| Abstract |
A novel pulse charging system is described for the rapid charging of lead acid batteries, based on a series resonant converter, designed to charge a lead acid battery as rapidly as it is practicable without shortening its operational life. This system charges the battery using a train of high current pulses, the duty cycle of which varies according to the state of charge of the battery. As the state of charge of the battery increases, the average current supplied to the battery is reduced in order to minimise gassing. This is achieved by reducing the duty cycle of the pulse train, i.e. by increasing the time interval between the pulses of charge. For a typical 12V, 100Ah battery, the current pulses can reach a maximum amplitude of 600A, and of 50s duration. The converter incorporates discharge pulses between the charge pulses as this has been shown to improve charge acceptance. The discharge converter returns a fixed percentage of the charge supplied to the battery during the previous charge pulse back to the power supply, as this reduces the potential of the positive plate (relative to the potential of the electrolyte) and therefore reduces oxygen production. |
