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  • Power USB devices

    I need extra power for my USB harddrive and USB DVD player. I've read up on the topic and even made various posts. But, I just stumbled arcross the "CNX-P5V 15 Watt +5V Regulator". Not a bad price. I know I could make it myself, but this seems easier. 15watts is way more than enough. 3 watts would probably be sufficient. Is there a similar option that would be easier / cheaper? Any ideas? Am I being silly? Maybe I should build it?

    Scott

  • #2
    Originally posted by spdyscotty
    I need extra power for my USB harddrive and USB DVD player. I've read up on the topic and even made various posts. But, I just stumbled arcross the "CNX-P5V 15 Watt +5V Regulator". Not a bad price. I know I could make it myself, but this seems easier. 15watts is way more than enough. 3 watts would probably be sufficient. Is there a similar option that would be easier / cheaper? Any ideas? Am I being silly? Maybe I should build it?

    Scott
    How do you figure that 15 watts is WAY MORE THEN ENOUGH. That is just 3 amps. And, 3 watts is about .6 of an amp. Are you only powering a single device?

    According to some powe supply calculators, each USB device is an amp (5 watts), that means the most you can connect to that PS is 3 USB devices. Perhaps you only have 3 or less, and then you are golden. But, if you have more (My 4 port hub I think is full) that might not be enough.

    Now, the last time I responded to a post of yours, some of us discussed a 5 amp 5volt PS, that is 25 watts. That should be enough for 5 USB devices.

    Also, Optical drives and Hard drives draw about an amp each, if not more. That is at least 10 watts. You are seriously gonna be getting close to that max. Add a Mouse, or GPS receiver, and your probably done for.

    Look here
    http://www.jscustompcs.com/power_sup...or.php?cmd=AMD

    Michael
    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

    Comment


    • #3
      My bad. I confused watts for amps. Not knowing 5 watts = 1 amp, I guess 3 amps is just perfect. I need to power a DVD drive (1.3 amps) and a HD (maybe 1 to 1.5 amps). My other USB devices will be powered directly from the ports. So is the "CNX-P5V 15 Watt +5V Regulator" a good way to go?

      Comment


      • #4
        I'm also a little confused about the "hub". I have a 4-port hub in my PCMCIA slot of my laptop. There is a small DC power port on it. Am I supposed to connect that to a 5V power source? I was under the assumption that that port was an output? Anybody know what I'm talking about?

        Comment


        • #5
          Originally posted by Wiredwrx
          According to some powe supply calculators, each USB device is an amp (5 watts),
          I could be wrong, but USB Powered Devices can only pull a max of 500 mA (or 1/2 amp).

          Personally, I'd run a 5v regulator with a relay (turn the relay on and off with the 12v power of the computer, so it turns the hubs on and off when you turn the computer on an off.)

          I have a second power supply to supply my USB devices. I hooked up the ACC line for that power supply to the 12v output of my OPUS 150 that powers my computer, that way it turns on when my computer is on.

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          • #6
            spdyscotty,

            Here are some actual measurements of USB devices in my system. One device not listed is the Audigy 2NX which draws about .8 amps. Hopefully this info will help.
            Attached Files
            MikeH

            Comment


            • #7
              Originally posted by spdyscotty
              My bad. I confused watts for amps. Not knowing 5 watts = 1 amp, I guess 3 amps is just perfect. I need to power a DVD drive (1.3 amps) and a HD (maybe 1 to 1.5 amps). My other USB devices will be powered directly from the ports. So is the "CNX-P5V 15 Watt +5V Regulator" a good way to go?
              Ya, that will probably work. Watts=Amps*Volts. So, 2 amps at 5 volts is 10 watts, 2 amps at 12 volts is 24 watts.

              Michael
              ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

              Comment


              • #8
                Originally posted by MikeH
                spdyscotty,

                Here are some actual measurements of USB devices in my system. One device not listed is the Audigy 2NX which draws about .8 amps. Hopefully this info will help.

                That's cool.

                Can you measure some USB HDs or Optical drives.

                The other things seem quite "obvious" as they do not include any spining motors. I guess I would figure that Mice (Or is it mouses, I forget) and the GPS receiver were not that heavy on the amperage load, but if you look above, the DVD and the CD use more then 500ma, and in fact, over an amp during spin up. I wonder if thoe numbers change for a 5 volts device (assuming of course that the DVD and CD ROM you were testing were 12 volt devices)

                EDIT: Oh ya, I am wondering how you measured those current draws.

                Michael
                ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

                Comment


                • #9
                  Oh ya, I am wondering how you measured those current draws
                  Looking back on this chart, there is an error in the calculation of total power. All of the USB devices were measured by inserting a current meter in the USB +5V supply line. So the power associated with these devices should be calculated at +5V, not +12V (the summary at the bottom of the table is wrong). However, the currents shown for the USB devices is correct and directly measured on the USB cable.

                  Also, the CD/DVD drive was USB attached. So its currents are for a +5V supply. I don't have a USB HDD to measure. Sorry.
                  MikeH

                  Comment


                  • #10
                    Originally posted by MikeH
                    Looking back on this chart, there is an error in the calculation of total power. All of the USB devices were measured by inserting a current meter in the USB +5V supply line. So the power associated with these devices should be calculated at +5V, not +12V (the summary at the bottom of the table is wrong). However, the currents shown for the USB devices is correct and directly measured on the USB cable.

                    Also, the CD/DVD drive was USB attached. So its currents are for a +5V supply. I don't have a USB HDD to measure. Sorry.

                    No problem. Thanx for the information.

                    Michael
                    ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

                    Comment


                    • #11
                      Okay, so what exactly is the need to power the hub??? Mine plugs right into my laptop and I thought it got power from the laptop it's self.

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                      • #12
                        Many USB hubs allow "non-bus power" which is essentially a barrel plug on the side of the hub that accepts an external +5V supply. There's a picture of a powered hub HERE (bottom of page). If you have power hungry USB devices (ie Audigy USB sound card) you can provide external power to the hub instead of loading down your PC's PSU.
                        MikeH

                        Comment


                        • #13
                          I see. Mine does have a DC jack. It came with a DC jack -> USB connector. I thought that cable was to provide power to USB devices without wasting a USB port. How am I supposed to use that cable. You think that jack is to help power the devices I plug into the ports? I should connect 5V to that jack?

                          Comment


                          • #14
                            Originally posted by spdyscotty
                            I see. Mine does have a DC jack. It came with a DC jack -> USB connector. I thought that cable was to provide power to USB devices without wasting a USB port. How am I supposed to use that cable. You think that jack is to help power the devices I plug into the ports? I should connect 5V to that jack?

                            Well, it would depend if that DC Jack--> USB connectorhas a "USB Port", or a "USB plug." If it is a plug, it is used to power the USB Hub with a second source of power. However, it still is limited by the total power available on the USB bus, it will double the availabel power to the hub though. This is most likely what it is.

                            If it is a USB Port, then I have no idea what it could be used for. However, how could it be used to "Usb devices without wasting a USB port". Where would the power be coming from if not from the USB ports on the computer?

                            I know I am a stickler for this, but you really should be as specific and detailed as possible when posting. The HUB probably has a "DC Jack" while the cable has a "DC Plug". Plugs, Jacks, Ports all mean different things.

                            I won't even get into Female and Male connectors, that is a different conversation.

                            Michael
                            ...I love the French language...especially to curse with...Nom de Dieu de putain de bordel de merde de saloperies de connards d'enculés de ta mère. You see, it's like wiping your *** with silk, I love it.

                            Comment


                            • #15
                              I couldn't be more specific as that is my question. I don not know if it is intended to supply 5V or inteded to accept 5V. Also this device slides into my PCMCIA slot and perhpase it is technically a USB Bus (not a hub). I had to use it b/c my laptop did not have a USB 2.0 port on it.

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