Abstract: A system for charging a storage battery initially charges the battery at a maximum rate of current which tapers in magnitude until the battery attains a selected voltage, and thereafter charges the battery with a continuing reduction of current until termination. Termination is accomplished by sensing current delivered to the battery over time, monitoring a curve representative of such data, and discontinuing charger operation when the slope of the curve attains a selected value.

Abstract: A method for charging a lead-acid storage battery, the method comprising the steps of charging the battery at an initially high rate during an initial stage of the charging cycle, monitoring the internal battery voltage, charging the battery at a lower, finishing rate after a preselected battery voltage has been monitored, and periodically interrupting the finishing charge until the battery is recharged.

Abstract: In a battery charging circuit for charging a battery load characterized by having a substantial effective capacitance, a transformer is connected in a Scott T configuration, the transformer input being adapted for connection to a three phase power line, and the transformer output circuit being in a four phase star configuration for providing a four phase charging circuit. The transformer additionally contains a pair of ferroresonant circuits, each such circuit containing a capacitance selected to cooperate with the capacitance of the battery so as to provide the desired charging characteristic.