Battery remaining capacity measuring device

摘要

In a battery remaining capacity measuring device, a current sensor and a voltage sensor detect currents flowing through a load and voltages at both terminals of a battery. A voltage-current changing tendency calculating section collects the detected terminal voltages and the detected currents at every predetermined time, and averages a plurality of terminal voltage values and a plurality of current values at each time when the terminal voltage values and the current values are collected to a predetermined number. A voltage-current approximating line calculating section calculates a voltage-current approximating line using a method of least square having currents as the x-axis and voltages as the y-axis based on the predetermined number of the averaged current values and the averaged voltage values at each time when the averaged voltage values and current values reach the predetermined number. A remaining capacity calculating section estimates a voltage value of the voltage-current approximating line corresponding to a reference current value at each time when the voltage-current approximating line is determined.