Making a 12V Cooler

[woytovich]

I have no DC electrical system in my trailer plan. Only AC.

Then why not a small "dorm" fridge? You could tear it apart and reformat it for your custom space.

$69 on sale

http://www.target.com/Emerson-1-8-Cu-Compact-Refrigerator/dp/B0039S88XQ/ref=sr_1_1?ie=UTF8&searchView=grid5&keywords=Emerson%201.8&fromGsearch=true&sr=1-1&qid=1308005545&rh=&searchRank=target104545&id=Emerson%201%208%20Cu%20Compact%20Refrigerator&node=1038576|1287991011&searchSize=30&searchPage=1&searchNodeID=1038576|1287991011&searchBinNameList=subjectbin%2Cprice%2Ctarget_com_primary_color-bin%2Ctarget_com_size-bin%2Ctarget_com_brand-bin&frombrowse=0

[mikeschn]

I read the linked comments and it relates negative in ways that do not apply to me. I am not using it in temps over 80 degrees. I am not concerned about bringing food home. I am not concerned so much about food in general really. But I understand the negatives and that is why I will experiement with a cheap used unit first. I was also thinking I could strip the components from the used unit and instal them in a super insulated unit I would make.

I'm glad you understand. We are not picking on your ideas, only disseminating information on why it didn't work for us. Keep posting your thoughts and results, we'd love to see how you make it work!

Mike...

[StandUpGuy]

I did not take any comments in a negative way. Don't worry.

I purchased the DC cooler in a hot parking lot in Charlotte North Carolina. It was about 91 degrees outside. The unit came from a hot trunk of an old Buick. I bought it for $15 figuring I need a center consol between my vans bucket seats anyway..cold or no cold. I plugged it and drove home the twenty two minutes. Very little happened in the way of cooling. I put my hand on the heat sink inside the box and it got cold. If I was drinking a beer the temperature of that metal I would be happy. But the box itself did not do a lot of cooling down on the drive home. There is something I do not understand about the unit. There is a fan that blows air from the outside and across the heatsink and into the cooler. Right way I think this is not a good arrangement. Heck on the outside vent of the unit it was hot on one side and the other side of the vent it was cold. Actually cooling of the exterior of the unit. That is a big waste. This arrangment does not look the same as the method used on the instructions I found for building a cooler.

[StandUpGuy]

I have no DC electrical system in my trailer plan. Only AC.

Then why not a small "dorm" fridge? You could tear it apart and reformat it for your custom space.

$69 on sale

http://www.target.com/Emerson-1-8-Cu-Compact-Refrigerator/dp/B0039S88XQ/ref=sr_1_1?ie=UTF8&searchView=grid5&keywords=Emerson%201.8&fromGsearch=true&sr=1-1&qid=1308005545&rh=&searchRank=target104545&id=Emerson%201%208%20Cu%20Compact%20Refrigerator&node=1038576|1287991011&searchSize=30&searchPage=1&searchNodeID=1038576|1287991011&searchBinNameList=subjectbin%2Cprice%2Ctarget_com_primary_color-bin%2Ctarget_com_size-bin%2Ctarget_com_brand-bin&frombrowse=0

That is a good idea. I had not thought of that.

[notned]

Sometimes I ask questions that I don't want to hear the answer to also.

[StandUpGuy]

Sometimes I ask questions that I don't want to hear the answer to also.

Actually I would love to hear the negative response but have it be more like: "It cooled down to only 55 degrees and my potato salad went bad" Not just simply: It sucked". That does not tell me anything.

[StandUpGuy]

I took the cooling assembly apart and cleaned it up inside. The set up is an aluminum heat sink oustside with a fan to disipate the heat and an aluminum finned heat sink on the inside to cool. The motor that drives the fan on the outside also drive a smal turbin fan on the inside to attempt to distribute the cooled air within the cooler. That fan barely does anything, as the shroud around it does not fit with any sort of sense of containing the airflow. It is very open.In addition I think there is some air leaking from the inside to the outside from this double fan assembly. n a nut shell half of the cold are is blown outside. I took the partially disassembled cooler out to the van and ran it and without the shrouds around the fan on the inside it actually cooled off more. The shroud is blocking the cold metal "sink". I think it could be reworked to operate better. But I think a big part of it is making the "ice box" part of it smaller as the cooling assembly is not powerful enough for such a large box. It is my guess that this could be reworked to efficiently cool off a six pack of cans and no more.

[StandUpGuy]

When they say that these can only cool off relative to the ambient temperature, I am guessing that means the cooler the outside "heat sink" the cooler the inside one can be. If this is so then it is very important for the outside hot "heat sink" to be cooled by an efficient fan. I believe this allows the inside one to cool more. To that end I have another experiment in mind, that is to rig up a more powerful fan to the exterior heat sink and see what happens. To make this relatively scientific, I need to measure the general outside temperature and the specific inside cooler temperature, both with the rig as manufactured and then modified with the more powerful fan.

[Engineer Guy]

Well I think it will be an interesting thing to seperate the facts on these units.

Heartily agreed.

The already-invented Wheel I suspect you'll wind up reinventing is stated/known in TEC Manf. Spec Sheets. Shift to the Tech 'Esperanto' data of, say, BTU or temp changes under thermal conditions 'x' for various size TECs [or doubled-up TECs] to see how modest their capabilities are UNLESS you dabble in large and/or expensive arrays of them.

If you want to dabble, that's great! As Mike and others here have noted or inferred, TECs thus far have not held the proverbial Candle to efficient Compressors, as used in Engels, et al.

[StandUpGuy]

Well I think it will be an interesting thing to seperate the facts on these units.

Heartily agreed.

The already-invented Wheel I suspect you'll wind up reinventing is stated/known in TEC Manf. Spec Sheets. Shift to the Tech 'Esperanto' data of, say, BTU or temp changes under thermal conditions 'x' for various size TECs [or doubled-up TECs] to see how modest their capabilities are UNLESS you dabble in large and/or expensive arrays of them.

If you want to dabble, that's great! As Mike and others here have noted or inferred, TECs thus far have not held the proverbial Candle to efficient Compressors, as used in Engels, et al.

I understand, I think the only thing I would approach differently on this would be the box itself compared to the cheap plastic coolers. If you put on tray of ice cubes in a big poorly insulated cooer it will not cool the beverages well. Put that same tray of ice in a small well insulated cooler and the beverages will be ice cold and for a long time.

[woytovich]

http://www.instructables.com/id/How-to-Convert-a-mini-fridge-to-a-chest-refrigerat/

[StandUpGuy]

http://www.instructables.com/id/How-to-Convert-a-mini-fridge-to-a-chest-refrigerat/

Really it is a good idea to modify a mini fridge to fit my space. Ultimately this is what I will probably do. Your liked article is interesting, though they did not make the unit smaller they did do a fairly radical change to it. I guess what it is is that compressor refrigerator kind of scare me a little. Lots of opportunities to ruin it. maybe I can find a really cheap down and dirty used mini for like 20 bucks.

Anyway thanks for the suggestions.

[jss06]

I have a small thermoelectric 12v cooler that is big enough for a six pack. I have used it on long trips and it will cool down to below 40* when in an air conditioned car. It will actually form frost on the inside cooling plate after a while.

They do not cool down fast if the items are warm. Its best to start with cold items an it will work much better.

[StandUpGuy]

I have a small thermoelectric 12v cooler that is big enough for a six pack. I have used it on long trips and it will cool down to below 40* when in an air conditioned car. It will actually form frost on the inside cooling plate after a while.

They do not cool down fast if the items are warm. Its best to start with cold items an it will work much better.

Why that is impossible!

[BrwBier]

I would not be without my electric cooler. But as I have always said we do not travel in the summer, only spring and fall. It is cooler out then and if you don't watch the temp inside you can freeze things. We have parked for up to 5 hours at an attraction and left the cooler plugged in with no starting problem. If we would camp without 110v we can just put ice in the cooler, the same as any other ice chest. If you understand how they work then you will not have a problem with one. I also wish that people who say they are bad would explain what went wrong and what they were trying to do. Just saying they are bad and my bologna went bad, my battery went dead, my beer was warm is not helpfull to anyone.
Brwbier