# Computer Fan - Really Loud?



## pokolbinguy (19/10/07)

I went and bought a computer fan today.... cost me bloody $29.95.... but anyway it is a 12V 120mm ball bearing fan and is running off a nokia phone charger (12 V 780mA) and the fan is 12V 380mA. 

Now the fan is hooked up and inside the freezer however it is rather loud, even from when the lid is shut. should I:

1. buy a smaller fan
2. use a lower rated power supply
3. ignore it... I dont like this idea... others in the house will complain.


Cheers Pok


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## PostModern (19/10/07)

Lower the voltage. At 7V it should be almost silent and move as much air as a 80mm fan at 12V


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## Sammus (19/10/07)

wow, for $30 you must of got some sort of performance cooling solution. I use a 12V 80mm fan that I got for $4 brand new. Granted it isnt ball bearing but its almost silent.


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## pokolbinguy (19/10/07)

PostModern said:


> Lower the voltage. At 7V it should be almost silent and move as much air as a 80mm fan at 12V




OK ... will have to search for another charger ... damn means I have to pull it apart and re-solder.



Sammus said:


> wow, for $30 you must of got some sort of performance cooling solution. I use a 12V 80mm fan that I got for $4 brand new. Granted it isnt ball bearing but its almost silent.




man I got ripped off...where did you get yours sammus?

Pok


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## sanders4_ (19/10/07)

I sourced my computer fans from a computer fair in ACT, its one of those fairs that travel all over the place so finding one shouldn't be hard, 
try here http://www.computermarkets.com/ 
or here http://www.computerfairs.com.au/index.php?...t&Itemid=38


Otherwise, Jaycar or Dicksmith.

I posted on this thread HERE talking about how to wire up computer fans from 12V. The smaller ones pictured in that thread (80mm i think) running @ 12V should be almost silent. 

Are the blades running free, i.e. the fan isn't resting on a wire rack in the freezer is it? thats the only time mine have made noise, but i just turn them up the other way, and they are happy.


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## pokolbinguy (19/10/07)

sanders4_ said:


> Are the blades running free, i.e. the fan isn't resting on a wire rack in the freezer is it? thats the only time mine have made noise, but i just turn them up the other way, and they are happy.



The fan was sitting on top of a fee glasses just to see how it went... moved it and it is heaps quieter now.

Now next question.... should I let it run all the time???

Cheers, Pok


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## Simon W (19/10/07)

Continuous operation won't bother it. Should last years before the bearings go.


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## grinder (19/10/07)

Excuse my ingnorance, but what are the fans used for??


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## Sammus (19/10/07)

pokolbinguy said:


> ...where did you get yours sammus?



I got a box of 10 for $40 at a computer fair. I can't imagine what happened to them, I dont even have a desktop computer and I only have one left :huh:

That kind of raises the question of why I bought them in the first place lol... I havent made 9 stir plates thats for sure


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## Sammus (19/10/07)

grinder said:


> Excuse my ingnorance, but what are the fans used for??



If you circulate the air inside the fridge/freezer it eliminates thermal layering inside. Only really a problem in something like a serving/fermenting fridge that can go for a long time unopened, so the air inside isnt disturbed at all.


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## pokolbinguy (19/10/07)

pokolbinguy said:


> The fan was sitting on top of a fee glasses just to see how it went... moved it and it is heaps quieter now.
> 
> Now next question.... should I let it run all the time???
> 
> Cheers, Pok




Ok so problem not solved... I found a couple of right angle brackets from my "Meachano" years and used them to fix the fan to the collar.... closed the lid, turned it on.... and still loud..... I think the smaller powered power supply is the go... will have to score one from somewhere.

Pok


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## alexbrand (19/10/07)

grinder said:


> Excuse my ingnorance, but what are the fans used for??



For forced convection. The air in the fridge gets moving and a better heat exchange between the cooling element and the goods (kegs, beer lines ...) is possible. So some problems (see first post in this thread) are solved.


Cheers,

Alex

EDIT: Okay, sammus was earlier


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## Juddy (19/10/07)

Yeh, I had the same noise problems! Ended up buying a 12v power supply from Jaycar that allows me to pick from12, 9, 6.5, 5, 4.5 and 3 volts! Also used some foam insulation between the fan mounting bracket and the collar/lid, to stop vibrations being transmitted. Fan now runs silently on the 6v setting, and I've got the ability to up the fan speed by simply flicking a switch!

Cheers
Juddy


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## pokolbinguy (19/10/07)

Juddy said:


> Yeh, I had the same noise problems! Ended up buying a 12v power supply from Jaycar that allows me to pick from12, 9, 6.5, 5, 4.5 and 3 volts! Also used some foam insulation between the fan mounting bracket and the collar/lid, to stop vibrations being transmitted. Fan now runs silently on the 6v setting, and I've got the ability to up the fan speed by simply flicking a switch!
> 
> Cheers
> Juddy



Now that sounds like a fantastic Idea.... would be able to crank it up if the freezer is getting a run for its money for a party etc... because I store my glasses in it ....

how much were they?

Pok


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## Juddy (19/10/07)

Hey Pok

From memory, I like you paid around $30 for my fan. But it is the ducted ball bearing type, if that makes sense. The power supply was a similar amount I think. Looks like a normal phone charger, just has a sliding switch on the back, and from memeory it came with a set of different plugs so you can use it on different phones.(they were of no use because I simply cut the cable!)
Cheers 
Juddy


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## pokolbinguy (19/10/07)

Juddy said:


> Hey Pok
> 
> From memory, I like you paid around $30 for my fan. But it is the ducted ball bearing type, if that makes sense. The power supply was a similar amount I think. Looks like a normal phone charger, just has a sliding switch on the back, and from memeory it came with a set of different plugs so you can use it on different phones.(they were of no use because I simply cut the cable!)
> Cheers
> Juddy




Cool, just found one on ebay for half that price...i think i will invest


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## tangent (19/10/07)

there's always free towers sitting on the side of the road.
maybe i should just grab one of those and rip out the power supply and the fans?


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## pokolbinguy (19/10/07)

tangent said:


> there's always free towers sitting on the side of the road.
> maybe i should just grab one of those and rip out the power supply and the fans?



Sounds like a good idea to me


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## paul (20/10/07)

Why not just wire the fan in so that it switches on and off with your compressor?

If you have the thermostat probe towards the top of the fridge it should in theory be the warmest place inside it. When the compressor cuts in so does the fan. This way it only works when its needed.


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## pokolbinguy (20/10/07)

paul said:


> Why not just wire the fan in so that it switches on and off with your compressor?
> 
> If you have the thermostat probe towards the top of the fridge it should in theory be the warmest place inside it. When the compressor cuts in so does the fan. This way it only works when its needed.



Sounds like it could work well... I might do this aswell. I got my hands on a 6.5V power supply and rigged up....much quieter now... now just to test the results :chug: 

Pok


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## alexbrand (20/10/07)

paul said:


> Why not just wire the fan in so that it switches on and off with your compressor?
> 
> If you have the thermostat probe towards the top of the fridge it should in theory be the warmest place inside it. When the compressor cuts in so does the fan. This way it only works when its needed.



IMHO it's needed all the time, as long as you want the temperature really 'controlled'. Imagine a bottom fermentic yeast close to the fridge's bottom. It might besome degrees colder than at the top where the thermostat probe is.
In the moment the compressor (and the fan) stops the cold air will fall down to the bottom. But the fridge keeps on cooling for a short period longer than it really runs. So why not let the fan run all the time and let it try to get a homogen tempered enviroment?

Alex


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## pokolbinguy (20/10/07)

I wonder what it costs to run a 6.5v fan at 500mA a day... would be interesting.... Anyone know how to work it out???

Pok


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## scrogster (20/10/07)

Nearly $30 for a computer fan? Don't you guys have annual hard rubbish collection out your way? Walking up and down the street stripping bits from abandoned computers should yield you a load of perfectly good computer fans for nix.


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## alexbrand (21/10/07)

pokolbinguy said:


> I wonder what it costs to run a 6.5v fan at 500mA a day... would be interesting.... Anyone know how to work it out???



Well, in theory your fan "needs" 78 watts per 24 hours (P = U * I --> 6.5V * 0,5A = 3,25VA --> 3,25VA * 24h = 78watts/day).
How much do you pay for 1 kWh?

Alex


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## pokolbinguy (21/10/07)

scrogster said:


> Nearly $30 for a computer fan? Don't you guys have annual hard rubbish collection out your way? Walking up and down the street stripping bits from abandoned computers should yield you a load of perfectly good computer fans for nix.




Not when you live in the country.

Pok


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## Ross (21/10/07)

For best performance, you want the fan running all the time; they cost bugger all to run. I'm amazed more guys don't rig them up in there regular fridges as well, they make a huge difference to getting a consistant temperature & speed up chilling of kegs, fermenters etc. I think it's Bonj who's got his rigged to switch off when the lid is opened; this would be the perfect senario, as you don't want to be disturbing the air when the lids open.

Cheers Ross


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## razz (21/10/07)

Just rigged up mine yesterday after seeing the interest in this thread. 12 volt 80mm fan from my old computer cost nothing and the guys at Jaycar in Frankston sold me a 12 volt 500 mah power pack for $16 and threw in a connector as well. Kegs are now happy at 3-5 degrees in freezer. I even managed to adjust the thermostat up a degree or two.


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## fixa (21/10/07)

I got a 240 volt fan from Dick Smith, can't remember how much, around $25 i think. Plugs straight into a timer, and i run it 10 mins on, 10 mins off. dunno why, i just do. It's not too noisy, not as noisy as the font pump anyway. Saves messing around with transformers though..


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## bindi (21/10/07)

I run a computer fan that cost bugger all and run it on 7.5v


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## Screwtop (21/10/07)

alexbrand said:


> Well, in theory your fan "needs" 78 watts per 24 hours (P = U * I --> 6.5V * 0,5A = 3,25VA --> 3,25VA * 24h = 78watts/day).
> How much do you pay for 1 kWh?
> 
> Alex


But the strain of pushing all that heavy cold air up to the top could make it as high as 80w/day. With domestic Tariff 20 here in Qld at 21.516c per kWh for the first 100kWh that could end up costing as much as 1.72c per day. Better shut off the fan.


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## newguy (21/10/07)

Screwtop said:


> With domestic Tariff 20 here in Qld at 21.516c per kWh for the first 100kWh that could end up costing as much as 1.72c per day. Better shut off the fan.



:huh: 

Folks around here are complaining about a kWh being increased to 8c from 7c. I can't imagine what would happen if we were charged 21c.


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## alexbrand (22/10/07)

Screwtop said:


> But the strain of pushing all that heavy cold air up to the top could make it as high as 80w/day. With domestic Tariff 20 here in Qld at 21.516c per kWh for the first 100kWh that could end up costing as much as 1.72c per day. Better shut off the fan.


Damn I forgot to calculate with these parameters! 
May be in the cold enviroment is also consumes more power because the air density is higher and so more power is needed to stirr the air?? Or a higher humidity? 

Screwtop, I think we really should shut off all out fans to prevent the earth from further global warming? BTW: if I look through the window at the moment I really would appreciate global warming... 

Alex


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## Fatgodzilla (22/10/07)

alexbrand said:


> Damn I forgot to calculate with these parameters!
> May be in the cold enviroment is also consumes more power because the air density is higher and so more power is needed to stirr the air?? Or a higher humidity?
> 
> Screwtop, I think we really should shut off all out fans to prevent the earth from further global warming? BTW: if I look through the window at the moment I really would appreciate global warming...
> ...



34 degrees Celcius here on the south coast of NSW - is this what they call global warming ................................................................................
................................................................................
........... wait, the southerly has just come in. 19 degrees celcius now - we have been saved. Thanks you Al Gore !!!!!!!!!!!!!!!!!!!


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## clintmo (28/10/07)

I ordered 4 of these fans from pccasegear.com which were on special at the time for $6 each... they are now $11. Incedently i have a camper and i was putting them in there for those hot nights over summer. They are very silent


> At the lowest speed setting this model operates at a silent 10dBA. At maximum speed the noise level is still barely audible at 24.5dBA, yet moves an impressive 34CFM.


. I have mine running straight off a 12v battery and they are really silent. If you are after a silent fan get the audible rating... after getting them i read the voltage / amps usage because power consumption is an issue for a campervan. 12v / 0.14 a = 1.73 W which is nothing really considering a light bulb is 75W (in some cases). Im also running a flouro in my van which is 18W, so basically i could run around 10 fans for the same amount of power as the flouro.

so instead of stopping that fan... turn off you lights 

EDIT "Arctic Cooling 92mm Fan AF9225 PWM" is the fan http://www.pccasegear.com/category320_1.htm
No affiliation yadayada just happy with a product


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## milpod (30/10/07)

Thought a few guys may be interested in cheap pc fans,fans
I installed one today,for the hot weather due,but my freezer is cycling more then once a hour now.

Before installation it cycled once a hour at most.

Am I missing something here?Seems to forcing cold out,as opposed to just circulating it.

Yes seals are airtight.Any ideas?

Cheers


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## newguy (30/10/07)

milpod said:


> Thought a few guys may be interested in cheap pc fans,fans
> I installed one today,for the hot weather due,but my freezer is cycling more then once a hour now.
> 
> Before installation it cycled once a hour at most.
> ...



Before the addition of the fan, the air in your freezer was stratifying - cold air at the bottom, warm air at the top. As time goes by, the layer of warm air grows thicker until it contacts the temperature sensor. That process used to take an hour. Now that you added a fan to stir the air, there is no stratification anymore. The compressor will thus cycle a little more frequently. Nothing to worry about.

The thing to consider is that with the fan installed, the entire contents of the freezer are at a consistent temperature and the temperature swings within it will be much less than without the fan.


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## SJW (31/10/07)

I have a spare phone charger that I want to hook up to a computer fan. The specs on the back say:

Input 240v/50Hz/21mA/5VA
Output: 3.7v/355mA/1.3VA

Would this be suitable to hook up to a 80m comp. fan?

Steve


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## Jye (31/10/07)

SJW said:


> I have a spare phone charger that I want to hook up to a computer fan. The specs on the back say:
> 
> Input 240v/50Hz/21mA/5VA
> Output: *3.7v*/355mA/1.3VA
> ...



The voltage is a bit low and probably wont even turn the fan and if it does the fan may not be fast enough to provide good circulation. Look for about 8-9v minimum.


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## kevnlis (31/10/07)

Most fans should have a voltage rating on them of the minimum voltage required to start the fan. 7v is pretty commonly required, but some can go with as little as 5v!


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## SJW (31/10/07)

I found another one and it says:

INPUT: AC100-240V/180mA. 50-60Hz
OUTPUT: DC 10V 740 mA

As u can see I dont do electronics

Steve


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## kevnlis (31/10/07)

Looks much better mate! Though that little sucker is gonna spin pretty fast and make a fair bit of noise with all that running through it!

You could rig a speed controller for it, or just buy a cheap 120mm fan.


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## Jye (31/10/07)

That will do fine.


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## SJW (1/11/07)

I have got on to a computer shop who can sell me a second hand computer fan. Now he said they they are either 5v or 12v as they are the two rails in a computer.
Now I have 2 AC adaptors a 9v 350mA and a 10v 740mA.
What combination should I go with?


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## Sammus (1/11/07)

SJW said:


> I have got on to a computer shop who can sell me a second hand computer fan. Now he said they they are either 5v or 12v as they are the two rails in a computer.
> Now I have 2 AC adaptors a 9v 350mA and a 10v 740mA.
> What combination should I go with?



Yeah theres 5V and 12V rails in a computer power supply, I aint never heard of no 5V computer fan though.
Get the 12V fan and use either adaptor - theyll both work fine.


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## SJW (1/11/07)

> Yeah theres 5V and 12V rails in a computer power supply, I aint never heard of no 5V computer fan though.
> Get the 12V fan and use either adaptor - theyll both work fine.


Thanks champ!


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## SJW (1/11/07)

Ok. I have found a computer shop that will sell me a new 80mm 12v case fan for $12. As I am only using a 10v output power supply would this fan size be big enough for a bar fridge with 2 corny's in it? And is it a good deal? I just like to buy new when I can. Rather than going to all the hassel of find an old box and tking the fan out, fitting it and then finding out its noisy or does not work.

Steve


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## kevnlis (1/11/07)

Yup, sounds like a good price to me. Should be plenty for a bar fridge!

As I mentioned before, the 120mm will be quieter, if that is important.


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## eric8 (1/11/07)

I have found a place that will sell an 80mm for $8. Now are these quiet or not so much? And is this going to be big enough for a 200l chest freezer?
eric


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## kevnlis (1/11/07)

eric8 said:


> I have found a place that will sell an 80mm for $8. Now are these quiet or not so much? And is this going to be big enough for a 200l chest freezer?
> eric



It is hard to say, every fan is different. But in general the larger the fan the quieter it will be. Also the larger fan will move more air, so for something like a 200L chest freezer a single 80mm may not move as much air as you would like?

I have a 210L upright brew fridge and I have 1x 120mm and 1x 80mm in it. Works great!


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## razz (1/11/07)

eric8 said:


> I have found a place that will sell an 80mm for $8. Now are these quiet or not so much? And is this going to be big enough for a 200l chest freezer?
> eric


Eric, I recently put an 80mm fan in my 300lt chesty and it works fine. Freezer is an ambient 3 degrees top to bottom.


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## eric8 (1/11/07)

razz said:


> Eric, I recently put an 80mm fan in my 300lt chesty and it works fine. Freezer is an ambient 3 degrees top to bottom.



Sweeeeeeet, that's what I wanted to hear.


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## Simon W (1/11/07)

> Yeah theres 5V and 12V rails in a computer power supply, I aint never heard of no 5V computer fan though.


Ditto. Never seen a 5v fan.
Thats not to say they don't exist, but they must be rare or just starting to come out.
I reckon the 5v fans are probably the small ones on CPU's and Graphics cards etc.

The one you want for your adaptors is a new PC case ventilation fan.
Or you can salvage one from an old PC's switchmode PSU, both are 12v.
Note that some salvaged PSU fans can have flogged out bearings from years of use and can be pretty noisy.


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## SJW (1/11/07)

Thanks boys, I got the 80mm 12v fan for $12. Its some kind of flash Hydrobearing/silent job that is good for 80,000 hours. Anyway, its in with my 10v power supply and I can say in all honesty that it is silent. I cant hear a thing. Its just sitting on top of my 2 kegs at the moment but it has slowed down the cycling of the fridge.
So thanks for the advice fellas.

Steve


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## milpod (2/11/07)

newguy said:


> Before the addition of the fan, the air in your freezer was stratifying - cold air at the bottom, warm air at the top. As time goes by, the layer of warm air grows thicker until it contacts the temperature sensor. That process used to take an hour. Now that you added a fan to stir the air, there is no stratification anymore. The compressor will thus cycle a little more frequently. Nothing to worry about.
> 
> The thing to consider is that with the fan installed, the entire contents of the freezer are at a consistent temperature and the temperature swings within it will be much less than without the fan.




Thanks newguy,I was under the impression that it was better for a freezer with a temp controller to only cycle about,once a hour.

However if a couple times a hour is cool,I'll run the fan

Cheers


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