Can 5v 500mA run a 5v 1.8a device?

No, a 5V 500mA power supply cannot run a 5V 1.8A device. The device requires 1.8A of current to operate properly, while the power supply can only provide 0.5A. Attempting to use the lower-rated power supply could result in insufficient power, causing the device to malfunction or not turn on at all.