Charging over-discharged batteries with lower current by adjusting duty cycle

摘要

A method for charging a battery in which the duty cycle of the charging current is adjusted to produce a lower charging current. This pre-charging current is provided to the battery whilst the battery voltage is below a threshold voltage indicative of the battery having been over-discharged. Once the battery voltage has reached the threshold voltage pre-charging is stopped and full charging current is applied to the battery. The battery may be Li-ion or NiMH. The duty cycle controller is also provided with a sampled battery current measurement. The frequency of the duty cycle is approximately twice that of the sampling period of the current measurement.