When you’re always on the go and usually charge your phone or tablet with a laptop or PC in the office or an USB port in the car, have you noticed that charging this way takes a really long time? And it’s almost impossible to actually increase your phone’s battery power if you’re using it as a GPS even while your phone is plugged in into your car's USB port; that's because your phone is using more power than the power your USB port can supply to your phone.