Igloo Kool-Mate 40 Discussion
Franklin Jennings
[This is x-posted to all the newsgroups I could think of with the
knowledge base and possible interest in the topic. If you are
uncomfortable, trim the headers, as I read all these groups for info.]
Today, while cruising through Sears, I saw one Igloo Kool-Mate sitting
on the shelf. (I was getting a couple of lightweight rod and reel
combos, Zebco 202s, for a Crappie trip next weekend with the [commonlaw]
wife.) Anyway, I got it on sale for about $50.00 and took it to the
car. Plugged it in, and drove 40 miles total running it empty. It had
cooled completely by the time we got home. I must say I was pleased.
But ever looking for as much efficiency as possible, I have some
questions.
I got the thing for a remote cabin we have for weekend getaways. (I
grew up on a dirt farm in 'Bama, so Atlanta gets me batty!) Anyway, we
are going solar out there, and refrigeration was a concern. After
looking at all the hi-efficiency fridges, and gas models, I figured this
would be a real good compromise. Now, we only store drinks, and a stick
of butter we bring with us, and maybe some cheese or steaks or such, for
the weekend. We keep the reefer we have now off during the week, empty,
since we aren't there.
Now, I was figuring I could hot glue styrofoam sheets to the outside of
the cooler, excepting the area where the vents, fan and power cord are,
of course. The only problem with it I can find is that it is a
continuous use heat pump, with no auto shut off. According to the spec
sheet, she uses 4.5 amps @ 12Vdc. Now that ain't bad, I would think,
but it could be better.
Now, I have a few other ideas to bounce, let me know what ya'll think.
Adding a digital thermometer to the inside, with the readout on the
door. Anyone know if I can wire the thermometer to a relay, so that it
will shut on and off automatically when the temp. reaches a cutoff and
cut-on point? I figure the mods aren't that difficult to make,
especially if the thermometer has an alarm for a high and low temp. Run
the alarm wires to a relay switching power to the reefer on and off.
All around, how's it sound? And has anyone played with these before?
--
"Government is not reason. Government is not eloquence. It is force.
And, like fire, it is a dangerous servant and a fearful master."
---George Washington
"In matters of conscience, the law of majority has no place." -Mohandas
Gandhi
"If you will not fight for right when you can easily win without
bloodshed; if you will
not fight when your victory will be sure and not too costly; you may
come to the moment
when you will have to fight with all odds against you and only a
precarious chance of
survival. There may be even a worse fate. You may have to fight when
there is no hope
of victory, because it is better to perish than to live as slaves." --
Winston Churchill
on the eve of Britain's entry into World War II
cjvdm
Yes of course, I purchased mine with the automatic temperature control
built in, several companies supply them that way and also as food
warmers. Which only requires reversing the polarity to the
thermoelectric module.
If you real want to be efficient do not glue anything to it. Instead
build a air tight insulation box to place it in, with a two hinged
doors. One to get food and the other to allow air flow when you are
operating it (absolutely necessary or it will over heat and be
destroyed. When it is cold enough turn it off and close the door it
will stay cold for a day if you don't open it. Never palace warm food
in it if possible. It takes more than a day to completely cool a full
cooler with warm food. If you don't shut of the air flow it will warn
up the external heat sink then the thermoelectric module and then the
heat sink inside and eventually the contents. These coolers are
designed to keep things cold and have limited cooling power only about
50 degrees below the outside air cooling the heat sink. You can get
them to freeze the contents if it is cool enough at night or place ice
or snow near the air cooling it.
DC
cool little 12VDC cooler, and you beat me to it. Oh well, I haven't used it
yet, but I think it will come in very handy on road trips, camping, and Y2K
(if needed). I'm in the process of getting everything I need for power
outages to run off 12VDC. Now that I have this cooler, I can load most of
what I need from the frig into it when I decide to stop powering the frig
using the gasoline generator.
Great write up on it, saves me some time talking about it. I'm going to look
into a thermometer like you are.
DC
Franklin Jennings wrote:
Franklin Jennings
Ok, I was sitting here about five hours after my last post when it hit me: Why not just have a temperature actuated relay, or some other temperature controlling on/off circuitry.
Did a websearch and found this page: Dwyer's Instruments Inc.
Fired off an email to their tech guys at mailto:te...@dwyer-inst.com
asking for their recommendation for switching a 12Vdc/5Amp ckt off at <40F
and on at >45F. I will post back with their response when I get it.
wombat
>On Sat, 20 Mar 1999 22:00:05 GMT, Franklin Jennings
1==> 4.5 amps at 12 volts is 4.5 * 12 = 54 watts, which is a fairly
heavy drain. Those contemplating a similar small fridge might want
one that operates off propane gas instead....not that propane will
always be available either.
>>Now, I have a few other ideas to bounce, let me know what ya'll think.
>>
>>Adding a digital thermometer to the inside, with the readout on the
>>door.
2==> Sure, this is easy. A few months ago I picked up one made in
China for a local firm. Liquid crystal display, switchable
indoor/outdoor [comes with 3 meters of cord and external probe],
switchable centigrade/ fahrenheit. Range plus or minus 50 C, which is
minus 58 F to plus 122 F. Display is about 12 mm [ 1/2 inch] high.
Constantly on, as circuit uses so little power that get the life of
the battery out of it anyway. Say about two years if don't keep
pressing the backlight display button to light up the display.
From memory, was about $A 12 which would be about US$ 7.80.
Check your local Radio Shack or other electronics store.
> Anyone know if I can wire the thermometer to a relay, so that it
>>will shut on and off automatically when the temp. reaches a cutoff and
>>cut-on point? I figure the mods aren't that difficult to make,
>>especially if the thermometer has an alarm for a high and low temp. Run
>>the alarm wires to a relay switching power to the reefer on and off.
>>
3==> Have seen similar units to the one I've described which to have a
settable alarm for high or low temperature, might be slightly more
expensive, but not much.
4==> Setting up an "automatic" controller is a bit more of a problem.
For one thing, if you use a relay to switch the current, the relay
coil itself consumes power. There are ways to get around the use of
a relay using solid state switching, but the next problem is providing
a "dead band".
5==> To explain this, assume you devise a circuit that switches the
unit on when the temperature rises to 34 deg F. Fine, easy enough to
have a control unit do that. Problem is, though, that the unit starts
operating at 34 F. A few seconds later, the temp drops just below 34
F., so it shuts off....so it is continually switching off and on
around that 34 deg set point, which not only wastes power, but could
eventually cause problems.
In a room thermostat, if had something like this the furnace [or
whatever] would be continually cycling. So a conventional thermostat
set at say, 68 F, actually doesn't turn on until the temperature drops
to perhaps 64 F and doesn't shut off until it rises to, say, 72 F. So
with your fridge, would want something that perhaps switches on at
36 and off at 32.
6==> Possibly the easiest way to accomplish this is to salvage an
old thermostat off a junked refrigerator and use that in conjunction
with a relay of some sort. [ The contacts on the old fridge relay
may switch an amp or two at 120 volt AC, but that doesn't mean they
will handle 4.5 amps at 12 V DC very long without burning out.
7==> The easiest solution, of course, is to find a way to get by
without refrigeration.
~ larryn
>>All around, how's it sound? And has anyone played with these before?
Banklash
>for
>their recommendation for switching a 12Vdc/5Amp ckt off at <40F and on at
>>45F.
I think you'll find their price much more than the cost of your cooler. What
they sell is heavy duty industrial stuff, not consumer grade.
George Conklin
cjvdm <CJ...@CRIS.COM> wrote:
And has anyone played with these before?
>Yes of course, I purchased mine with the automatic temperature control
>built in, several companies supply them that way and also as food
>warmers. Which only requires reversing the polarity to the
>thermoelectric module.
>
I have had several such units. What gives out are the
fans. Unless you get the trucker model with a
high-reliability fan, the fan will fail in a couple of
months and you will need to get yourself ball bearing fan
like from Radio Shack and modify the baffle to take it. We
had a model from Germany and I spent a lot of time looking
for the right model. One day the fan failed suddenly and
the unit 'burned up', i.e. the junctions disconnected. They
cost about $30 each, if you can find them, so that means
getting another unit. Were I you, I'd go in for a small gas
refrigerator from an old travel trailer.
Nat Kimble
> cjvdm <CJ...@CRIS.COM> wrote:
>
> And has anyone played with these before?
> >Yes of course, I purchased mine with the automatic temperature
> control
> >built in, several companies supply them that way and also as food
> >warmers. Which only requires reversing the polarity to the
> >thermoelectric module.
Is this DC cooler based on the Peltier effect? If so, they are
convenient
because they are almost solid state (minus the fan) but they are
supposedly
inefficient as all hell...
You can see a good description of how simply they work at...
http://www.americool.com/basics.htm
and then
http://www.americool.com/moduleworking.htm
And you can see why simple polarity switching changes the cooler to
a heater... thus it is often used for laboratory devices that have to
keep
something at temp X with only 1 degree variance,
-- Nat Kimble
Franklin Jennings
George Conklin wrote:
> In article <370a2f99...@news.concentric.net>,
> cjvdm <CJ...@CRIS.COM> wrote:
>
> And has anyone played with these before?
> >Yes of course, I purchased mine with the automatic temperature control
> >built in, several companies supply them that way and also as food
> >warmers. Which only requires reversing the polarity to the
> >thermoelectric module.
> >
>
> I have had several such units. What gives out are the
> fans. Unless you get the trucker model with a
> high-reliability fan, the fan will fail in a couple of
> months and you will need to get yourself ball bearing fan
> like from Radio Shack and modify the baffle to take it. We
> had a model from Germany and I spent a lot of time looking
> for the right model. One day the fan failed suddenly and
> the unit 'burned up', i.e. the junctions disconnected. They
> cost about $30 each, if you can find them, so that means
> getting another unit. Were I you, I'd go in for a small gas
> refrigerator from an old travel trailer.
Igloo sells all the parts for the cooler, including the PC board and
Peltier unit. Am thinking about buying replacements for the peltier and
the fan and the board, just to keep onhand.
Dusty G.
wiring within 10 hours of use. I contacted Igloo, and they were very
rude, and refused to do anything, even though it was still in warrenty.
From what I understand, that is their 'normal' way of doing business.
We'll not buy anything made by Igloo again.
Dusty
George Conklin
You fan probably shorted out. Once that happens, it is
all over. The models sold in truck stops have long-life
fans, and you pay a little extra for that. Otherwise, about
10 hours on a fan motor is not unhead of. I have had some
fail in that length of time. If they do fail, and you don't
pull the plug, everything does start to melt. I have had
that happen with a Gemman model I really liked, but I spent
a lot of time looking for fan motors too. One failed while
I was at work and the leads to the junctions melted and that
was the end of that cooler.
Raymond Leistner
> You fan probably shorted out. Once that happens, it is
> a lot of time looking for fan motors too. One failed while
> I was at work and the leads to the junctions melted and that
> was the end of that cooler.
put a thermal fuse in series with the power supply. clip the fuse
to the heat sink. If heat sink heats up too much, fuse will open and
save the module.
George Conklin
The cooler under consideration really did not have room
for that. Further, you would need to experiment to get the
right values, and guess, what, you would burn out junctions
experimenting. But the person who posted that his cooler
'burned up' in 10 hours is not unique in that problem.
Those coolers, regardless of who sells them, are very
fragile and have no safety fallbacks. Most seem to have
been designed for easy of production, not use, and function
quite poorly. I took my Kooltron and had to modify it
extensively to use a Radio Shack fan with ball bearings and
extended life. Nevertheless, it is probably still a fire
risk you would want to think about if using a 120-volt
adaptor. I think the 'trucker model' sold at truck stops
may well be better since they advertise extended life.
Extended from 10 hours at any case, but how long I don't
know.
Franklin Jennings
Igloo send replacement parts for two different items I have had over
time. The earlier poster was quite wrong when he said rudeness was
business as usual for those folks. As always, YMMV ;)
George Conklin wrote:
--
Q
regular junk refrigerator and put it in the power circuit.
For efficiency, you'd be much better off getting one of those little 1.7
cubic foot 110VAC refrigerators and running it off a 250 watt inverter.
Q
> >Now, I have a few other ideas to bounce, let me know what ya'll think.
> >
> >Adding a digital thermometer to the inside, with the readout on the
> >door. Anyone know if I can wire the thermometer to a relay, so that it
> >will shut on and off automatically when the temp. reaches a cutoff and
> >cut-on point? I figure the mods aren't that difficult to make,
> >especially if the thermometer has an alarm for a high and low temp. Run
> >the alarm wires to a relay switching power to the reefer on and off.
> >
> >All around, how's it sound? And has anyone played with these before?
> Yes of course, I purchased mine with the automatic temperature control
> built in, several companies supply them that way and also as food
> warmers. Which only requires reversing the polarity to the
> thermoelectric module.
>
> If you real want to be efficient do not glue anything to it. Instead
> build a air tight insulation box to place it in, with a two hinged
> doors. One to get food and the other to allow air flow when you are
> operating it (absolutely necessary or it will over heat and be
> destroyed. When it is cold enough turn it off and close the door it
> will stay cold for a day if you don't open it. Never palace warm food
> in it if possible. It takes more than a day to completely cool a full
> cooler with warm food. If you don't shut of the air flow it will warn
> up the external heat sink then the thermoelectric module and then the
> heat sink inside and eventually the contents. These coolers are
> designed to keep things cold and have limited cooling power only about
> 50 degrees below the outside air cooling the heat sink. You can get
> them to freeze the contents if it is cool enough at night or place ice
> or snow near the air cooling it.
--
---------------------------------------
POWERCHUTES.COM
http://www.powerchutes.com
---------------------------------------
Phelix Bruner
George Conklin wrote in message <7dbteq$psf$1...@nina.pagesz.net>...
> I think the 'trucker model' sold at truck stops
>may well be better since they advertise extended life.
>Extended from 10 hours at any case, but how long I don't
>know.
I drove a big rig for New Prime Inc. out of Springfield, MO. for a while and
during three months of constant 24 hour a day running my partners cooler
never had a problem. I don't recall the brand name but he paid 89.95 for it
at a truck stop and it came pre-wired for 110 volts (we had a built in
invertor, in the truck). We used it as a small refridgerator, but we had to
be careful not to accidentally freeze items.
Shep
inverter as well as the KoolMate and these are the results I found:
The 80W refer worked much better as far as making ice and keeping things
cold. It ran on my batteries for27 hours before the inverter shut down at
10Volts.
however -
The Koolmate continued to run for several hours longer because I allowed it
to stay connected until the batteries discharged to 5 volts. It does not
make ice but, if kept out of the sun will keep a drink cool (not icey cold).
conclusion - I will keep the little fridge! The Koolmate I will keep around
for use if the little fridge ever goes kaput.
Shep
PS I also have a free conversion of a small B&S genset to propane. Will
tell my secret to anyone who e-mails me and asks for it. I converted my 3.5
horse for free, no gadgets or carb needed!
Q wrote in message <36FEF505...@POWERCHUTES.COM>...
Adam DePrince
Don't take deep-cycle lead acid batteries down that far. Once you get
to 10.5 volts on a 12V battery stop. Cared for a deep cycle lead acid
battery will give you 400-600 cycles. The "cutoff" feature of the
inverter is a feature, not a bug. Drop below 10.8V and you will be
lucky if you lose only 1/2 of its capacity and get 10 more cycles out of
it.
BTW, don't use plain starting batteries for this type of work, normal
starting batteries are great for short, heavy loads, but if you use more
than 5-10% of their capacity you rapidly diminish their lifespan.
--
Adam DePrince - depr...@sprynet.com
ro...@mauve.demon.co.uk
: As far as temperature control goes, just get a thermostat out of a
: regular junk refrigerator and put it in the power circuit.
: For efficiency, you'd be much better off getting one of those little 1.7
: cubic foot 110VAC refrigerators and running it off a 250 watt inverter.
This causes thermal fatigue, on the peltier device.
If you do this, put a resistor in paralell with the switch, so that it
allows around half the rated current to flow. (Don't forget to connect
the fan to the supply before the resisitor.
sha...@prolog.net
you need to read about peltier junction coolers. there is a limit to how
cold they will get your igloo coolmate. it is possible to hook them up in
series and get an actual really cool refrigerator or freezer, but you are
better off getting a small refrigerator instead if you are going to do that.
your concerns about putting a thermostat on it to shut it off when it gets
cold are not really a problem. the thing will never get that cold that you
will want it to shut off unless the ambient temp is kind of cool to begin
with. check out the manual that came with it....it gives a list of the
ABSOLUTE coolest the inside will get depending on the ambient temperature.
its a usefull toy, and i have camped with one for years, but quite frankly i
gave up and just bought dry ice when i was going to be out for more than
three days at at a time, and regular ice for periods less than that.
i KNOW it violates the principle of making an alternative source of
refrigeration to do that. if you are REALLY interrested in a peltier cooler
refrigerator, i suggest you do a web search, or better yet, go to the nearest
magazine store, and buy a copy of the magazine "nuts and voltz" in their
advertizement section (the whole thing is basically advertizements) they have
peltier cooler assemblies for sale cheap. you can make your own refrigerator
out of them easier than modifying the coleman coolmate.
i did the above and had better success with it than the coolmate. but i was
only playin around and i took the junctions apart to use them for cooling the
chips in my computer (thats why nutz and voltz sells them) so that i could
overclock it. (pentium 200 running at 400 mhz....hehe)
shadow laughs.
the space shuttle uses peltier junction coolers for its perishable items. i
am not sure what set up they have but i do know that it isnt cold enough to
actually freeze anything. i believe that to do that, from what i was looking
at, in any reasonablly speedy time frame, you would need, get this:
someplace around 11 or more peltier junctions cooling in series....three then
two then one, of course you could do it in other ways, but it certainly isnt
efficient if you are planning on using a lot of food from the frige
quickly....i still like the idea but it isnt a panacea.