Abstract

Battery charging apparatus comprising a power source coupled to a battery pack comprising a series connected plurality of batteries, and a charge controller and battery balancer coupled to the battery pack that monitors, controls the charging of, and balances the plurality of batteries of the battery pack. The power source is used to charge all of the batteries under control of a controller. The controller is coupled to an isolated current source in the battery balancer and to a battery voltage sensor. The controller is coupled to a plurality of sensors that monitor predetermined battery conditions. The isolated current source and battery voltage sensor are coupled to each battery of the battery pack by way of a monitoring bus and a plurality of controlled switches. The controller monitors the individual battery voltages using the battery voltage sensor and controls the isolated current source to individually balance low-voltage batteries based upon voltages sensed by the battery voltage sensor.