A method for determining time to completion is provided for a battery charging
system. The system preferably includes a charger having a microprocessor and a
battery with a memory. The memory includes information about the battery, including
battery identifiers, charging states, charging procedures and charging termination
information. The charger reads this battery and then determines the charging states
associated with the battery. The charger then determines the present state of charge,
and calculates a time to completion for that state. The charger then determines
times to completion for the remaining charge states, optionally compensating for
self discharge within the battery. A total time to completion is determined by
summing the times to completion for the respective charging states.
