Abstract: An apparatus and method for charging a battery are described in a technique wherein charge pulses are followed by discharge pulses and then first rest periods and other discharge pulses followed by second rest periods. Selected ones of the second rest periods are extended in time to enable a battery equilibrium to be established and the open circuit voltage of the battery to settle down and reflect an overcharging condition of the battery. By comparing the open circuit voltages measured during different extended second rest periods small voltage decreases can be reliably detected and used to determine an overcharging condition such as when gases are generated and affect the open circuit voltage. Once overcharging is detected the battery charging is stopped.

Abstract: A charge pulse (200A) is applied to the battery (B). The open circuit voltage of each cell (C1-CN) is then measured during a first rest period (210A). A depolarization pulse (220A) is then applied to the battery. The open circuit voltage of each cell is then measured during a second rest period (210B). The open circuit voltages for the first and second rest periods for each cell are compared to yield a voltage difference (DELTA Y). This voltage difference is then compared with a threshold voltage (V THRESHOLD). If the voltage difference is greater than the threshold voltage then the cell is being charged too rapidly, or is being overcharged, so one or more of the charge cycle parameters are adjusted.

Abstract: A method and an apparatus for adjusting the process of charging a battery so as to charge the battery as rapidly as possible while avoiding overheating of or damage to the battery. The method provides for applying a charging pulse (C1) which provides an average charging current, applying a first depolarizing pulse (D1), waiting for a first rest period (DW1), measuring the voltage (V1) at a predetermined point within the first rest period, applying a second depolarizing pulse (D2), waiting for a second rest period (DW2), measuring the voltage (V2) at the predetermined point within the second rest period, determining a difference between the voltage (V1) and the voltage (V2), and decreasing the average charging current if the difference is greater than a predetermined amount. The present invention also provides for determining whether the battery is low on water.