Method and system for charging multi-cell lithium-based battery packs

A method of operating an electrical combination, the electrical combination including a battery charger including a housing, at least one terminal to electrically connect to a battery pack supported by the housing, the battery pack including a plurality of lithium-based battery cells, each battery cell of the plurality of battery cells having an individual state of charge, and a controller, the method comprising:

• controlling, with the controller, the battery charger to supply a charging current to the battery pack through the at least one terminal, the controller being operable to control the charging current being supplied to the battery pack based at least in part on the individual state of charge of at least one battery cell;
• and
• controlling, with the controller, the battery charger to supply the charging current to the battery pack by controlling the battery charger to supply the charging current in a plurality of pulses of charging current, the plurality of pulses each having a first period of time, in which the charging current is being supplied to the battery pack at a predefined amplitude, and a second period of time, in which the supply of charging current is suspended, controlling the battery charger to supply the charging current including modifying, with the controller, the first period of time and controlling, with the controller, the second period of time to be constant.