Abstract: 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.

Abstract: A deep cycle battery is provided that has at least one vent cap. Each vent cap is capable of entry into and exit from a fill opening in a battery cover. The vent cap is attached to the battery cover by a hinge connection which allows for play between the vent cap and the battery cover and which allows for rotation of the vent cap. In one embodiment, a ganged vent assembly is provided in which a flip top cover containing a series of vent caps allows an operator to remove the vent caps from the fill openings all at once, and the insert the vent caps into the fill openings all at once.

Abstract: A method for charging a lead acid storage battery to advantageously extend its life is described. The termination of a charging process is based upon an evaluation of the first derivative (dv/dt) and second derivative (d2v/dt2) of the applied charging voltage. By utilizing the first derivative (dv/dt) and second derivative (d2v/dt2) as charging criteria, an amount of overcharge is applied to the battery that takes into account the precise amount of amp-hours previously removed from the battery. A charger arrangement for performing a charging process of the invention also is described.