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TruckFridge CF49- Notes and Installation Story
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Sodo
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PostPosted: Sun Jul 12, 2009 8:35 pm    Post subject: TruckFridge CF49- Notes and Installation Story Reply with quote

Just got my Truckfridge CF49 by indelB. Seems discussion of specific operation of the CF49 doesn't belong in a thread showing installations ---> http://www.thesamba.com/vw/forum/viewtopic.php?p=3837416#3837416.

-- Regarding sleeping next to it, this mechanical noise of the compressor+fan is looking like a drastic change compared to the Dometic. I'm 10 feet from my kitchen fridge and 15 feet from my indelB. The indelB WAS louder than my house fridge.

I have since loosened the bolts holding the compressor down. The compressor was sitting on some pretty soft isolators but not so soft when mashed al the way down. Now it's floating, and noticeably quieter. The FAN however is a noisy little bugger and is hard-mounted to the fridge body (!) , so I will find a way to isolate it.
The Dometic was silent on 12v, silent on 110v and silent on propane, and silent when it doesn't work too....

-- It has a pretty loud "TINK" announcing that the compressor is starting. Also insulation to absorb the sound might be necessary. I'm curious how much it quiets upon stuffing it into a cabinet.

-- With the Fridge running on 110v in my house (at cool setting "5" of 7), it runs for 3 minutes on, 3 minutes off. To me, 50% duty is a LOT, to maintain 41 degrees refrigerated in a 68 degree house. It sat normal upright for 12 hours before I started it up. I shut it down for 4 hours then re-started too, and it's the same.

That's all for now.....
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Last edited by Sodo on Tue Jul 21, 2009 1:03 am; edited 4 times in total
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son1caaron
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PostPosted: Sun Jul 12, 2009 9:28 pm    Post subject: Reply with quote

i just got one of these about 2 weeks ago. I am also slightly concerned about the noise, but I don't think it is really much of an issue. After sleeping in hotels with extremely loud air conditioners that cycle on and off all night, this is nothing.

Also, regarding the cycling make sure you put something in the fridge. When the fridge runs and just cools the air inside there isn't much thermal momentum and it is going to warm up much faster. Once it is filled with food and drinks they will maintain their temperature and the fridge will not cycle as often.

Overall, I still think the truck fridge is a huge improvement over the dometic.
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Sodo
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PostPosted: Sun Jul 12, 2009 11:08 pm    Post subject: Reply with quote

>>> Cycling more often because it's empty

Good point! I'll put some stuff in it and see if it changes.



When I got my truckfridge CF49, the sound isolation mounts
on the compressor were tightened such that there was no float
in the mount and they let a lot of compressor sound into the fridge body.
They were mashed all the way down, which can't be right.

I loosened the bolts until I could depress the washer with my finger.
This took several steps because each time I backed off the bolt until
the washer was 'loose' the gooey rubber mounts would 'grow' over
the next few minutes and take up the slack. Eventually I ended up
with the isolators in a relaxed state where the washers would easily
press into the rubber away from the bolt, such that the compressor
moves a little if you push on it. And the fridge was noticeably quieter.

But it's still pretty noisy, in my opinion.

The next step is to suspend the condenser (which the fan is attached to)
to prevent the fan noise from coming into the body.

Image may have been reduced in size. Click image to view fullscreen.
[/img]
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Last edited by Sodo on Tue Jul 21, 2009 1:04 am; edited 2 times in total
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PostPosted: Mon Jul 13, 2009 12:08 am    Post subject: Reply with quote

Sodo wrote:
>>> Cycling more often because it's empty

Good point! I'll put some stuff in it and see if it changes.



When I got my truckfridge CF49, the sound isolation mounts on the compressor were tightened such that there was no float in the mount and they let a lot of compressor sound into the fridge body. They were mashed all the way down, which can't be right.

I loosened the bolts until I could depress the washer with my finger. This took several steps because each time I backed off the bolt until the washer was 'loose' the rubber mounts would 'grow' over the next few minutes and take up the slack. Eventually I ended up with the isolators in a relaxed state where the washers would easily press into the rubber away from the bolt, such that the compressor moves a little if you push on it. And the fridge was noticeably quieter.

But it's still pretty noisy, in my opinion.

The next step is to suspend the condenser (which the fan is attached to) to prevent the fan noise from coming into the body.

Image may have been reduced in size. Click image to view fullscreen.
[/img]



Do those bolts have a raised shoulder area extending from the head down, to prevent over tightening? Every compressor I have dealt with has shoulder bolts, and the bolts cannot be over- tightened. Yours look too tight( the "before" condition). I think you are correct in letting them relax a bit. Try putting some liquid threadlocker on them, for that extra peace of mind.
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PostPosted: Mon Jul 13, 2009 5:27 am    Post subject: Reply with quote

Good call on loosening the bolts holding the compressor to the fridge, I can actually feel a bit of a shudder in my van body when my VF kicks on, I assume mine are overtightened like yours.

The noise does bug my wife, but I don't really have any issues with it, but I will loosen the compressor bolts and will probably put some rubber washers under the condenser/fan mounting bolts too while I have it out.
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Sodo
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PostPosted: Mon Jul 13, 2009 8:08 am    Post subject: Reply with quote

>>> Test fridge with thermal mass inside....

OK I put 2X 1/2 gals of milk and a large bottle of Mayo.
12 hours later it still runs at 50% (3 minutes on; 3 minutes off) on setting "4" of 7 to maintain 38 degrees.

>>> Shoulder bolts.....

It has little 'sleeves' on the bolts, and they are 1/16" shorter than the relaxed height of the gooey rubber isolators.

1/16" squish seems about right in theory, but results in a FIRM hold-down. I backed mine off to the minimum, where the compressor is just "floating" on completely relaxed isolators, and the sleeve is doing nothing. If I grab the compressor and push it around I can see it move a little on it's suspension. The gooey rubber 'damps' well, it's clearly not going to 'buzz'. The threads and bolt 'quality' are about what you'd expect on a refrigerator. Loctite will be necessary to retain the adjustment.

>>> Rubber washers under the condenser

If there's any metal-to-metal, there is a path thru for noise. I'm going to work on that next. Probably using a strip of soft foam weatherproofing to suspend the condenser entirely. It will take some thought how to secure it without screws. It could be done the same way as the compressor, drill larger holes and use soft rubber grommets, but I'd like to know FIRST whether this refrigerator is "a keeper" when its duty cycle is 50%. I can't imagine how it could last very long.....

Pictures will follow then y'all can critique my method (unless somebody gets ahead of me).
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Sodo
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PostPosted: Mon Jul 20, 2009 11:33 pm    Post subject: Reply with quote

SO here's how I quieted the fridge down.
I eliminated all metal-to-metal connection to the fridge housing.
Including releasing the pressure on the compressor mounts,
isolating the condenser (and its fan) reduced the noise by half.

Which was a major success. I'm the one who chose the Truckfridge
and spent 1.5 full days working on it. I very much needed it to be
as quiet as possible. I will sleep like a baby as long as it doesn't
keep my wife awake. Remember this thing runs 3 minutes on,
3 minutes off, for its entire life.
Quiet is essential.

The goal is 100% supported by soft foam rubber and held down by rubber too.
As it was ----> I had to use what I had, which was weatherstrip and
rubber bands cut from motorcycle innertubes.
It's not pretty, but I had to keep moving.
And it's not easy because you CANNOT remove the condenser to work on it.
It's connected to the compressor with welded-on copper
tubing and the condenser fins are kind of fragile too.

If I had more time I would have ordered these soft gummy mounts from McMaster-Carr.
http://www.mcmaster.com/#9376k25/=2u5hod choose the
little 8-32 threadsize and choose material Neoprene

Image may have been reduced in size. Click image to view fullscreen.


View from the top.

Image may have been reduced in size. Click image to view fullscreen.




OK that's about as quiet as it's gonna get...
Installation PICS to follow.....
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....KTMs, GasGas, and a Stumpjumper
One apple every 8 hours will keep 3 doctors away - B Kliban


Last edited by Sodo on Tue Jul 21, 2009 9:05 pm; edited 5 times in total
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Sodo
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PostPosted: Tue Jul 21, 2009 12:23 am    Post subject: Reply with quote

OK here we go on installation.

Take the Dometic fridge out.
First thing is to shift the 110v outlet about 7/8" or so forward.
Image may have been reduced in size. Click image to view fullscreen.


Then screw four 3/4" blocks to the walls. Basically you have 7/8" of
space on each side and the top, which is available for more insulation.

Image may have been reduced in size. Click image to view fullscreen.


Pull the rubber T-molding out of the plywood bezel. You will be cutting
1/8" off the right side, and 1/4" off the left, and cutting UP to within 3/4" of the top.

A good way to do it is by using 3/4" blocks. Mark the backside of the
plywood bezel. Use a block to mark the top at 3/4" also.
Remove the bezel and draw a rectangle that is about 1/8" taller
than the truckfridge body NOT counting the height of the feets,
because they are narrower than the opening in the bezel. Your bottom
corners will look a little better if the cut ends a little higher than mine Shocked
---------> (the height of the feets) .

Image may have been reduced in size. Click image to view fullscreen.


Put some kind of support. I used 1.5X 3" Aluminum angle.
It needs to be 14 inches long. The fridge feets slide on this
when you push it into the hole.

The blocks are just behind the bezel, ready for the four front screws.

I used 2 rolls of 2" thick insulation from Home Depot. It is 16" by 48".
I bet this adds a LOT of insulation to the fridge, and hopefully absorbs noise.
I chose soft fibreglas over PolyIso & styrofoam, because those insulations
let sound through and the harder stuff seems to amplify.


Image may have been reduced in size. Click image to view fullscreen.


Insulation was stapled to the sides and top. Insulation on the bottom
is clamped at sides, leaving a place for the feets to slide. A passageway
is left at the rear for air to travel upward on the condenser side.

Image may have been reduced in size. Click image to view fullscreen.


An angled wall is placed at the back which leaves a 1" X ~15" opening for air.
The thin panel 'floor' is mainly as a 'roof' over the storage cubby. The panel
is spaced downward 1/4" and the fridge 'feet' allow more space for the insulation.

Image may have been reduced in size. Click image to view fullscreen.


I cut the bottom off the original refrigerator door and used it to cover the hole.
I used the original hinges, which is not easy. It involves machining a
narrow slot by pushing a 5/64" drillbit sideways. Shocked Shocked I can take more pictures
of how I used these hinges if anyone is interested. It's held closed with
rare earth magnets. A nice big frying pan with dinnerplates fits inside
which is a real PLUS as their size dominated the other cabinet.

Image may have been reduced in size. Click image to view fullscreen.


Here's the finished look. Notice that the lower door is 1/2 inch lower
than the forward cabinet, that's because I cut the plywood all the way
down to the metal grating to get the biggest door possible.

Image may have been reduced in size. Click image to view fullscreen.


I haven't yet tried to sleep with it but it's pretty quiet.....
Next project is to change the black front panel to the Westy gray.

Hope this info helps someone!
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....KTMs, GasGas, and a Stumpjumper
One apple every 8 hours will keep 3 doctors away - B Kliban


Last edited by Sodo on Tue Jul 21, 2009 2:30 pm; edited 7 times in total
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RadioRental
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PostPosted: Tue Jul 21, 2009 3:45 am    Post subject: Reply with quote

I'm curious about where/how the condenser is going to release heat. I havent personally started pulling my dometic apart and I didnt see where you're venting the air. But the ability to exchange heat is going to determine how warm the inside of your fridge gets. Its all relative, if its really warm back there then the inside of the fridge will only become slightly less warm.
I would not rely on convection alone to get the warm air away from the condenser & fan with that much insulation back there.

But, that said, I'm usually more than 50% wrong on average.
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PostPosted: Tue Jul 21, 2009 6:37 am    Post subject: Reply with quote

RadioRental wrote:
I'm curious about where/how the condenser is going to release heat. I havent personally started pulling my dometic apart and I didnt see where you're venting the air. But the ability to exchange heat is going to determine how warm the inside of your fridge gets. Its all relative, if its really warm back there then the inside of the fridge will only become slightly less warm.
I would not rely on convection alone to get the warm air away from the condenser & fan with that much insulation back there.

But, that said, I'm usually more than 50% wrong on average.


I was wondering the same thing. I noticed the gap at the back of the modified storage, but I think you need air flow across the condensor to remove the heat. Ideally it would exhaust outside the van, but that requires more dreaded holes into the chassis. Other wise the heat is disipated into the cabin as with the Dometic. Other than that, great documentation and photos. Thank you
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PostPosted: Tue Jul 21, 2009 7:48 am    Post subject: Reply with quote

[quote="rsxsr"]
RadioRental wrote:
the heat is disipated into the cabin as with the Dometic.


Yes its the same as the dometic, the main difference here is that more
insulation reduces the amount of cabin heat re-entering the fridge thru the sides.

The fan blows air from vehicle back to front. I don't know how much comes from
below the fridge, but the instructions specified that 10 sq. inches of air be allowed
to enter from the bottom and convect up the back.

It would be an improvement to move the heat outside the van.
But that's a lot more difficult than poking a new fridge into the same cabinet.
The installation alone was hard enough that can wait. Laughing Laughing
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PostPosted: Tue Jul 21, 2009 8:03 am    Post subject: Reply with quote

Sodo,

Another hurrah for very nice photos and write-up.
Good post!
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PostPosted: Tue Jul 21, 2009 8:24 am    Post subject: Reply with quote

Very nice install Sodo, and kudos on the pictures.

I think the keeping the heat in the van is a good thing...but then I mainly camp in the cold Canadian Rockies!

Cheers!
Dave
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PostPosted: Tue Jul 21, 2009 9:06 am    Post subject: Reply with quote

Excellent build and great tips/feedback on sound dampening.

I'm just getting hung up on the fact that the fridge is cycling so much. I would say that I thought you had put insulation around the side of the fridge for noise dampening... "the main difference here is that more insulation reduces the amount of cabin heat re-entering the fridge thru the sides" I think you may get more bang for buck without that insulation!!

'heat' will get in to the fridge through the condenser if the ambient temp is high. Even though the device might have temp control, the mechanical exchange of heat is relative, not absolute.

The more air you get to the condenser, the closer the back of the fridge will be to ambient, the less it will have to work, battery will last longer, food will get colder more quickly and wifey will be happy with less noise.

Given you're not trying to blast freeze anything here, I would say the existing insulation in the design is sufficient for the job, let that condenser dissipate heat in to a larger volume of air.
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PostPosted: Tue Jul 21, 2009 9:43 am    Post subject: Reply with quote

RadioRental wrote:
I think you may get more bang for buck without that insulation!!


Yes I understand, I don't like being mediocre but half the time I'm below my own average too! Laughing Laughing

On the insulation though...... Basically the heat rejection system is per MFR spec, but extra insulation
reduces the amount of heat coming into the cube thru the 6 sides. So I think I came out ahead....

Here's my logic.

Heat ALWAYS exits the fridge at the condenser. Increase the air-flow, and the fridge doesn't have to work as hard.
This I did per the MFRs specs, so no 'increase' here.


Heat ALWAYS enters the fridge thru the six sides, this is the steady state source of incoming heat (that the condenser must reject).
I decided that since I had an additional 7/8" all around, more insulation will reduce the amount of incoming heat
(and the fridge doesn't have to work as hard).


Not having any better numbers than the MFR recommendation, I decided to follow the MFR ---->i.e. providing a minimum of 10 sq inches
of convective duct area coming from the bottom. Basically I choked it down with all that fluffy insulation, to slightly exceed MFR
recommendation. Another way I can envision increasing this airflow is to add another fan, but that is more noise and more electricity.
Will it pay off? Not sure. For now, following the mfr recommendations is enough. I'll let someone else work it further,
there are a lot of wizards on this list - let's see the creative solutions! Wink Wink

It was fun but I'm tired of working on the van -----> my next project is to SLEEP in the van with my new fridge then try it on the wife! #Sleep #Sleep
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PostPosted: Tue Jul 21, 2009 9:45 am    Post subject: Reply with quote

RadioRental wrote:
I think you may get more bang for buck without that insulation!!

'heat' will get in to the fridge through the condenser if the ambient temp is high. Even though the device might have temp control, the mechanical exchange of heat is relative, not absolute.

The more air you get to the condenser, the closer the back of the fridge will be to ambient, the less it will have to work, battery will last longer, food will get colder more quickly and wifey will be happy with less noise.

Given you're not trying to blast freeze anything here, I would say the existing insulation in the design is sufficient for the job, let that condenser dissipate heat in to a larger volume of air.


agree 100%
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PostPosted: Fri Mar 26, 2010 8:03 pm    Post subject: Reply with quote

The MFR said to give it minimum 10 square inches of airflow and I gave it 14 square inches. Adding more insulation would ensure a net increase in performance per Amp. I'm pretty sure I came out ahead.

However, my assumptions for how a fridge OUGHT to manage it's power consumption was wrong! It doesn't choose it's runtime based on temp or incoming heat, or even airflow, it simply runs the fan and the compressor 3 minutes on / 3 minutes off, all day and all night, like a moron.

OTHER THAN THAT.... The fridge is a nice size, and it's been very reliable. Freezes ice cubes. It's great for driving. It needs a better control system, which I think I can solve by putting a programmable thermostat inside.

But to sleep I have to turn it off at night. It even runs 50% when it's colder outside than in the fridge. Crude!
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PostPosted: Fri Mar 26, 2010 10:30 pm    Post subject: Reply with quote

Sodo,

See pg 4 of this thread. The poster moved his thermostat capillary tube to a different location within the fridge to get longer periods between compressor cycles of his vitrifrigo. Since they are the same fridge, maybe this will help.

I just pulled the trigger on a TruckFridge 49, so I am very interested in optimizing the amp hours available.

Mark


http://www.thesamba.com/vw/forum/viewtopic.php?t=3...p;start=60

FROM THE THREAD
After installing my Vitrifrigo and the four UB12220 batteries, I tested the new setup and was disappointed with how much battery power it was using.

Using the Volt~Minder (voltminder.com) to monitor my battery condition I wanted to see how long I could run my fridge before the batteries were down to 12.2v (50% depleted). I double checked my batteries using a voltmeter and confirmed that the Volt~Minder is accurate.

To test the fridge, I turned in on after fully charging the batteries using the Iota DLS-30/IQ4 smart charger. The battery was higher than 12.8v but that was due to a surface charge. I turned the fridge on at about 11:00pm one evening and ran it until about 10:00pm the next evening (right at 24 hours without starting the engine) and I had the fridge set at about the 1/2 way point trying to keep the temp in the high 30's. After 23 hours, the batteries were down to showing 12.2v (50% depleted) and the Volt~Minder was beeping to let me know that the batteries were down to the level I had set for an alarm.

As a second test, and to make certain my UB12220 batteries were not defective, I took a fully charged group 41 starting battery and did the same test and after about 11 hours overnight, it was down to 12.2v with the temps in the 50’s and rain. Since the group 41 should have about 1/2 the amp hours of the 4 UB12220 batteries, the results seemed consistent.

Based on Karl’s experience with the Vitrifrigo, I was expecting the fridge to run much longer on a full charge of the UB12220 batteries especially since the temps here have not been very high.

Bringing the fridge into my workroom and running it off of AC and DC, I did a lot of experimentation to see what was happening. Timing the fridge on/off run times, I found that running on DC or AC and with the fridge empty or full, I was getting a 1:1 ratio of run to rest. In the course of working on the fridge, I found that the fridge also had two holes in the back that were not caulked well. One was where the fridge light control entered the fridge and the other was where the thermostat and refrigerant line entered the fridge so I caulked both. There was also a tear in the insulation around the refrigerant line so I replaced the insulation with some thicker refrigerant line insulation and covered it with silver tape. Even after doing this, I was still getting a 1:1 run to rest time.

Knowing that Karl was getting a 1:3 run to rest, I figured I had a defective fridge so I called Vitrifrigo and spoke with their tech person. The guy was very patient with me and I spoke to him on three different days while I tried different things he suggested to get my fridge running better. With other temp tests, etc. it was determined that my compressor was working fine and that the fridge was not defective.

The tech guy finally took a new fridge out of a box and hooked it up on AC overnight with the temp dial set in the vertical position and the next morning he called and said his fridge was also giving a 1:1 ratio of run to rest.

He did say that the thermostat was very sensitive and using two digital thermometers and varying their locations, I found that the thermostat was turning the compressor on after a temp rise of only .2 degrees. So a 38.4 temp that rose to 38.6 would cause the compressor to turn on. I figured that a .6 degree temp rise would probably give me close to the 1:3 run to rest time that Karl has reported. Upon the tech’s advice, I varied the placement of the capillary tube and found that the capillary tube placement and thermostat setting did indeed have an impact on the sensitivity of the cut on point for the compressor.

I finally found a thermostat setting and capillary tube placement where my original .2 degree sensitivity for the compressor cut on was increased to about .6 degrees and my ratio of run to rest improved from 1:1 to some variation of 1:2 to 1:3 when the temp inside is 38 degrees. This should make a huge improvement in how long the fridge will run on a full battery charge.

With all of my temp measurements, I did find that the inside back bottom of the fridge and the front bottom have a temperature variation of about 3 degrees. When the back registered 38, the front registered ~35 degrees. This was consistent over a week of testing with different settings.

During all of this testing, it appeared to me that the outside of the back of the fridge was a little cool so using foil faced bubble wrap, I put more insulation on the back and then proceeded to put some on the sides, bottom, top and even behind the door panel. Whether this addition will have any impact is unknown since I was tired of testing.

Unless something happens, sometimes this week, my wife and I are about to take off for two months on a trip from Virginia to Newfoundland so I will see if all of this works. If not, when we get back, I may replace my thermostat with a digital one where you can set the cut on/off range.

Pictures of my modification are at: http://picasaweb.google.com/teerhb/UpdateToVitrifrigoInstallation#

Hope this helps someone,

Harold

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Sodo
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PostPosted: Tue Jul 06, 2010 11:58 pm    Post subject: Reply with quote

Thanks for the tip, Mark.

Anyone else have actual success .... in modifying the truckfridge control system?

I find it rather infuriating that a 12v fridge designed to run on batteries....... runs 50% on / 50% off regardless of ambient temp. Even when outside it's 40 degrees F the dumb thing just gulps my batteries.

This just seems so stupid, that I think I'm missing something. Is there possibly a control system adjustment in the thermostat box that allows the inside temp to rise a bit more before turning on?

Lots of refrigeration controls here: http://www.drillspot.com/products/686513/ranco_a30-2210_temperature_control Wonder if any of these controls have a better run/rest cycle to save battery power.
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presslab
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PostPosted: Wed Jul 07, 2010 12:18 am    Post subject: Reply with quote

Sodo wrote:
Thanks for the tip, Mark.

Anyone else have actual success .... in modifying the truckfridge control system?

I find it rather infuriating that a 12v fridge designed to run on batteries....... runs 50% on / 50% off regardless of ambient temp. Even when outside it's 40 degrees F the dumb thing just gulps my batteries.

This just seems so stupid, that I think I'm missing something. Is there possibly a control system adjustment in the thermostat box that allows the inside temp to rise a bit more before turning on?

Lots of refrigeration controls here: http://www.drillspot.com/products/686513/ranco_a30-2210_temperature_control Wonder if any of these controls have a better run/rest cycle to save battery power.


If you take a detailed pic of the control board, I might be able to recommend a modification. To reduce the frequency of cycling you want more temperature hysteresis. This is probably doable by soldering on an additional resistor.
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