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Powering a USB hub? 5v options?

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  • Powering a USB hub? 5v options?

    Okay let's see here. I guess I'm trying to clean up my USB cables. If I get a 4-port hub for my center console I can run 1 cable to it and have my Lilliput and Powermate on it with no problems and still have extra ports for a card reader, OBD-II reader, whatever. Sounds good to me.

    This is the one I like. Now, how do I power it?

    I suppose I could run a 12awg wire off the 5v line of the Opus, but that would draw even more of it's very limited power. I'm pushing it's limits as it is. And it would also be annoying to run another wire (isn't this what I'm trying to avoid?).

    I could tap into the cigarette adapter's 12v line with a 12v->5v adapter. Think it could handle 2 amps for the hub (500mA x4) ? I could also use the 12v from my headunit's wiring harness. Where do I get one of those adapters anyway? I couldn't find it at radioshack. It has to be a regulated 5v right?

  • #2


    • #3
      You wont need a powered usb hub for those items mentioned. But if you still want to, you can just take a lead from the molex connector on your psu and run it to the hub.
      2.4 celeron
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      dual optimas
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      My Truck


      • #4
        I don't want to use the lead from the psu because my psu is being stressed out as it is, plus that means I have to run another cable.

        The Powermate requires it's own USB port. It wouldn't play nice with the Lilliput and whatever else I wanted to put on a self-powered hub.


        • #5
          get one of these for every amp, and a nice little heatsink

          I think radioshack or someone makes 5V car adapters for charging your palm or other USB powered could get one of those and do surgery....
          Cheap Laptop, great for Carputer!


          • #6
            I've been thinking about this as well.

            I think the right way to do this is have a 12v-5v converter connected to a relay. The relay is turned on by the 12v line on the PSU.

            I have a couple of other items that need power besides a USB hub. I think this is the way I am going to do it. A relay puts only a tiny load on the PSU.


            • #7
              I can tell this is gonna be one of those threads thats over my head I don't know what regulator does, I don't know what a relay does... I think I'll just run 2 usb cables up front and hope that nothing needs too much juice.


              • #8
                That iogear is little bit bigger than some of the other harmonica type hubs so that it can store the cable inside, and the cable is only about 6 inches long. It's not something you really need for permanent placement. Also, if you get one with a USB mini jack it usually comes with a 3ft cable, or you can get a longer USB A to mni cable. Just one less connection.


                • #9
                  fyi.. a regulator pretty much regulates the voltage... it takes that 12V-14V coming from your alternator and regulates it to 5V +/- X (where "X" is a small voltage, ideally 0).

                  Relay kinda acts like a electrically controlled switch. If you connect the 12V from the power supply to the switch input of the relay, it'll suck up almost no juice. For all practical purposes, you can say it doesn't suck up any juice.

                  But since that 12V from the power supply is set high only when the power supply is on, it'll turn on the relay, so the relay will pass the 12V-14V from the alternator to the regulator, which will then convert down to a clean 5V.

                  WIthout the relay, you'd always get 12V to the regulator, wasting electricity when the power supply is off.


                  • #10
                    Thanks for the info


                    • #11
                      So, two 5v regulators on a wire led from the cigarette adapter will produce enough power for the USB hub. 2 amps at 5v. It's gonna need a heatsink. 2 regulators, 1 heatsink, less than $5.00 at radioshack.

                      I have never done anything like this before. Can anyone post a pic of how it should be wired up? I see 3 prongs on the regulators. And the heatsink.. how am I gonna keep it attached ?


                      • #12
                        The radioshack linear regulator has a schematic on the back of the package. If you get tired of trying to keep it cool, do a search for switching regulators. They've been mentioned quite a few times here.