WAECO FRIDGE FAN MODIFICATION
CF50-DC 120mm can be fitted to replace 90 mm original fan
CF50-AC Ver A can also be fitted with a 120mm fan
CF50-AC Ver B 90mm fan can only be replaced by a higher volume 90mm fan
So I have replaced the fan in the CF50 DC which is the older style fridge with the dots that show the temp setting. Took about 30 mins and a soldering iron, screw driver and a pair of pliers. The original fan was full of dust and is not IP rated as you can see the internal coils of the motor.
CF50 original fan
Original fan was .280 amp draw and about 40 CFM. The new 120mm fan (cat no YX2522) is .380 amps and is 80 CFM based on info from Jaycar, . New fan also has a an IP rating of 55 and has a ball bearing instead of a sleeve and works fantastic. Downside is that the noise is increased but for my needs it would not bother me. You can actually feel the heat coming out the other side of the vents.
It was all very easy, I started by taking the cover off and removing the fan, swapped over the rubber grommets and threaded inserts for screws, put the new fan in place and soldered the new wires to old. It really works well
Good one Dave, for the extra 100mA it should be a great improvement.
Those fans, both the original and your replacement, only act on about 25% of the condenser area but there is no alternative due to space limitations. Of course the air also cools the compressor and your increased flow will help that too.
Cantiva, I reckon your right about the thermistor. They are available in different sizes. I did not worry about it too much as I am only drawing an extra 0.1 amp and it could be one more thing to go wrong. The above 120mm fan is quite noisy so I would not recommend it for a caravan fridge. For this I would recommend maybe a higher flow 90mm fan. I am thinking how a variable speed fan may go so you can operate on the lower quieter speed and when needed flick a switch and let it rip. Or 2 smaller fans with a switch between them to bring on the second fan when needed. cheers, Dave
The original installation is quite inefficient because air takes the path of least resistance - it just flows from the fan output to the fan input. A little fresh air gets sucked in and a little hot air gets blown outside the enclosure.
I improved efficiency by putting a baffle around the fan. Incoming cool air must flow over the coils and must leave via the grill on the other side, again flowing through the coils.
Fan control doesn't really help much - the fridge controller already controls power to the fan so it runs only when needed.
Once you have a baffle in place, you realise that full cooling is useful whenever the compressor is running - the outgoing air is quite hotter than incoming air.
I would like to add some ideas to it if I may. Regarding fan setups like this, you will benefit greatly by adding a form of shroud so that the air has to be drawn thru the condenser, and can not be redrawn from the output side of the fan. You would be surprised at how much air eddies around the edges of fans from the out to the input side. Adding a shroud to this setup, so that the air has to go over the condensor, thru the fan, and then out the other side would make a good difference again. Added benefit of the shroud could be that even though the fan covers 70% of the condenser, the shroud would improve the airflow over the areas that are not directly behind the fan. Just thoughts, again, good setup, worthy addition to the fridge. As an idea, using some windscreen reflective bubble material between the fan and the condenser, with fan sized hole, and sealed to the fan so no air can leak past the fan and shroud would make quite a difference, can you mount the fan back 25mm from the condenser to aid this. The shroud could then be made to fit cleanly out to the edges of the compressor space. One sided self adhesive foam used for door sealing can also be helpful in these applications. Again, great idea, just wanted to add something to make it better if you have the time.
Trains, last week we went away with my fan modified CF50 and standard CF 50 and gave them a good run in some hot weather. On the std fridge you can actually feel the hot air "leaking" out of the intake vent and recirculating back to the input side of the fan as you say, so it will definitely help by fitting a shroud around the fan. The modified fridge simply blasts all the air through and out the other side without a problem and does not recirculate any air at all, but it is a DC model with less components inside. When you look inside an AC model I can not see how the air can get past all those obstacles and it is no wonder that it wants to take the path of least resistance as Mike has mentioned above.
We hope to modify the other fridge in the near future and we may incorporate a shroud. We also may install a small circulation fan to supply the dairy section with colder air in the near future so stay tuned. Thanks for your input and if anyone decides to do a mod, if possible could you please supply some pics. Many thanks.
Rob, if your checkerplate box doesn't have any openings in it to allow cool air to enter and hot air to escape, you will have problems with your fridge and it will always struggle to get cold regardless of your slide switch. If this is the case you may need to modify the box to allow for some air flow. You could try taking it out of the box and run it for a while and if it operates better you will know the cause.
Having added the extra fan I gave the project some more consideration.
The original single fan drew air in from one side, through the condenser, over the compressor, through the other side of the condenser, and out through the vents in the housing. A difficult task for the little fan and the second half of the condenser was receiving the hot air from the first half.
When I initially added the second fan on the opposite side of the condenser I had the choice of fan air direction. It could have simply continued the existing air direction but I didn't think that would help much so I arranged it to also draw air in on that side, over the condenser etc. but did not give much thought to where the hot air would exit the housing. So I took another look at it.
What I have now done is to drill a pattern of 12mm holes in the centre section of the plastic housing for the exit air. Air is now drawn in from each side and out the centre. The air flow has been very much improved as evidenced by a very scientific piece of paper dangled in front of the exit holes.
Image 1
It was necessary to be aware of the circuit board attached to the inside of the moulding shown in Image 2.
Image 2
With the circuit board removed the mounting posts can be seen in Image 3 and the holes were positioned to avoid these.
Image 3
Image 4 shows what lies behind the housing moulding in this area.
Image 4
It was a brave move to get stuck into drilling the housing and I would only recommend doing it if you are confident. Certainly remove the housing moulding from the fridge body and dismount the attached internal circuit board before proceeding. Only field use under desert conditions will really tell if this has been a significant improvement but I am confident. Just taken some measurements which may be interesting. Waeco 35 litre. Ambient in my workshop: 36c Temp in fridge: -4c Run time: 6m 40sec Off time: 6m 20sec Running current: 3.6A So, near enough to a 50% duty cycle which means it averages 1.8A under these conditions. Probably better during cooler night hours. Probably worse if fridge is being opened to get stuff out. So, my 110Ah battery discharged to 60% SOC will run this fridge for about 24 hours. Adequate for my style, but only just. I will either hafta keep the vehicle moving or get some solar gear! Pity I didn't take some measurements before I did the mods for comparison.
Some interesting approaches to providing more air flow.
One thing I would be considering is this. Air flow over the condenser where it’s behind the compressor, and near the cabinet. Would it be better form to have the 2nd fan same side as the original one, but placed right up against the cabinet fixed to the outside cover, so that in effect, it blows air down the side of the cabinet and condenser, and provides a bit more air to the current fan. The benefit of drawing clear air from outside by sealed/ baffled fan has already been mentioned, and proven above too with the supercheap unit. Just a thought, I too enjoying getting the most out of things, and its always good to get the most out of your battery by an efficient fridge.
I have finally installed another fan mod to my CF50. The pic below is my test setup and eventually I will draw power from the light supply. It has really worked well and I have the headache to prove it. It is simply a small fan glued onto some pipe and draws air from coldest part of the fridge compartment and directs it into the dairy compartment. It will then flow back over the top of basket and circulating through the rest of the fridge contents. It allows me to have access to drinks without having to rumage around. If you do want to utilise the dairy compartment for its intended use then I suppose you could spin it around so it redirects to the fridge only. Fan is 40mm and pipe is made from bits from a 40mm S+P trap and a 40mm adjustable cap and lining, both from bunnings. Cheers, Dave
40mm fan mod
output side of the switch (middle set of terminals) to a audio plug base mounted in the light lens. The fan has a male plug to suit. This way I now Have the options of fan on/off with the condensor fan (only on while running) or on all the time (via the light power) and can be unplugged to remove the unit from the fridge with the basket. Hope this makes sense