Fridge Temp controller

stevemc181

Well-Known Member
#1
I bought a couple of Engel Eclipse fridges a while back at a price I couldn't pass up. One thing that has always annoyed me is the dial style temp control. As most would know, it's just a dial that you set from 1- 5 and it doesn't actually tell you what temperature it is being set at.

While the temp seems to be stable when monitored with a wireless thermometer, I prefer to have a way of just setting it to whatever temp I want and forgetting about it. I've seen this idea on other forums so thought I'd give it a go.

I bought two Willhi WH7016C temp controllers on ebay for about $12.00 each, as I have two fridges to run, one stays in the Paj permanently and the other is used on extended trips. The units I have are only 5amp rated, which is why I used relays, but I've since seen 10 amp rated units which would make the wiring a bit simpler.



I found the wiring diagram that comes with the units was woefully inadequate and a search of the net gave me some clues on how to wire them with relays, I've made a few changes to diagrams I found and have them wired as below using automotive relays. These are wired pre the engel socket connections that I already had installed in the car, so it's just a matter of plugging in the engel as normal, drop the temp probe in and set the temp etc. I bought a Jiffy box from Jaycar to fit the units in and have it attached to the top of my fridge cage within view of the rear vision mirror, this way I can see if their is a problem easily, as the units will flash when it is under or over the temp by whatever you set the alarm to.

These units have multiple settings for Hysterisis etc and can be set in 1° increments to kick the fridge back into action. At the moment I have set one of them at -2°C. It will switch the fridge off when it hits -2°C but the temp will continue to drop for another degree or so. When the temp rises to 0°C, then it kicks back in and lowers the temp. I have had them running for a couple of weeks now and all seems to be working well, Nice cold unfrozen beers!

The Engel dial is just left on setting 5 and the controller switches the fridge on and off and is basically set and forget.



Sorry for the poor pics, but you get the idea.



 

stevemc181

Well-Known Member
#4
Fantastic idea - much cheaper than the Engel / Waeco Thermometers too

cheers
Yep, much better than just a thermometer, as they control what is happening rather than just report on temperature. For the money and what they do, they are a bargain. These are commonly used in the aquarium and home brew worlds. I also have a wireless thermometer that monitors two fridges and it was nearly 4 times the price of these units, but I wasn't happy with just monitoring and wanted better control on the temps.

I also have it wired, so if they give me any issues, I just swap two wires over in my distribution block and my engel plugs are back to normal.
 

BarKer

Well-Known Member
#5
Interesting... Have you considered that the Engels might not be designed for the constant power on and power off for the whole unit ?

It is a good way to keep the temp constant tho, especially at night.. So far as I know only the current 32 and the 40 liter digital steel jobbies adjust themselves for varying outside temps whereas the other models work more on a duty cycle principle.
 

stevemc181

Well-Known Member
#6
Interesting... Have you considered that the Engels might not be designed for the constant power on and power off for the whole unit ?

It is a good way to keep the temp constant tho, especially at night.. So far as I know only the current 32 and the 40 liter digital steel jobbies adjust themselves for varying outside temps whereas the other models work more on a duty cycle principle.
Yep I did consider it and then promptly ignored it, and decided to test it myself as there seem to be plenty of others out there doing similar without issue. These units have various settings to avoid firing up the compressor with minor temp fluctuations, so I think they should be ok.
I think the Engel eclipses may also adjust themselves, as the temp seemed to stay pretty constant day or night. I'd just prefer a digital thermostat like these, instead of the initial guess work. They seem to be working ok, and one fridge has been running hooked up to the thermostat constantly for about 2 weeks now, with no issue. Time will tell I guess.
 

BarKer

Well-Known Member
#7
Yep I did consider it and then promptly ignored it, and decided to test it myself as there seem to be plenty of others out there doing similar without issue. These units have various settings to avoid firing up the compressor with minor temp fluctuations, so I think they should be ok.
I think the Engel eclipses may also adjust themselves, as the temp seemed to stay pretty constant day or night. I'd just prefer a digital thermostat like these, instead of the initial guess work. They seem to be working ok, and one fridge has been running hooked up to the thermostat constantly for about 2 weeks now, with no issue. Time will tell I guess.
promptly ignored it :).. wish my work was like that.. I am pretty the Eclipses work on the duty cycle theory..

Don't get me wrong, I think it is a great idea as it takes away having to think about the fridge and temperature settings..
 

stevemc181

Well-Known Member
#8
promptly ignored it :).. wish my work was like that.. I am pretty the Eclipses work on the duty cycle theory..

Don't get me wrong, I think it is a great idea as it takes away having to think about the fridge and temperature settings..
Yes, I thought the eclipses were also on a duty cycle, but the temp stays constant day and night when just using the dial, which seems to indicate they do have some kind of thermostat control. It was pretty mild weather these have been tested in though so maybe just not enough temp difference to tell?

I'll keep the digital thermostat running on one fridge constantly for the next 3 months and make sure all is well beofre heading off on a 4 or 5 week trip in October so if all is well, I'll load the 2nd fridge in the Paj and hook it up to the other controller.
 
#9
Just a few thoughts to add to the discussion!
With his set up you have a back up if the external controller stuffs up you can always go back to using the original thermostat.
just note that the thermostat in fridges are inside the fridge cabinet. So the dial control is effectively setting the temp inside the fridge, it does not matter what the outside temp is. once you work out what number on the dial is the temp you want in your fridge, Then it does not matter if it is 35 degrees outside or ten it will work to get to the temp you are after.
Of course in hot temps it has to work harder to maintain the temp you want but it will get there.

The only thing problem I can see with the external temp controller is that you are changing what the manufacturer has determined as the most efficient control to turn the compressor on and off so you could be using more power than necessary.
The other thing is that some fridges have a time delay when initially turned on or connected to power, can be up to 5 minutes before the compressor will start to protect the components(incase of dodgy power source). This could mean there is a long delay every time the external controller turns the fridge on creating a bigger fluctuation in temperatures inside the fridge.

Just a few thoughts to add to the discussion.
 

stevemc181

Well-Known Member
#10
All is still going well with the one fridge that is powered permanently in the back of the Paj, my beers are just above freezing point with a little frost appearing on the glass. I have a carton of Corona's in there in case of an emergency requiring thirst aid :p

The temps are stable and set to stay within a 2°C, range, the fridge kicks in at just above 0°C and switches off at -2°. The actual temp is about a degree out, (reads -2° when it is actually -1° according to an accurite wireless thermometer I also have in there) but I haven't bothered adjusting the thermostat to account for this. This is most likely due to me extending the temp probe wires and giving a slightly inaccurate reading.

The controller can be calibrated to adjust for incorrect temps, I've just been lazy and haven't worried about it. There are also adjustments for compressors requiring delayed starts etc, I haven't used any of those. So far all seems to be going well.
 

muc the truck

Well-Known Member
#11
How did you get the temp probe in the fridge and make a good seal . great idea with those cheap little temp controllers . I seen a truck with one hooked to his aircon as he was sick of either being frozen or hot with the old systems to make climate control
.
 

stevemc181

Well-Known Member
#12
How did you get the temp probe in the fridge and make a good seal . great idea with those cheap little temp controllers . I seen a truck with one hooked to his aircon as he was sick of either being frozen or hot with the old systems to make climate control
.
It's a pretty thin wire going to the temp probe, so it's just thrown in there and zippy tied to the fridge basket and the wire just hangs over the top. Doesn't seem to bother the seal too much.
 
#13
4+ years down the track, I was wondering if you're still using this setup?, and have you've had any issues with the fridges or controllers?

Cheers :)
 

stevemc181

Well-Known Member
#14
4+ years down the track, I was wondering if you're still using this setup?, and have you've had any issues with the fridges or controllers?

Cheers :)
I changed to a different fridge, Kickass 89 litre dual zone and sold my two Engels about a year ago. I had no problems with them at all in the few years they ran like this. The new fridge has its own digital and wifi controls, so the setup was no longer needed.
 
#15
I changed to a different fridge, Kickass 89 litre dual zone and sold my two Engels about a year ago. I had no problems with them at all in the few years they ran like this. The new fridge has its own digital and wifi controls, so the setup was no longer needed.
Thanks, that's good to know... I'm not a fan of the knob control so I think I'll go this way...
 

billolga

4x4 Earth Contributer
#16
Thanks, that's good to know... I'm not a fan of the knob control so I think I'll go this way...
The new Engels you can set the temp & it then shows the temp.
I never had a problem with the old engels I had for 18 years - just set it at around 2 & used a cheap wireless temp to monitor it.
 
#17
The new Engels you can set the temp & it then shows the temp.
I never had a problem with the old engels I had for 18 years - just set it at around 2 & used a cheap wireless temp to monitor it.
This Engel Eclipse is the first 12v fridge I've owned, I still have a lot to learn, I only bought it a couple of days ago, 9+ months travelling over the last couple of winters I've made do with an eski...

The reason I was looking at better temperature control is because I've heard numerous people complain about the dial control, and because I often abandon the van for a week or two at a time so the fridge will be unattended at times, and with temperature variations in the van from near zero to 45+, I figure better temperature control might be a good idea...
 
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