How-to Charge iPad with Computer
Many Apple users have complained that their iPad shows “Not Charging” while plugged into their computer. The explanation for this is that the iPad requires more amp than the USB port can supply.
Apple’s support states, “iPad will charge with any Apple USB Power Adapter and will also charge, although more slowly, when attached to a computer with a high-power USB port.” Most computers have standard USB ports that do not provide enough amp to to charge the iPad with the screen on. The power required to keep the screen on exceeds the charging rate of a standard USB port. Therefore, by keeping the screen off, the iPad will charge slowly.
How-to Charge iPad Faster with Computer
ASUS has provided a free simple program called ASUS AI Charger that boosts the charging rate of the USB ports. It works by boosting the port to a higher output. Many report success after installing this utility.