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Originally Posted by InvisiBill
So does HP, and I'm pretty sure a number of Android devices do as well (though not so proprietary).
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The stock Android kernel follows USB spec, which says that if the data lines are shorted, you can draw up to 1.5A. Any Android device that doesn't do that has a modified kernel, which is unlikely. Try it. Open the battery settings when plugged in, if it says charging USB, then the data lines are not shorted. Short them together and it will say charging AC. It's that simple.
Quote:
Originally Posted by InvisiBill
That seems extremely dangerous. Older chargers used shorted data lines to indicate 1A rather than the standard 500mA. If new devices try pulling 1.5-2A on an older charger because the data lines are shorted, it could burn up the charger. USB's Battery Charging Standard mentions the voltage divider circuits, but I couldn't actually find values that correlated to various current ratings.
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The charger won't deliver more than it can, the voltage will drop instead. The danger is pulling more amps than a cable can safely carry, which could cause dangerously high temperatures in the cable (and excessive voltage drops). The USB Battery Charging Standard is what defines the shorted data lines (at less than 200 ohms). Version 1.2 eliminated allowance for resistive detection of power supply capabilities.
There's a new protocol called USB Power Delivery that dictates negotiation over the data lines to establish power draw, but that is part of USB 3, all these phones are USB 2.
Some devices have additional charging protocols, like Qualcomm Quick Charge, but they still work with standard USB too. Even the Nexus 6 (which I have) supports Quick Charge, if you plug it into a charger that supports Quick Charge then it charges at a higher voltage and amperage, but if you just plug it into a normal charger with shorted data lines it pulls about 1.5 amps.