SYSTEMS AND METHODS FOR DETERMINING A REMAINING BATTERY CAPACITY OF A BATTERY DEVICE

A system for determining a remaining battery capacity includes a detection circuitry and a controller. The detection circuitry is coupled to a battery device for detecting an open circuit and a closed circuit voltage of the battery device. The controller is coupled to the detection circuitry, calculates an amount of current drawn out from the battery device based on values of the open circuit voltage and the closed circuit voltage and a resistance of the internal resistor, calculates a present depth of discharge based on the amount of current, and determines the remaining battery capacity of the battery device according to the present depth of discharge.