A USB device has exceeded the power limits

All of a sudden this error "A USB device has exceeded the power limits of its hub port" appears to your computer screen, and it won't charge your iPhone or iPod to your computer. You turn to the apple community forum or other technology related forums, start asking questions, what happen to your computer USB drive? and people (with good heart) start suggesting you need to check your computer USB ports and the power supplied (500mA) by going to device manager. You don't want to mess with your configuration settings if you don't know anything about it.

Here's a simple trick to check if your USB cable is still working.

1. Your iPhone/iPad normally comes with a wall connector, use it to check if your device battery will charge. If not, proceed to the next test. If you don't have a wall power connector, proceed to the next test. If you can charge the battery, then something wrong with your computer USB ports (very rare scenario).
2. Get another iPhone/iPad USB cable and use it to your computer. I recommend that you reboot your computer, before you use the second USB cable. Because if you don't reset it during the pop-up warning, you computer operating system will automatically disable your USB port. After the computer reboot, connect your Apple device, and see if the battery will charge. If you can charge your apple device with other USB cable, then it is safe to assume that your old USB cable need a replacement.

If you find out that your USB cable is the culprit, normally the Apple USB cable is loose where your iPhone/iPad connected to it. This happen over time, when you connect and disconnect your Apple device to the cable. Try pushing it to the left or right, to check if your Apple device battery will charge. It works for my iPhone, when I pushed the USB cable to right (toward my iPhone), and used a rubber band to hold it to charge my battery. Then I stop by to the nearest Apple store and bought a replacement.

I hope this help you resolve your   "A USB device has exceeded the power limits of its hub port" issue.

Source: Whaddya.com