Just about every modern computer peripheral device uses the USB port. Practically all smartphones, tablets, GPS navigation units and portable electronic toys with rechargeable batteries have chargers that use the USB cable to connect the device to a wall charger and to a computer. However, the USB port on a computer was never designed to charge a battery and any of today's portable devices that require charging power above 2.5 watts will not charge rapidly on a computer USB port. Secrets Of USB Battery Charging will explain why your devices will not "Rapid" charge on your computer USB ports...