Patent ID: 8154248

Claim:
A battery charger operable to charge a battery pack having a plurality of battery cells and at least one data terminal providing an under voltage signal indicative of a voltage of the battery cells relative to a low voltage threshold, the charger comprising: a power supply circuit operable to supply a first charge current of a first value and a second charge current of a second value substantially less than the first value; and a charger control module adapted to receive the under voltage signal from the data terminal of the battery pack and operable to direct the power supply circuit to supply the first and second charge currents based on the under voltage signal, wherein the power supply circuit supplies the first charge current when the under voltage signal is indicative of every one of the battery cells being at or above the low voltage threshold, and the power supply circuit supplies the second charge current when the under voltage signal is indicative of any one of the battery cells being below the low voltage threshold.