How do I hardwire a 7 port USB hub into my truck for charging USB devices?

Discussion in 'The Coffee Shop ~ Chit Chat' started by PantheraUncia, Sep 1, 2012.

  1. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    nakranij, if you posted the reason for needing/wanting 7 ports, sorry, I missed it. Could you advise please.

    In your 1st post, you suggested the main problem with the USB chargers was the fact that they were automobile USB charges; but, I think you are now planing to use 7 auto USB chargers, how can this cure your problem?

    I'm sorry, I did not see this thread when you 1st posted; I have many years of electronics experience (including soldering, hehe), if you need any help, let me know.
  2. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    I get the sense that he wants all ports to be 2amp connections so that each can power an iPad or other tablet that needs 2amps.

    Most USB hubs power as if it were a data connection ... i.e. 1/2 amp. I've never seen a hub with the data pairs of the USB ports all shorted to allow 1amp draw ... but there are USB adapters that short the data pair of a single port for this express purpose, making devices think it's a wall socket and not a hub or data device that's in use. Regardless, neither approach spits out 2amp at the terminals. Hence the approach Nak is taking?

    That's my best guess...
  3. PantheraUncia

    PantheraUncia Epic Member 5+ Years 1000 Posts

    Right now, the most power hungry USB devices need 2.1amps to charge (Ipad, newer Iphones, newer Android phones, Android Tablets).

    As it stands, I have:

    • Samsung Galaxy S3 (personal phone)
    • Iphone 4s (Work phone)
    • Ipad 3
    • 3 Nexus 7 tablets (This is a project in progress/ more to come later)

    I also take allot of small day trips with friends and they have 1 phone and 1 tablet also.

    So I typically need 6 USB ports to charge those devices at 1 time.

    Unfortunately there are no USB hubs that can pull that many amps (2.1amps per port). Even the ones that you plug into a wall at home only pull 3.1amps between 7 ports.

    I am building a (Hate to use the term "HUB"); but a 7 USB port charging station that pushes 2.1amps to each of the 7 ports that will work in my truck on 12v DC.

    I am not going to say I am doing it the best way, but the way I am doing it, each port has its own DC regulator and electronics so if one port fails, they all do not fail. :) so I am not pushing too many amps to each port and fry the devices that are plugged in.

    If this goes well, I might make another identical charging station that I can put in the rear of the truck somewere for the back seat drivers......
  4. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Hmmm, big load; of course, your operating on the assumption that all will need to be charged at the same time.

    Be mind full, the 12v port (cig lighter) can be overloaded. Good luck
  5. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    Putthe back seat drivers in the truck bed!
  6. PantheraUncia

    PantheraUncia Epic Member 5+ Years 1000 Posts

    I am watching that, it should be about 15 amps when finished, so I am thinking as I get them done, I will think about running a separate line with its own fuse from the battery and maybe add a relay so it is only on when I turn it on.

    - - - Updated - - -

    haha, might have to.
  7. PantheraUncia

    PantheraUncia Epic Member 5+ Years 1000 Posts

    Ok, so an update to this project:

    Keep in mind this is a work in progress and I am no were near finished :)

    This is 14ga + & - wires for my main power feed and ground for the USB Charger for my mobile devices. These wires are rated up to 20 amps of draw. I fed them through the firewall into the dash and brought them out at the most convenient place for the moment (that space was a blank in my truck).

    This is a temporary crimp connection between the 14ga and the 18ga wires (leads) I soldered to the USB charger. (I did a crimp so I can undo the wiring in the future to maintain the 14ga main feed and ground wire until I am done designing the final USB Charging station for my dash.

    This is the Cigarette lighter USB Charger on the other end of the 18ga wires showing dual 1am (2amp/ 2000mah) USB Ports. ( I am using electrical tape as a temporary solution until I design my permanent plate for the dash so none of the electronics touch other stuff and short things out).

    This is a 28AWG/1P+24AWG/2C USB cable with a Ferrite Core around the end that goes into the USB device (Phone, tablet, etc)

    This is a picture zoomed out a little bit.

    I checked with a volt/amp meter and all my voltages/amps check out and I tried charging a HTC EVO 4G and a Samsung Galaxy SIII on this setup and both were charging and showing progress without the battery getting hot or exploding, etc.

    The beauty of this setup is all the electronics to regulate the voltage and amps pulled through the USB ports are already built in the the cigarette lighter USB charger I gutted out. I just had to verify that once all the connections were made I double checked them before plugging in the phones to charge them.

    I am going to purchase 3 more of these dual port chargers, gut them out, wire leads to them which would put me at 8000mah draw or about 8 amps @ 5volts. In the end I will have 8 USB ports pulling 5 volts each @ 1amp per port or 2 amps per pair of ports. Then I get to clean up the wires, and build out my new face plate to do the clean install and make it look "factory".

    Ah one key thing I did forget to mention, the positive (hot wire) is fused under the hood near the battery with a 3amp fuse right now. As I add the additional USB ports (ending with 8 total), I will upgrade this to an 8 or 10amp fuse.
  8. PantheraUncia

    PantheraUncia Epic Member 5+ Years 1000 Posts

    Hi RayVoy,

    I am no electronics expert so any help I can get would be great. I just updated this thread with new updated pictures and notes.

    My first set of 2 USB ports are working fine. I am going to buy 3 more of these "USB Car Chargers" that plug into the cigarette lighter, gut them out, solder wire leads on to them, which will actually end up giving me 8 ports instead of 7 (4 sets of 2 ports each).

    My issue now is designing a face plate for the dash that looks factory to place them in the dash :).

    I am also struggling with the "right way" vs the "easy way" to take 4 positive leads and 4 negative leads (From the USB Ports) and wire them into the higher gauge wire coming in from the battery and the ground back to the frame).

    I have heard about a "block" where my hot and ground power the block(from the battery) and then I have a hot and ground for each of the leads (from the devices) with screws so I can add and remove (plug and un plug) things from the block but the block maintains power.

    Something like this: this one is rated up to 65amps (I would never need that much for USB ports unless I had like 60 of them.

  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Hey @nakraniji nice looking work.

    The correct way, is to do it in a way that provides the longest reliability. My suggestion, is to splice them together in what was once known as a telegraph splice.


    Keep the #14 wire on one side, and all of the USB power leads on the other side (for each polarity), solder the joint and protect it with a piece of heat shrink tubing (be sure to pick a piece that will slide over the joint, and slide it over the 14 ga before you solder. Small pieces of heat shrink will shrink with a hair dryer, but for something like your doing, a heat gun may be required. If you don't have a heat gun, an open flame (stove, or torch) can be used, just watch it closely.

    These blocks are great if a lot of splicing is going to be done and you have the room and the wire to mount it. Personally, I only use them when the project is inside and in a metal/plastic "can"; for automobile use, I only use them for prototyping.
  10. Joseph Bennett

    Joseph Bennett New Member

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