Power-saving solar power supply system for automatic vending machine

A power-saving solar power supply system used in an automatic vending machine is disclosed to include a power supply module having a solar cell set and a rechargeable battery set, and a power management unit, which comprises a microprocessor, a voltage detection device that detects the voltage level of the solar cell set and the rechargeable battery set, an idle power supply module and a power switching module controllable by the microprocessor to switch between the solar cell set and the rechargeable battery set so that the idle power supply module provides battery power supply from the solar cell set or the rechargeable battery set to the recognition system of the automatic vending machine when the recognition system is in the idle mode, thereby saving power consumption.