Wiring a PC fan to an AC adaptor - Rookie questions

apt220 · 03/11/2011, 04:42 PM

Can I run a 12V 0.15A PC fan wired to an AC adaptor rated at 12V 3A?

Also if I do, will the fan run at 0.15A, or will the it run at 3A?

reefermad619 · 03/11/2011, 05:31 PM

Yes you can. The fan will only pull .15amp on the 3amp plug.

apt220 · 03/11/2011, 05:38 PM

Great thank you.

MTWiley · 03/11/2011, 05:42 PM

My understanding is that the fan will only use as many amps as it needs and that when selecting a power supply you only need to make sure that it's not more voltage than your device needs and that it's at least as many amps as you need.

DownwardDawg · 03/11/2011, 05:56 PM

Quote:

Originally Posted by MTWiley

My understanding is that the fan will only use as many amps as it needs and that when selecting a power supply you only need to make sure that it's not more voltage than your device needs and that it's at least as many amps as you need.

And you would be correct!!!

Harry_Y · 03/11/2011, 10:26 PM

You only draw as much current as you need.

ludnix · 03/11/2011, 11:35 PM

Do make sure your adapters are 12VDC, I have seen quite a few 12VAC adapters laying around, presumably just to get my hopes up and then crush them.

apt220 · 03/12/2011, 12:55 AM

Great, will do

Musbtr1pin · 03/12/2011, 10:11 AM

voltage isnt really the determining factor here.. It's amperage.. It's AMPS that push the voltage through the wire.. Higher the amps, the more power you will have. IE 240 V at 100 AMPS puts out 24000 VA... Where a 120 V 200 Amp, puts out 24000 VA as well.. I have used these types of circuits before at work.. "Electrical Maintenance" blah...

Was thinking about hooking up a Allen Bradley PLC system to my tank, so I can micromanage, and basically leave the maintenance to the birds!

Not to sure about pc fans... But you might want to make sure that the fan is not a DC that you are trying to convert using an AC adapter... You will smoke it... period... Hope this helps

Bananafish · 03/12/2011, 10:59 AM

Everything inside PCs run on DC, and you can't use them unless you get a rectifier (to convert AC to DC). You can get a rectifier (or an AC fan) at Radio Shack.

phasezero · 03/12/2011, 12:21 PM

Quote:

Originally Posted by Musbtr1pin

voltage isnt really the determining factor here.. It's amperage.. It's AMPS that push the voltage through the wire.. Higher the amps, the more power you will have. IE 240 V at 100 AMPS puts out 24000 VA... Where a 120 V 200 Amp, puts out 24000 VA as well.. I have used these types of circuits before at work.. "Electrical Maintenance" blah...

Was thinking about hooking up a Allen Bradley PLC system to my tank, so I can micromanage, and basically leave the maintenance to the birds!

Not to sure about pc fans... But you might want to make sure that the fan is not a DC that you are trying to convert using an AC adapter... You will smoke it... period... Hope this helps

I think you have it reversed, i'm pretty sure voltage is the force, or the potential difference between two different points.

sfsuphysics · 03/12/2011, 12:40 PM

Also note that 12V plug might be 12 volts when loaded with components that it was made for, wouldn't suprise me if you read 15V on it with a voltmeter, so your fan might run a bit on the fast/noisy side.

And what I used to teach my students, compare electricity to water, current is the amount of water that's moving, voltage is the pressure difference that allows that water to flow.

Bananafish · 03/13/2011, 12:43 PM

Quote:

Originally Posted by phasezero

I think you have it reversed, i'm pretty sure voltage is the force, or the potential difference between two different points.

Voltage is the potential difference, yes. Meaning, the difference in charge between two contacts. House current has a potential of 110 volts between the hot and neutral sides of the outlet. Amperage is the force of the current, which is independent of the voltage. At standard house current a 40 Watt bulb uses 0.36 amps. The same bulb in a 220volt circuit will only use 0.18 amps because it will not exceed 40 Watts. Similarly, at 55 volts (oh, where would that be?) this bulb would use 0.72 amps.

Harry_Y · 03/13/2011, 04:54 PM

Here is something to think about.

I'm not sure what you are trying to cool but
usually when you run a 12 v fan at 12v it is noisy.

I put four 3" 12vdc fans on my light fixture, when I ran them at 12 v they were louder
than I likes and they actually cooled the bulbs too much (the bulbs actually dimmed).

I went to radio shack and pickuped a selectable output powers cube

Enercell™ Universal 1000mA AC Adapter
Model: 273-316
Catalog #: 273-316
$19.99

At the 7.5 v setting the bulbs do not over cool and the fans are much quieter

apt220 · 03/13/2011, 10:22 PM

I have an ATI Powermodule and I've noticed that increasing the voltage increases noise. But doesn't decible rating of the fan matter more? I have these 20db fans from China that are running at 12V and they are pretty quite.

FYI I'm cooling some LEDs with this fan.

Harry_Y · 03/13/2011, 11:40 PM

Quote:

Originally Posted by apt220

I have an ATI Powermodule and I've noticed that increasing the voltage increases noise. But doesn't decible rating of the fan matter more? I have these 20db fans from China that are running at 12V and they are pretty quite.

FYI I'm cooling some LEDs with this fan.

DB is the noise level of the fan

CFM (cubic feet a minute) is the volume of air they move.

I tend to buy a fan that moves More air than I need then
dial it back it cuts the noise and still gives desired air flow.

OregonReefer · 03/13/2011, 11:49 PM

If you're looking for an easy to use power supply for PC fans this one is pretty turnkey

http://www.crazypc.com/products/7410.html

apt220 · 03/16/2011, 09:28 PM

Thanks. ebay has some pretty cheap alternatives as well.

King_Richard · 03/17/2011, 10:14 AM

Or, I have two fans currently running on the tank. One fan is using a USB charger that I spliced off the ends of one side and wired it to the fan.

The other fan is running off of a 10v pwr supply that's used for moonlights that I bought along time ago, they're two of them in the sump and I also spliced in a fan on them I've placed in the sump area.

Any extra USB or Phone chargers that you have could run a fan on them, alot of people have extras of these so it might be worth a shot if you do.

DustinB · 03/17/2011, 10:33 AM

Quote:

Originally Posted by sfsuphysics

Also note that 12V plug might be 12 volts when loaded with components that it was made for, wouldn't suprise me if you read 15V on it with a voltmeter, so your fan might run a bit on the fast/noisy side.

And what I used to teach my students, compare electricity to water, current is the amount of water that's moving, voltage is the pressure difference that allows that water to flow.

This!

Depending on the brand and how it was made I would be surprised if you saw upwards of 17+ volts on a wall wart rated at 3A.

If your fans are rated at 12V .15A I would be looking for a truly regulated wall wart or something in the 8-9v at around 300-500mA range. Should give you around 11-12v at 150mA.

As others have stated, DC only pulls the amount of current it needs. The problem with these wall plugs is in order to make them cheap, they wire them in a way that under a certain current draw they should be outputting a given voltage. More current draw results in less voltage and possibly more heat/failure, less current draw results in higher voltage.

03/11/2011, 04:42 PM	#1
apt220 Member Join Date: Dec 2001 Location: Chula Vista, CA Posts: 1,305	Wiring a PC fan to an AC adaptor - Rookie questions Can I run a 12V 0.15A PC fan wired to an AC adaptor rated at 12V 3A? Also if I do, will the fan run at 0.15A, or will the it run at 3A?

03/11/2011, 05:31 PM	#2
reefermad619 Registered Member Join Date: Dec 2009 Location: The Salty D! Sandy let go of my eggo! Posts: 1,962	Yes you can. The fan will only pull .15amp on the 3amp plug. __________________ Fish tanks and Chevys... And my cousin's Datsun too. Some call it paranoid. I call it prepared. You have more post than I do... You MUST be right then!

03/11/2011, 10:26 PM	#6
Harry_Y Registered Member Join Date: Jan 2011 Location: NY Posts: 454	You only draw as much current as you need. __________________ . 180 Gallon Reef with Basement Sump, Apex Controller, Hamilton Cebu Sun Light, Lifereef Skimmer and Calcium Reactor.

03/11/2011, 11:35 PM	#7
ludnix Registered Member Join Date: May 2007 Location: California Posts: 3,031	Do make sure your adapters are 12VDC, I have seen quite a few 12VAC adapters laying around, presumably just to get my hopes up and then crush them. __________________ -Eric Sutter Current Tank Info: 14g Biocube

03/12/2011, 10:59 AM	#10
Bananafish Registered Member Join Date: Jan 2011 Location: Western Suffolk, New York Posts: 311	Everything inside PCs run on DC, and you can't use them unless you get a rectifier (to convert AC to DC). You can get a rectifier (or an AC fan) at Radio Shack. __________________ ~ Sal ~ Current Tank Info: It's 3,000 gallons smaller than I wish it could be

03/11/2011, 05:38 PM	#3
apt220 Member Join Date: Dec 2001 Location: Chula Vista, CA Posts: 1,305	Great thank you.

03/11/2011, 05:42 PM	#4
MTWiley Registered Member Join Date: Jan 2011 Location: Kansas City Metro Posts: 273	My understanding is that the fan will only use as many amps as it needs and that when selecting a power supply you only need to make sure that it's not more voltage than your device needs and that it's at least as many amps as you need.

03/12/2011, 12:55 AM	#8
apt220 Member Join Date: Dec 2001 Location: Chula Vista, CA Posts: 1,305	Great, will do

03/12/2011, 10:11 AM	#9
Musbtr1pin Registered Member Join Date: Feb 2011 Location: Portland, Oregon Posts: 293	voltage isnt really the determining factor here.. It's amperage.. It's AMPS that push the voltage through the wire.. Higher the amps, the more power you will have. IE 240 V at 100 AMPS puts out 24000 VA... Where a 120 V 200 Amp, puts out 24000 VA as well.. I have used these types of circuits before at work.. "Electrical Maintenance" blah... Was thinking about hooking up a Allen Bradley PLC system to my tank, so I can micromanage, and basically leave the maintenance to the birds! Not to sure about pc fans... But you might want to make sure that the fan is not a DC that you are trying to convert using an AC adapter... You will smoke it... period... Hope this helps

03/12/2011, 12:40 PM	#12
sfsuphysics Registered Member Join Date: Jan 2004 Location: San Francisco Posts: 9,103	Also note that 12V plug might be 12 volts when loaded with components that it was made for, wouldn't suprise me if you read 15V on it with a voltmeter, so your fan might run a bit on the fast/noisy side. And what I used to teach my students, compare electricity to water, current is the amount of water that's moving, voltage is the pressure difference that allows that water to flow. __________________ Mike

03/13/2011, 04:54 PM	#14
Harry_Y Registered Member Join Date: Jan 2011 Location: NY Posts: 454	Here is something to think about. I'm not sure what you are trying to cool but usually when you run a 12 v fan at 12v it is noisy. I put four 3" 12vdc fans on my light fixture, when I ran them at 12 v they were louder than I likes and they actually cooled the bulbs too much (the bulbs actually dimmed). I went to radio shack and pickuped a selectable output powers cube Enercell™ Universal 1000mA AC Adapter Model: 273-316 Catalog #: 273-316 $19.99 At the 7.5 v setting the bulbs do not over cool and the fans are much quieter __________________ . 180 Gallon Reef with Basement Sump, Apex Controller, Hamilton Cebu Sun Light, Lifereef Skimmer and Calcium Reactor.

03/13/2011, 10:22 PM	#15
apt220 Member Join Date: Dec 2001 Location: Chula Vista, CA Posts: 1,305	I have an ATI Powermodule and I've noticed that increasing the voltage increases noise. But doesn't decible rating of the fan matter more? I have these 20db fans from China that are running at 12V and they are pretty quite. FYI I'm cooling some LEDs with this fan.

03/13/2011, 11:49 PM	#17
OregonReefer Registered Member Join Date: Dec 2010 Location: Portland, OR Posts: 629	If you're looking for an easy to use power supply for PC fans this one is pretty turnkey http://www.crazypc.com/products/7410.html __________________ 120g drilled, 30G sump, 20g Fuge, RO NWB200 Skimmer, Glass Holes Overflow, mag 12.0 return, Reeflo Dart closed loop, 6-bulb Sunlight Tek

03/16/2011, 09:28 PM	#18
apt220 Member Join Date: Dec 2001 Location: Chula Vista, CA Posts: 1,305	Thanks. ebay has some pretty cheap alternatives as well.

03/17/2011, 10:14 AM	#19
King_Richard Registered Member Join Date: Jun 2010 Location: Pensacola FL Posts: 235	Or, I have two fans currently running on the tank. One fan is using a USB charger that I spliced off the ends of one side and wired it to the fan. The other fan is running off of a 10v pwr supply that's used for moonlights that I bought along time ago, they're two of them in the sump and I also spliced in a fan on them I've placed in the sump area. Any extra USB or Phone chargers that you have could run a fan on them, alot of people have extras of these so it might be worth a shot if you do. __________________ "I know where I'm going, just don't know how I'm getting there" 60g Cube>50g Sump\Cube Algae Scrubber:) 6" DSB:) Live Rock:) Caulerpa :) and nothing else!

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Wiring PC Fans off 12v power supply in parallel	ReefEnabler	Do It Yourself	7	04/09/2009 12:42 AM
how do i wire pc fan to adaptor	heyfredyourhat	Lighting, Filtration & Other Equipment	5	09/16/2007 08:37 PM
question about power adaptor for pc fans	sjm1978	Arizona - Fish & Reef Aquarium Group (FRAG)	15	10/19/2006 06:24 PM
AC Adapter & PC Fans - Questions	NanoReefer53	Do It Yourself	5	01/16/2006 02:24 AM