Computer fan in IndelB fridge (Webasto SECOP)

[coopso]

Has anyone tried upgrading their Indel fridge to make it quieter? I have a feeling the compressor is a little bit louder than the fan but obviously it's not practical to replace that whereas a fan should be a simple swap out!


So I would like to replace the fan in my IndelB fridge with a quieter one. I see there is some fan expertise here from other threads (@Sternwake) !



The existing fan is a two wire Young Lin Tech Ltd model DFB 922512L 92x92x25mm 12V 1.6W.


I found a spec here: http://www.tmfan.com/doc/ball%20bear...DFB922512L.pdf

The fan is connected to the SECOP fridge controller described here.


The document states the controller can supply a continuous power of 6W. The document states that fan speed can be adjusted from 40% to 100% - since this is done with only two wires presumably the controller is using a PWM signal on the +ve fan input wire.

I've been in contact with Noctua who advise that all their fans require a permanent 12V connection and a separate PWM connection (so are 3 or 4 wires).


I have spent hours googling for 2 wire fans with PWM but haven't found any! One idea I have for a workaround is to take the + for the fan input from an alternate source and connect the fridge PWM signal wire to the PWM fan connection (3 wire fan). I'm not an electrician so not sure if that would work, plus I have a feeling that there are multiple PWM implementations out there.


Any ideas? Thanks.

[Sternwake]

I was unaware that the Secop compressor controller now allows for PWM speed controlling of the fan. Mine, 2012 era, does not.

The 92mm fan on your condenser, how much of the condenser does it cover?

Computer fans do much better, airflow and noise wise, when the restriction is not directly behind the fan blades, but in front of them, meaning they should push air into a restriction, rather than try and pull air through one that is close behind the spinning blades.

I have some experience running noctua fans through a PWM speed controller, but more experience running Noctua fans through their NA-FC1 speed controller which controls the speed via the 4th wire.

All noctua IPPC 3k rpm fans that were speed controlled through their controller, died, and Noctua replaced them all, quickly, free, and asked for the failed units back sending the paperwork and shipping label to return them to Austria.

I know of one person online, who claimed to have no issues running several IPPC noctua 3k rpm fans through a PWM motor speed controller, on the yellow and black wires. He claimed there was no weird whining, but they were in a location he would not likely hear them whine.

If using a PWM motor speed controller( or LED dimmer) , look for one that advertises 21khz or higher, so only Fido can hear the potential whining of the motor windings.

I have no idea the Khz of the secop controller's fan output.

I have no personal experience running the IPPC noctuas on a 21khz PWM motor speed controller for extended periods, only short durations and they responded well to them.

After I gave up on the IPPC industrial Noctuas, I tried their na fc1 controller on some Delta 4 wire PWM fans, using only the blue pwm signal wire and it worked OK to speed control the powerful deltas, but I compared the speed range and amp draw and found using a xl4015 based voltage bucker had better speed range, going to much slower before shutting off the fan, and it used slightly less amperage throughout its range.

I now ONLY use XL 4015 voltage buckers for fan speed control and LED dimmers. 5 amps max. 0.18v drop. 12.8v in 12.62v out max.
Inconsequential drop, in my opinion, easily made up with thicker wire feeding the fan.

It does require removing the tiny trimpot adding wires to a larger fingertwist trimpot, whereas PWM MSC's come with a fingertwist potentiometer.

If you can fit a 120mm fan on your condenser, and orient it to push air through the condenser, it will be quieter, and more efficiently remove heat from the fins.

I had the Noctua NF-F12( 1500 rpm non industrial version) on my Vitrifrigo c51is for about 5 years then tried the Noctua A12x15. The 10 mm thinner width of the latter allowed my particular insulated cabinet to flow a bit better, in theory. It was quieter.

The 92 fan you linked has 43 cfm, but cfm ratings are with Zero restriction.
It claims to draw 0.12 amps.

The Noctua NF-f12 has ~ 53 CFM, but very high static pressure rating for such a Quiet fan. It also only draws 0.05 amps .

The newer Noctua a12x25 is the computer nerd's new favorite as it does well both in cfm with no restriction and has a relatively high static pressure rating for when there is.

I bet these Noctua fans will have little issue being fed PWM on teh yellow and black power wires. Will they last their 6 year warranty period? I know not, but I suspect Noctua's recommendation to only feed them 12v and speed control them by the 4th PWm wire is simply a CYA for minimal warranty returns. I've greatly exceeded 12v on all their 12v fans.
But I could certainly be wrong.

The only failures of Noctua fans I've had, were the IPPC industrial versions that were speed controlled by their own NA-fc1 controller. That 4th wire( blue) its connector and where it attached to the circuit board at fan hub, would grow corrosion no matter what and I believe was the cause of failures.

One other Noctua fan, a 60mm I use on my ajustable voltage power supply, had its _+ wire rotted off the circuit board and was easily returned to life and been going 3+ more years since. This fan has seen extended periods of 15 volts and more rarely, upto as high as 19v when I am charging a distant battery over too thin of cabling and want 14.7v at distant battery terminals.

I now peel back the sticker on every computer fan's hub, and paint over these solder joints with clear nail polish, or stuff some 'amazing goop' in there, on every fan I employ, and no more failures of any fan since.

[Mr B]

I have a 6 inch, 12 volt computer fan on my Dometic fridge, It has a green Led on when its running, The whole fan glows, It looks great and keeps the pipes cool, Uses bugga all electricity,
Its on a single 12 volt switch, two wires, Its not adjustable,
Its extremely quiet, Runs off my battery bank, Charged by my Solar Panels,
It came from China on Fleaybay, $8-00 delivered,

[coopso]

Thanks folks, I will order the Noctua F12 and an adaptor, will paint the joints with nail polish and mount the fan in reverse. Thanks for the tips! I'll report back.

[coopso]

I've installed the fan, was a pain because the adaptor whilst clearly marked as 92->120 does not fit a 120mm fan! Anyway some judicious use of zip ties has resulted in the fan successfully being installed. For now it is oriented the same way as the original was (i.e. is blowing air out of the unit). Seems to be fine for now, I may switch it round later (I need more zip ties!).


So the fan is nice and quiet. Thanks for the advice,


But the noise from the compressor itself is really intrusive, especially when it first comes on. I'm guessing I have to live with this, but here's a video in case anyone has any bright ideas. The fan is disconnected so the noise that can be heard is purely the compressor. The compressor kicks in after 30 seconds or so.

[coopso]

I've installed the fan, was a pain because the adaptor whilst clearly marked as 92->120 does not fit a 120mm fan! Anyway some judicious use of zip ties has resulted in the fan successfully being installed. For now it is oriented the same way as the original was (i.e. is blowing air out of the unit). Seems to be fine for now, I may switch it round later (I need more zip ties!).


So the fan is nice and quiet. Thanks for the advice,


But the noise from the compressor itself is really intrusive, especially when it first comes on. I'm guessing I have to live with this, but here's a video in case anyone has any bright ideas. The fan is disconnected so the noise that can be heard is purely the compressor. The compressor kicks in after 30 seconds or so of the video.

[Sternwake]

Faulty compressor.

Sounds horrid.
Warranty...?

[coopso]

Originally Posted by Sternwake

Faulty compressor.

Sounds horrid.
Warranty...?

Unfortunately not, I bought it second hand.

[Uncle Bob]

Originally Posted by coopso

Unfortunately not, I bought it second hand.

Send a message to Richard Kollman, the refrig guru, I am sure he will help.

[Richard Kollmann]

Originally Posted by Uncle Bob

Send a message to Richard Kollman, the refrig guru, I am sure he will help.

That is really three questions, how to reduce noise level of condenser fan? And what fan Cfm capacity is going to be efficient? And is a variable speed fan efficient?

Excessive condenser fan noise results from its motor armature bearings worn are they are not good sealed ball bearings. Other problems are blade tip clearance and speed, fan blade aerodynamics resident frequency balance. Not to mention mounting support for fan.
At one time I would have purchase the most expensive fan with a matching frame to old fan. Today I would look for a fan with a noise level ratting of 50db or less this is equal to an older Florescent light noise level.

These 12 volt fans are rated in Cubic feet of air per minute (Cfm) Selecting the correct fan Cfm will depend on disposing of heat removed from refrigerated area as well as the electromotive heat produced by compressor so each refrigeration unit may have a different condenser and fan size. Source of condenser cooling medium air and its temperature will affect Cfm capacity of fan selected. The principles of removing refrigeration heat in a boat is draw condenser cooling air from low in boat and exit heat high in boat cabin. The heat produced by a small Danfoss compressor is much the same as heat from one person. Manufactures like Danfoss do not size condenser fan Cfm but do provide condenser gas temperature typically 90 C from that the system design engineer selects fan capacity normally based on standard day temperature. By now I hope you understand mobile refrigeration is not the same as your mothers kitchen refrigerator. In systems powered by Danfoss BD compressors you will find fans ratted at from 25 Cfm to 180 Cfm and even no fans with static air condensers.
I have a rule of thumb I believe in, fan and condensing unit combined should deliver a temperature of cooled liquid refrigerant to refrigerant control device Cap tube or TXV of around 115 degrees F when frost starts forming on evaporator.

Variable speed condense fans are good idea but must be controlled by either liquid high pressure or liquid line temperature. There is a simple solution covered under FANS on my web site intended to improve condenser cooling by adding a second condenser cooling fan automatically controlled by a $10 adjustable snap action switch attached to condenser or compressor. When manufactures fan cooling is not enough the heat of compressor or if condenser exceed normal temperatures second fan will run.

There have in the past quality efficient fans mentioned here that are quite, energy efficient , and have a life span much greater than a fan that might come with the unit. A limiting factor for a better fan may be limited by fan installation compatibility. For any fan to be efficient all its volume of air must be shrouded in a way all of it must pass through condenser coils and not return to pass through a second time.

[Sternwake]

I always wondered if Overcooling of the condenser, with too much fan, was possible, in mild ambient temperatures.

My fridge compartment is adjoined to another cabinet. This cabinet now has my original 2013 era Noctua NF-f12 exhausting both.

I put the Noctua A12x15, (only 15mm thick) on my condenser a few years back and at that point moved the nf-f12 to adjacent cabinet.
The extra 10mm space behind the fan compared to 25mm thick fans, it was hoped, would help the degree of flow through the fan and reduce noise further. This was successful in the noise department. I did not take before and after duty cycle data with this second fan switch.

The A12x15 draws about double the amperage of the NF-f12,but which is still less than the sleeve bearing fan provided with the fridge.

This 0.05amp NF-f12 Noctua fan, and their non industrial versions, come with one or two 'noise reducing adapters', which contain a resistor inline on the cable which slows the impeller rpm, reduces noise and amp draw.

This 0.05 amp load, with no resistor cable inline, is insignificant enough, that I just run it 24/7, rather than have it switch it with the compressor.

So This second fan now draws air, through my condenser, then across my compressor and compressor controller, even when the fridge compressor is not running and the A12x15 is pushing air into the condenser.
In winter I run the slowest 'noise reducing cable' adapter, in summer I take it off for the full 1500 rpm@12vdc.

My system works awesome, but I wonder if I am shortening the Fridge ( VF c51is) lifespan by having ventilation across condenser and compressor even when the compressor is not running. the ~15 minutes off, but with 50cfm of air being drawn around the compressor, likely has it swinging through a wider temp range, even if it never gets quite as hot as it would without the second fan always pulling air through condenser/across compressor.

coopso,

Your 92 to 120mm adapter likely moves the fan far enough away from the condenser fins that it does not cause the impeller blades to stall, which makes the fan sound like it is spinning faster, as it becomes louder when it can't efficiently scavenge air from behind it.

My opinion is that mounting a computer fan directly to pull air through a radiator/ condenser, with little to no space behind the blades and fins, is asinine design.

I've not used such an adapter (92 to 120mm), but I experiment with all sorts of computer fans all the time. They ALL are quieter when there is no restriction immediately behind the impeller, and ALL are quieter, and move more air, when pushing into a restriction( condenser/radiator) rather than pulling it through.

If a fan grille/ finger guard has to be used, moving it just 5mm farther away from the blades yields surprising improvements in noise and airflow, and mo distance is mo Betta, upto a point.

The closer the restriction is to the spinning fan blade, the louder it gets and the worse it performs, but pushing into a restriction is always much better than pulling, on the dozens of fans I have experimented with. The only difference is the degree, but it is always significant.

My 2013 era Vitrifrigo c51is came with a sleeve bearing fan, rated for 72 cfm but did not list a static pressure rating, iirc.

When I first got it, i was running it, using it normally, but outside the cabinet which I had to modify, as it was built for a norcold De-0040, which is slightly shorter and exhausted out the top faceplate. When the NF-f12( ~53 cfm, but high static pressure rating) arrived, I took duty cycle data, before removing the VF provided fan and then seeing the On/OFF cycle times when I installed Noctua NF-f12, orienting it to blow into the condenser.

It went from ~ 5.5 minutes on and ~15 minutes off to ~4.75 minutes on to ~15 minutes off, and was quieter, and the fan itself drew half what the fan VF provided with the fridge.

The VF c51is is a front loading 51 cubic liter( 1.8 cubic foot) fridge with the cooling unit on the top back of the unit. I made a cooling unit 'tunnel' from the failed Norcold's door skin to not only protect the cooling unit from installation/ removal stress/ impact, but to also insure the fan's full flow went not only through the condenser, but also across compressor and compressor controller, and then into the adjacent cabinet, with no possibility of being recycled through condenser.
I also lined this 'tunnel' with some Butyl rubber roof flashing, with Nashua Flexfix 555 tape covering the sticky edges. This helps dampen the noise of the compressor, somewhat.

The danfoss/secop bd35f compressor is so much quieter than my Sawafuji powered Norcold was, that this extra sound dampening was not needed.

The 72 CFM sleeve bearing fan provided with the VF c51is was louder than the compressor.
The Noctua NF-f12 mounted to condenser, to pull air through condenser was louder than compressor.
The Noctua NF-12 mounted to opposite side of the condenser, to push Air through it, was significantly quieter than the compressor.
The Noctua A12x15 mounted push where the NF-f12 did for 5+ years previously, was quieter.

My 2013 era danfoss/secop bd35f makes a clunk when the compressor first turns on, but after that, I cannot hear it. I only rarely notice the clunk nowadays, when all else is very quiet.

Your Video sounds like a horrible metal on metal sound, like some moving part within the compressor is touching that which it should not.

Is this noise coming from the compressor body itself, or from some other part of the portable/chest style cooler?
Can you change the noise intensity by tilting the unit, or putting a finger here or there on surrounding components?

You say the noise is especially bad when the compressor first fires up. Does this duration of noise, before getting quieter, change with ambient temperature?

If that horrid metal on metal sound is emanating from the bd 35f compressor body itself, I would not expect it to live a long life, and would expend little to no more energy in trying to make it quieter, unless tinkering is just in your nature.

If tinkering is, and the compressor noise intolerable, while that clocks ticks toward potential(likely?)premature failure, and...

With your fridge being a portable, you always have to be aware to not cover the cooling unit's vents. One could build a spot for it that can perhaps dampen the sound, but still allow, or even perhaps enhance, ventilation through the cooling unit.

Dual ball bearing computer fans are awesome, much better than sleeve bearing fans, though when new and still lubed well, the sleeve bearing is usually quieter for the same sub 1800 rpm.

The hydrodynamic/ Maglev bearing types of fans are the quietest, and the longest lived, at least warranty wise.

in 2013 I asked Noctua about compressor vibrations and their 'SSO' bearing and they said it should not be an issue. It was/ is not.

I've used an accellerometer app on my phone to greatly reduce noise and vibration from some high rpm Computer fans that are imperfectly balanced, but these are not fridge applications, and I've not experimented with the Noctuas in this regard. The IPPC 3krpm noctuas could have likely benefitted, before they all failed, as I recall feeling then vibrate at high rpms.

While My condenser fan is now only 15mm thick, and the previous fans were 25mm thick, there are 38mm thick fans. Pretty much overkill for a fridge condenser in my opinion, but the thicker the fan the more static pressure and CFM it can generate for the same rpm.

CFM ratings of fans are in open air. No restrictions. I am told they measure the velocity of the air exiting the fan and do some math with fan diameter to come up with the rating they post as opposed to actually physically measuring the volume of air moved.

If one plays with a computer fan, one with 4 hub supports, they will likely find 4 hotspots of flow, exiting fan at wide angles. If this hotspot velocity is what is measure, and they do some math with fan diameter to come up with the CFM, then that cfm rating is wildly inaccurate/misleading in my opinion.

The static pressure rating of a fan, when mounted close to a restriction, is a much better figure, in my opinion.

The Noctua NF-f12 has only a 53 cfm rating, but in static pressure ratings, outperforms most other 120x25mm fans with a 50% higher CFM rating. The computer nerds loved the NF-f12 for its ability to keep their motherboards cooler for significantly less noise.

[coopso]

Originally Posted by Sternwake

Your Video sounds like a horrible metal on metal sound, like some moving part within the compressor is touching that which it should not.

Is this noise coming from the compressor body itself, or from some other part of the portable/chest style cooler?
Can you change the noise intensity by tilting the unit, or putting a finger here or there on surrounding components?

You say the noise is especially bad when the compressor first fires up. Does this duration of noise, before getting quieter, change with ambient temperature?

If that horrid metal on metal sound is emanating from the bd 35f compressor body itself, I would not expect it to live a long life, and would expend little to no more energy in trying to make it quieter, unless tinkering is just in your nature.

If tinkering is, and the compressor noise intolerable, while that clocks ticks toward potential(likely?)premature failure, and...

With your fridge being a portable, you always have to be aware to not cover the cooling unit's vents. One could build a spot for it that can perhaps dampen the sound, but still allow, or even perhaps enhance, ventilation through the cooling unit.

Thanks for your reply, Sternwake.


This seems to be a "like it or lump it" situation. I guess I know why the seller decided to get rid.


The noise does seem to be coming from the compressor, although it is difficult to tell. Certainly the sound doesn't change if I apply pressure to various parts of its body, or any of the tubes, cooling fins etc etc.


Thanks so much for your advice, folks. I'll see if I can live with the noise or not and if no I'll replace it. Has been fun tinkering and I'll repeat the fan upgrade if I get a new fridge.

[Sternwake]

One of these, or similar, is always good to have:

Lisle 52500 Mechanic's Stethoscope

A piece of hose between and ear and suspected noise source can also help eliminate 'seems'.

Some do the same with a screwdriver.