US Patent 7589491 Temperature compensation in recharging of batteries

Temperature compensation methods and equipment for charging electric storage batteries are described. Control over battery charging includes measurement of battery temperature at the commencement of a charging event, and use of inflection analysis of a charger voltage-time curve to detect the attainment of a distinctive signal point in the event. To compensate for the variations with initial battery temperature on the relation of the signal point to a different battery condition of interest, control of a charging event includes use of the measured battery temperature to obtain from a controller memory information about the applicable values of process parameters pertinent to those temperature-variable process factors. The temperature of a battery charger which includes such controls preferably is used as a workable approximation to battery temperature, so that batteries of conventional construction can benefit from use of the disclosed methods and equipment.