Using a USB Hub for Data and Charging

Discussion in 'Customizing & Modifications' started by Unplugged, Sep 14, 2018 at 6:00 PM.

  1. Unplugged

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    I was in a quandary over how to charge two phones from the front charging pads AND use my USB flash drive for music. As most know, the wired charging pad in the console is the only place where data is transferred to the Model 3.

    Also, I have ordered a Nomad wireless charging pad, and it is suggested that both USB ports be used in order to obtain full charging. I ordered a compact USB hub from Amazon, and used my USB tester to determine if there was any loss in amperage due to the hub.

    I am attaching photos of my tests. My cheap little tester shows 1.14 amps from the hub at 4.96 volts. (The little white thing on top of the hub is my USB flash drive.) For comparison, I also photographed the right side without the hub, showing also 1.14 amps at 5 volts.

    I moved to the house and took a photo with a standard USB and also got 1.14 amps at 5.24 volts. I was starting to get worried that my USB meter was stuck at 1.14 amps. So I tried a known slow charge USB port on my computer. This showed 0.38 amps at 4.97 volts.

    So it looks like I will be using the USB hub to use my data off the flash drive, while also charging my phone. FYI, the music does play just as exceptional with or without the hub.

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  2. batzman

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    Can you post the links to the hub you purchased for your project and also the meter? I’d like to look into both of them myself.
     
  3. Unplugged

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    An update. I realized that I may not have been using enough power to get an accurate reading. I placed two cell phones on the tester outputs for more amp draw. I did get a change.

    With two cell phones drawing amperage, I show 4.96 volts and 2.30 amps without a hub. With a hub, I show 4.92 volts and 1.51 amps. So with a hub, there is a loss of 0.8 amps. Whether this will make much of a difference is up to you.

    Interestingly, I compared that to the draw from a 2.5 amp rated power port (cigarette lighter) adapter and got 5 volts at 1.62 amps. Weird that the power port on the Model 3 isn't producing more amps, but maybe that's my adapter?

    I have photos of all tests, if someone would like to see them all.

    I have ordered a new aluminum hub which I should get tomorrow. (The plastic one just seems too fragile and un-Model 3-like.) But here are the links to all:
    Plastic hub:
    Aluminum hub:

    Tester:
     
  4. Unplugged

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    I didn't realize amps volts and wattage was such an easy calculation.

    Here's an explanation of all three, from https://www.howtogeek.com/175734/htg-explains-can-you-use-any-charger-with-any-device/

    • Voltage (V) is the water pressure.
    • Amperage (A) is the volume of water flowing through the pipe.
    • Wattage (W) is the rate of water output, which is found by multiplying the voltage by the amperage.

    I guess the easiest method is to just provide wattage numbers. Here are my findings in watts:

    All of these watt numbers are based on using two Samsung Galaxy S8+ cell phones as current draw. I assume that the Nomad and other wireless charging pads can draw more power, so your experience will vary.

    At the front USB port: 11.4 watts
    Front USB port with hub: 7.4 watts
    Power port (cigarette lighter): 8.1 watts –
    This is using one port of a dual port car charger rated at 2.4 amps at each port. (Which means it should be capable of 12 watts.)
     
  5. Unplugged

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    Here is a final update photos using two Samsung Galaxy S8+ phones for the current draw and the new aluminum USB hub. The hub allows 7.4 watts on these two phones.

    Once I (eventually) receive the Nomad wireless charging system, I will provide actual watts from the device from the left port and the right side hub.[​IMG]
     
  6. mishakim

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    Have you actually used this hub to charge more than one phone at a time, and also used it for music simultaneously? The product listing specifically says the max combined current draw is 900 mA (which is the USB 3.0 spec limit for a data port), and that it's not meant for charging, only data. A frequent problem with trying to use a bus-powered hub for charging is that pulling too much current can destabilize the data connection, so even if you can charge, you can't use it for data at the same time. The better approach would be to get a hub with an external power supply that can be connected to the 12V power port - that would be able to provide multiple amps per port for charging, and still allow data on at least one port.

    BTW, what you said about amps vs watts is true, but since normal USB is always 5V, most discussion of USB charging limits and capacity refers to the current draw. Watts come in to play when looking at non-USB charging, like inductive, or when dealing with USB-C which can deliver more than 5 volts.
     
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  7. Unplugged

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    #7 Unplugged, Sep 17, 2018 at 2:48 PM
    Last edited: Sep 17, 2018 at 8:21 PM
    Thanks for your comment. I have no experience with low voltage items, so any suggestions are appreciated.

    I used both S8+ phones off the tester and both were charging the phone battery, and I played the USB music as well. I'm not sure how much one-half of the 6,000mAh battery inside the Nomad wireless charging pad will draw. The USB music playing was stable, but that was with a draw of around 2 amps.
    I can't find any such info on the Nomad specs.

    If I went to the trouble to power a hub, I would probably just use the power tap to run the phone or wireless cords instead, and a hub would be unnecessary. I guess I will have to wait and see how much power the wireless Nomad draws and how the hub reacts to that. This is all the fault of Tesla, who made data ports only on the two available power ports in the console.

    I agree that the aluminum hub info states that it is not for charging devices, but I got nearly the same voltage and amp specs from that hub as I did with the black plastic hub that says it can charge only one device. Perhaps it will make a difference with more current draw. I will have to compare the two hubs once the Nomad wireless charger comes in. In the meantime, it is working with charging one device on the Tesla pad.

    EDIT - Just to be clear, I don't intend to power more than one device off of any hub. (It's just that there are no two port hubs out there.)
     
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