When building electronics that source power from a USB port, is there anything the device needs to do to get >500mA, or will the port happily supply whatever the device pulls? disambiguation, if needed: I know iPhones, etc check the D- D+ lines to be shorted before they draw >500mA on devices that support supplying that additional current. So on devices that support supplying that additional current, those devices will supply 5V to whatever is connected to +5V and GND (assuming it is kept within its operating range) correct? What's actually going on: I'm planning on using a usb car charger to take 12V from a SLA to 5V for my project. It draws about 1.5A, and the car charger is rated for 2A.