theoretically, how much power can you draw from 12V rail on USB port?

Discussion in 'OT Technology' started by nietsni3, Feb 27, 2005.

  1. nietsni3

    nietsni3 Guest

    how many watts?
    thanks
     
  2. P07r0457

    P07r0457 New Member

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    you get 1.2A off of it to start. After it links up with the host, they can negotiate up to 6A. This is based off of your 12V assumption, given a 100mA starting value (USB spec) and a max-draw of 500mA (USB spec).
     
  3. nietsni3

    nietsni3 Guest

    i was thinking of modding my external enclosure (for 3.5" HDD) so taht it can draw power directly frm the USB port instead of an external power supply. how many watt does a 3.5" 7200rpm 200GB HDD usually needs? is it possuble to combine multiple USB ports together to rally a greater output power?
     
  4. P07r0457

    P07r0457 New Member

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    definitely a BAD idea. There are already enclosures that use 2 USB ports to run a notebook hdd... but that requires more than 1 port, and a low-power notebook HDD... Not a desktop drive.
     
  5. DAN513

    DAN513 OT Supporter

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    Usually on a 7200rpm drive you're looking at 25-30 watts.
     

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