Patent ID: 8649988

Claim:
A service life estimation method for a lead storage battery, the method to be implemented by an estimation unit that estimates an estimated remaining service life of the lead storage battery, comprising: a storage step of storing an integral discharge threshold A that is a reference for determination of a service life of the lead storage battery under a standard condition with predetermined values of a surface temperature, a charge current, and a discharge current of the lead storage battery; a calculation step of calculating an integral discharged capacity B by replacing the accumulated value of discharged capacity when the lead storage battery deteriorates to a level under actual conditions including actually measured values of the surface temperature, the charge current, and the discharge current of the lead storage battery with an accumulated value of discharged capacity when the lead storage battery would deteriorate under said standard condition to substantially the same level as said deterioration level under the actual condition, and a subtraction step of obtaining a differential electric quantity A−B by subtracting the integral discharged capacity B from the integral discharge threshold A; and an estimation step of estimating the estimated remaining service life of the lead storage battery by using the differential electric quantity.