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Question: How to power DC fans?

post #1 of 4
Thread Starter 
Basically, I have 2-3 80mm DC (rated for 12v and .6A) fans that I wish to use to cool my Jtag (xenon xbox) (don't question the reason, the reason is obviously there for those knowledgeable in the area)

Now, the simple answer would be to buy a 10$ psu... but.. those are on the big side.. and more money than I want to spend.

I want to try to use one of my many laptop power supplies, or power supplies that I have for random things (like old printers ect).

Most of my laptop power supplies are 15-20v and rated for 3-3.5A
I am assuming this voltage would kill my fans?

I have this random psu that is rated for 9v and 3.0A.
Would this one work?

I plan to splice the 2 fans onto the main cord in 2 different locations. One near the end and the other at the end (chopping off the existing connector)

Thanks for any advice.
    
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post #2 of 4
Undervolting fans is generally okay and many people do it to lower the rpm and thus noise. The 9V one would probably be fine if you don't mind the slower speed.

Do note that the startup voltage of fans depends on the model. i.e. the fan does not turn on until it gets X volts or more. Check the specs of your fans. If the required startup voltage is close to 9V or higher, you'll need to figure something else out.
post #3 of 4
Buy a wall wart (unregulated PSU).

These are the same things that power small devices and charge cell phones.

12v, 1A for $3.32 shipped:
http://cgi.ebay.com/AC-100V-240V-Con...item2c5d885e6b
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post #4 of 4
You should be able to run the fans at 9v. However if you want the full 12v then I think you should be able to use a voltage regulator to bring the 15-20v down to 12v.
     
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CPUMotherboardGraphicsRAM
Intel Core i5 2500k @ 4ghz Asus P8P67 pro Gigabyte GTX780 12GB Corsair RAM (2/3 vengance, 1/3 XMS3) 
Hard DriveHard DriveHard DriveOptical Drive
500gb Spinpoint f3 Samsung 840 EVO 120gb Seagate 7200.14 2tb Samsung dvd+-rw 
CoolingOSMonitorMonitor
Noctua NH-D14 Windows 7 ultimate x64 LG 24MP55 x2 LG 32LD450 
KeyboardPowerCaseMouse
Dell thing. Corsair TX650 Coolermaster cm690 Logitech G500 
Mouse PadAudioAudio
none Xonar DG and logitech X-540 Beyer DT770 PRO 
CPUMotherboardGraphicsRAM
AMD A6-4455m 2.1ghz Dual Covered in tea stains Radeon 7500G 6GB 
Hard DriveOptical DriveCoolingOS
SSD soon None Inadequate Win7 of course 
MonitorKeyboardCase
It's awful A bit meh, Bodged hinge repair (Nut and bolt through back ... 
CPUMotherboardGraphicsRAM
Celeron M 360 1.4ghz Packard bell easynote (lynx banias) Intel 855gm 768mb 
Hard DriveOptical DriveOSMonitor
50gb seagate Cd dvd combi XP sp3 15 
KeyboardPowerCaseMouse
one with buttons Brick It has one It has leds 
Mouse Pad
my lap or the chair 
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