bit more thought then understanding how to make ice.

It is good to know that there are iceboxes that will work of days. How many work for weeks, how many more work for months. Can you get frozen pretzel containers at the local mini mart? The last time I was at my favorite camp ground in nowhere Nevada there were no pretzel containers available. In fact, there was no ice in site but there was plenty of sun for the solar panels. Besides wanting to run for 2 to 3 weeks at a time I didn't like much of the small space available being taken up with blocks of ice. I would rather use the space for food storage. There are plenty of threads on iceboxes but this member was asking about refrigerator loads.

Jerry

[len19070]

I expect that many don't realize that jigga watt and flux capacitors don't actually exist. These were made up for Hollywood movies and really need not be worried about in keeping food cold. Sea level is actually only slightly involved with a minor effect for air density but you really don't need to go that far. The electrical loading is actually straight forward but yes it does take a bit more thought then understanding how to make ice.

WOW, I did not know that.

I'm gettin outa this....this stuff is just to smart for me.

Once ya get the cold thing straightened out, I'll explane Humor to ya.

See there was this Chicken................................................

[Engineer Guy]

For those of us practicing or contemplating long stays off-grid, Solar-based Fridge cooling options are the deal.

Since the Sundanzer or Sunfrost Fridges - Sunfrost being the fav of off-grid folks for Home - are not necessarily designed to withstand road rigors, the Engel or Edgestar Fridge/Freezers sound pretty sweet. The real world testimonials above are duly noted - especially at such a great price - since a PV Panel-based scenario is identical to our intended use.

The 3 way Fridge in my '83 Avion used on site while building a Solar House sprung a leak in the Ammonia tubing. I got a slight whiff of those fumes, and innocently opened the full size Fridge while investigating. The blast of accumulated Ammonia on a warm day choked and knocked me down. I'm damned lucky I wasn't blinded. Lesson learned, not to the mention the hassle of having to level those Fridges, and their cost.

Thick wall superinsulation helps any cooling method, and is a key part of the 'home' Fridges linked below. Energy you never lose you never have to replace.

For about the same amperage draw as a Fantastic Fan, I plan to use the 'Swamp' Cooler linked here to keep the CT at modest temps whether we're in it or not. CT water will be supplied out of Truck bed Tank that enables long term BLM Land camping, etc.

http://www.turbokool.com/

At ~70 F degrees internal CT temp, Thermoelectric Coolers that drop the internal Fridge temp by ~40 F degrees become an option. A PV Solar-based 'plus' is their low current draw, although an efficient Compressor Fridge doesn't draw much either. Since we have lotsa spare Insulation laying about, and a 5 day Cooler and a Thermoelectric Cooler already, we'll experiment first. We'll spend more $$ later for the Engel/Edgestar if req'd. It appears the amperage draw for all these cooling solutions is about the same.

As the old saying goes, 'a teaspoon of honey attracts more flies than a gallon of vinegar'. With this maxim in mind, I'll let my babe of a Wife hit up some friendly Big Rig RV'ers nearby to make a water-filled Ziploc bag or two of ice in their full-featured Fridges for our use in a 5 day Cooler, or in a Thermoelectric Cooler if the clouds set in long term. A guy's gotta have a backup plan, and we seem to make friends in any Country we've visited... Besides, my beloved 'Snyders' Pretzels come in a box that's no good for holding ice. ;-)

Running the connected TV for ~1/2 hour to charge CT Batteries is another 'last ditch' way to recharge DC. As PV Panel prices/watt continue to drop, a couple of Panels on my CT roof will likely keep us powered just fine while skipping Generator cost + noise.

The Engel ~2.7 Amp current draw kindly supplied above equals ~38 watts @ an assumed 14 VDC. I guess we got off-grid Food preservation under control. Now, if only I can get around powering The Wife's 115 VAC Hairdryer with a pricy Inverter or Honda Generator, I'll have the +12 VDC life all covered!

http://home.howstuffworks.com/solar-pow ... rator1.htm

http://www.sunfrost.com/refrigerators_main.html

http://www.google.com/search?aq=0&oq=en ... frigerator

http://www.google.com/search?aq=f&sourc ... star+FP860

http://en.wikipedia.org/wiki/Watt