Battery remaining capacity measuring device

Abstract

A current/voltage detecting section detects current flowing through a load and terminals voltage of a battery. A correlation determining section obtains the correlation coefficient between a plurality of current values and a plurality of voltage values detected by the current/voltage detecting section to determine whether or not the correlation coefficient is equal to or less than the predetermined value. A data acquisition range determining section determines a data acquisition range adjacent to the previous approximating line stored in a memory when the predetermined values is determined as equal to or less than the predetermined value, and deletes data which are not included in the data acquisition range from the plurality of the current values and the plurality of the voltage values detected by the current/voltage detecting section. An approximating line calculating section calculates the approximating line to be stored in the memory based on a plurality of current values and a plurality of voltage values determined by the data acquisition range determining section. A remaining capacity calculating section calculates the remaining capacity of battery based on the plurality of the current values and the plurality of the voltage values determined by the data acquisition range determining section.