Originally Posted by travellerw
shows that Apple devices going all the way back to gen 3 conform to this standard. You need a certain voltage on the data pins (a resistor divider network).
Unless you have a device that is older then gen 3, you are only getting 500ma charge rate. Even if it seems "crazy fast". UNLESS, you have a 3rd party high speed cable (which has the divider network in the cable).
I have a little device called a USB Charge Doctor that I bought on e-bay for a $5 or so. It goes inline with the USB cable and shows what the device is pulling. I use it all the time to figure out which of my USB adapters are high speed. I keep the high speed ones and toss the low speed ones out...
Ahhhh.... that is why it worked. I have an aftermarket cord. When I put in my iPad
Air it actually charges (about a percentage every minute which is pretty damn fast for that dude)- when I plug
it into 500ma socket it says device not supported. But.... to do this right I need to correct this as who knows what the next gen will be doing or heck.. probably most people just have their OG iPhone cable and will have issues charging
I also found this - more info the better...! Those little step downs produce 5.2 volts so at least in that area we are good.
A general observation with the Apple products is that they will attempt to draw the maximum current
if and only if the voltage level on Pin 1 with respect to the current
draw remains constant between 5 and 5.25 volts. Often, if a charger
is unable to supply the proper amount of current the voltage output will drop. For instance, a 5.25V 1A power supply may only output to 4.5V when under a 2A load. For Apple products, when a device is presented with any one of the voltage configurations (500mA, 1A, or 2A) and then presented with a range of Pin 1 voltage levels from 4.5V to 5.25V, the actual current drawn by the device varies. In our tests, we found that when the voltage sent to the iPad
2 was 4.5V, the iPad 2 drew only about 1A, but steadily scaled up the current to 2A as the voltage was incrementally increased to 5V. Additionally, we noted Apple devices will not accept charge from power supplies with Pin 1 voltages of less than 4.5V or greater than 5.5V.