The Notebook Review forums were hosted by TechTarget, who shut down them down on January 31, 2022. This static read-only archive was pulled by NBR forum users between January 20 and January 31, 2022, in an effort to make sure that the valuable technical information that had been posted on the forums is preserved. For current discussions, many NBR forum users moved over to NotebookTalk.net after the shutdown.
Problems? See this thread at archive.org.

    question about powering fans by usb

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by tornbacchus, Sep 17, 2008.

  1. tornbacchus

    tornbacchus GO leafs.. Wait, Nevermid

    Reputations:
    265
    Messages:
    1,080
    Likes Received:
    0
    Trophy Points:
    55
    ok well im making a notebook cooler. i have 2 - 12v fans from tiger direct.

    i was going to have both powered by usb but have had advice its too much power.

    so would that mean that the fans are running slower than they should be?\
    i wired the fans to a usb wire and plugged it into the wall, with a usb converter. would this make the fans downclock and run slower?

    is there a way i can get the fans to run faster?
     
    tornbacchus, Sep 17, 2008
    #1
  2. Fayes

    Fayes Newbie

    Reputations:
    0
    Messages:
    7
    Likes Received:
    0
    Trophy Points:
    5
    Dont think the usb port got the power to get it started.
     
    Fayes, Sep 17, 2008
    #2
  3. tornbacchus

    tornbacchus GO leafs.. Wait, Nevermid

    Reputations:
    265
    Messages:
    1,080
    Likes Received:
    0
    Trophy Points:
    55
    it actually does run both fans when plugged into the computer and wall usb.
     
    tornbacchus, Sep 17, 2008
    #3
  4. tornbacchus

    tornbacchus GO leafs.. Wait, Nevermid

    Reputations:
    265
    Messages:
    1,080
    Likes Received:
    0
    Trophy Points:
    55
    anyone? i tried using a plug, but it was too much power, it blew the fans so i have to buy 2 new fans :( im probably just going to use a usb unless someone can tell me a better way
     
    tornbacchus, Sep 18, 2008
    #4
  5. K-TRON

    K-TRON Hi, I'm Jimmy Diesel ^_^

    Reputations:
    4,412
    Messages:
    8,077
    Likes Received:
    2
    Trophy Points:
    205
    USB provides 5 volts of power, so if your fans are 12volts, they will not spin very fast. You would need volatge rectifiers to bump the 5volts up to 12volts for the fans to operate at nomal speed. However using voltage rectifiers are inefficient and will cause more than double the current to keep the fans spinning. Since the usb rail only outputs 1Amp, you may not be able to power a fan which states it needs 0.7Amps or more.

    Just use an external power source, or get AC fans, which you can just plug into the wall.

    What fans are they, and what is the power draw on each of them?

    K-TRON
     
    K-TRON, Sep 19, 2008
    #5
  6. FusiveResonance

    FusiveResonance Notebook Evangelist

    Reputations:
    143
    Messages:
    421
    Likes Received:
    0
    Trophy Points:
    30
    Perhaps use multiple USB ports, but you'd still need a voltage rectifier and circuits knowledge.
     
    FusiveResonance, Sep 19, 2008
    #6