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"USB drawing too much power"

Discussion in 'Gen 3 Prius Technical Discussion' started by ProximalSuns, Mar 24, 2012.

  1. lizardskin

    lizardskin Junior Member

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    Any updates on this? My prius 2012 Three has some issue with my iphone, charging, messages" Too much power..." . And I am not able to charge, access the internet or the music on my iPhone 4 (IOS8).

    If it was just a charging issue, I can use the cigarette lighter to charge.

    But how do I access the internet?
     
  2. ftl

    ftl Explicator

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    Are you using a genuine Apple cable?
     
  3. lizardskin

    lizardskin Junior Member

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    yes genuine apple cable and and i also used an OEM one too. It seems that my car USB is loose? I have to spend more time trying to figure this out before I take it into the dealer for them to figure out.
     
  4. ftl

    ftl Explicator

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    I think if the cable is OK then there must be a problem with the USB in the car. Probably an expensive fix if you take it to the dealer, though.
     
  5. lizardskin

    lizardskin Junior Member

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    I'm under 3y/36K, so should I still be covered under the warranty? I also bought this used 2K ago so I should be covred to 46K/and a 10 months from now.
     
  6. fuzzy1

    fuzzy1 Senior Member

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    How much current does this iPhone draw from USB? If you see no specification, the normal wall charger should list a current figure. If it is more than 500mA (or 0.5 amp), then I can easily believe there is a basic incompatibility between differing USB standards of the car (older) and the device (newer).
     
  7. ftl

    ftl Explicator

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  8. Easy Rider 2

    Easy Rider 2 Senior Member

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    I'm confused.
    NOTHING in the car should be required for Internet access on the phone.
    And if there is a provision for browsing from the console, I would hope it is disabled while the car is moving.
     
  9. GregP507

    GregP507 Senior Member

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    USB power is only 5 volts, therefore line-loss is even worse than 12 volts. In my 2012 PiP, the USB socket is in the center console, therefore the USB line is at least several feet long. It could be part of the reason the USB is underpowered.
     
  10. ftl

    ftl Explicator

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    For the Entune car apps to work with an iPhone, the phone needs to be connected by USB unless the data plan includes wifi tethering. Bluetooth will not work for this.
    Typical use of the Internet while driving is to supply real time traffic info to the navigation system.
     
  11. fuzzy1

    fuzzy1 Senior Member

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    Line loss is built into the USB specs. But the older USB specs were limited to 100 - 500 mA, insufficient for many modern devices,
     
  12. GregP507

    GregP507 Senior Member

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    Line-loss may be built into USB specs, but did anyone tell the Toyota engineers, when they decided that inside the center console was a smart place to put the USB socket?
     
  13. macman408

    macman408 Electron Guidance Counselor

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    It would have to be using some seriously tiny gauge wires to have enough resistance to make a 500 mA current drop the USB voltage below the minimum (4.75V) allowed by the spec.

    At least in the OP's case, my money is on the case maker not meeting the spec. The car needs to implement the whole USB spec to do data transfer to and from the phone, so they probably buy an off-the-shelf USB chip and stick it in the nav system. (Well, Denso or whoever does, anyway.) The case, on the other hand, is just looking for 5V that it can steal, and doesn't really need to be very intelligent about how it does so - at least, in most implementations. To really correctly handle it, they'd have to build a USB hub into the case, and then split the USB into 2 ports; 1 to the phone, 1 to the battery charging mechanism. However, that would drive up the cost of the case; and most of the time, I'm sure their cheap implementation works.

    I'm all for skewering Toyota on its crappy Nav system... but I seriously doubt that it's Toyota that's outside the USB spec here. (That said, their USB port should really support high power. Hopefully soon, other automakers will catch on to Tesla's model of reducing the time-to-market of new features, rather than selling outdated technology for 6+ years.)

    Nobody's asked lizardskin if he's using a powered case or anything else besides just the bare iPhone itself... So consider this me asking?
     
  14. Phil Wheeler

    Phil Wheeler Junior Member

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    Buy your own USB adapter and plug it into the lighter power socket. Mine does 2.1A and provides plenty of oomph.

    Phil
     
  15. GregP507

    GregP507 Senior Member

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    That's exactly what I do. The USB socket is for the flash-drive with my audio files.