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Avg 7" touchscreen power consumption, and general 5V-rail Q

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  • Avg 7" touchscreen power consumption, and general 5V-rail Q

    I know that most of these monitors are in the 7-10Watt range, and are powered from the PC's 12V rail... However, what is the average power consumption of the touchscreen itself, since it gets its power from the USB port.

    I'm looking at the M1-ATX as my primary choice right now for the PSU on my car-pc, but I'm wondering if it will be enough to power the following items:

    EPIA MII-12000 mainboard
    slimline CD-RW/DVD drive (Toshiba TS-L462) (unknown Amperage, 5V rail)
    40Gb laptop drive (0.6A on the 5V rail)
    7cm cooling fan
    7" LCD screen
    USB1: LCD touchscreen (unknown, 5V rail)
    USB1: Rikaline 6010 GPS receiver (as far as I know, it's 100mA on the 5V rail)
    USB1: illuminated keyboard (Power consumption: DC5V +/-5%,100mA max on the 5V rail))
    USB1: spare dashboard-mounted USB port for a USB-key connection (unknown, 5V rail)
    USB2: usb wireless adapter (unknown, 5V rail)

    The GPS will be on pretty much at all times. The keyboard will be connected at all times but its illumination will be turned on only at night, and even then pretty rarely. The LCD touchscreen will, of course, always be connected.

    A problem I see that might occur is that the USB cable will run from the PC in the trunk, up to the inside of the dashboard, where I will split it via an unpowered USB hub. From there it will branch to the 3 USB devices I listed above... Off the top of my head I think the safe distance for USB is something like 15meters, but will running multiple USB devices off the same line cause problems, either that the USB line won't be carrying enough juice, or that the M1-ATX itself won't be able to handle that many USB devices?
    Hang on while I defragment my car...

    the Acura ITX project
    the Acura ITX skin for RoadRunner
    project progress: 99%

  • #2
    USB devices doesn't consumpt more than 500mA each. And USB port normally get its power from 5V STB instead of regular 5V rail. BTW, USB on my ASUS mobo can be power from either 5V STB or 5V rail (selectable by jumper).
    So with all USB devices you have and knowing where the ports get power from, compare it to the PSU spec.
    2004 Matrix XR A7N8X-VM/400 AMD XP-M 2500+, DS-ATX
    89 Supra Turbo P3 [email protected]/Abit BE6 II, Alpine M-BUS Car2PC.
    Y2K Accord Dell GX150
    RoadRunner is the best FE PERIOD
    EmoRebellion is a SCAMMER


    • #3
      After making the original post, I found a new version of the mini-ITX power simulator, which concurs with the 500mA per USB device, outputting 2.5Watts per device.

      The M1-ATX PSU I'm looking at shows this for the specs:

      5V rail: max current = 10Amps
      5VSB: max current = 1.5Amps
      3.3V: max current = 10Amps
      -12V rail: max current = 0.15Amps
      12V rail: 2Amps

      So the 5V rail should be enough to run 4-5 USB devices, plus the 2.5" HDD and the slimline CD-ROM... yes? Especially since the GPS and Keyboard specs I found are rated at 100mA each, not 500. (I just would've figured a GPS unit would require more than 100mA)

      Now I'm wondering if I can safely power the LCD screen (12V) directly off the M1-ATX. If a screen is putting out 10Watts, that's approx .8 (or so) Amps... which doesn't leave me too much to work with on the 12V rail, but then again I won't really need to run anything else on that rail, since the only HDD will be a 2.5"
      Hang on while I defragment my car...

      the Acura ITX project
      the Acura ITX skin for RoadRunner
      project progress: 99%