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Best way to power a Nexus 7 and USB hub?

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  • Best way to power a Nexus 7 and USB hub?

    Hey guys, I'm brand new here but am in need of some assistance, so please bear with me!

    I have a 2000 Toyota Celica GT-S and I'm interested in using a Nexus 7 tablet as the head unit. I've taken a lot of inspiration from here:

    What I want to do is just drop my current head unit back into the dash and then modify my current center console to make the Nexus 7 tablet removable, but also good looking (flush, no gaps between trim and bezel, etc). I also want to wire up a powered USB hub so that I can have the ability to add storage and other USB peripherals later on down the road. What I have noticed is that some people on the NASIOC forum have had trouble with power consumption. That's why I'm coming here!

    I've been researching this for a while now and thought I had most of it down pretty good, but now some new ideas have come from the reading I've done today. Here's what I'm thinking...

    I'd like to use a PSU, like a PicoPSU or something along those lines, to supply the needed power for keeping the tablet charged and running a powered USB hub. Probably a bit overkill, but it will allow for expansion later on as well.

    This is the setup I have in mind, after my research this morning and just some basic searching for parts.

    1. PSU: PicoPSU 120W PSU I don't really know what kind of power I'll need, this could be overkill or not, I don't know.

    2. USB Hub: Anker 4 port USB 3.0 + Charging port 12V powered USB hub, should make things a little less complicated, if I have things straight in my mind... more on this later.

    3. Cables: Micro USB Host OTG Cable

    Those are really the only major things I can think of... I'll need some USB extensions, and I might add a DAC later, but this covers the gist of it I think.

    I plan on mounting the PSU in the center console area, closer to the Nexus 7 so that the cable powering that doesn't need to be so long. Then I want to mount the USB hub in the center console/arm rest that sits between the driver and passenger seat in the front, which would have pretty easy access.

    Now of course I have a few questions...

    1. Is this feasible or am I going way overboard?

    2. Will I be able to get the 12V from the PSU, for the USB hub?

    3. Same goes for the 5V, will I be able to get that from the PSU and have it be able to charge the Nexus 7? The Nexus 7 charger specs are 5V/2A.

    4. I'll use the cable I listed to plug the USB hub into, and then can I add a micro USB male end to the wire I use for power from the PSU, if that works?

    Thanks if read this all, more thanks if you answer!
    Last edited by z3n; 06-04-2013, 02:03 PM.

  • #2
    The USB hub takes 12V power? Are you sure? Most of them are 5V.

    You can likely tear apart 5V cell phone chargers to power the tablet/hub for less money.

    You're going to have to replace the stock kernel on the Nexus 7 to use both USB OTG and charge it. See here.
    "You're just about as useless as JPEGs to Helen Keller" - Wierd Al


    • #3
      I already have Timur's kernel bookmarked, I've seen reference to it before.

      And this particular hub actually does take 12V, which is weird I know. I chose it because I thought it would be easier to not use any step-down converters and this way I wouldn't. Tearing up a cell phone charge probably would be cheaper, I just want to make sure I can easily handle the power needs if I have an external hard drive or other things hooked up to the hub. I know a few people over from NASIOC had some charging problems with the tablet, and I don't really want to have that issue. I figure for $50 or $60 extra, I can do it better the first time.

      Thanks for taking the time to reply! I have quite a while before I set things in motion. I'm currently saving for project #1: All out deadening using Sound Deadener Showdown.