Patent ID: 11936228
Assignee: BLACK & DECKER, INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G  Y | IPC H

Claim 0:
1. A battery charger, comprising:
an AC impedance circuit to apply a sinusoidal AC excitation signal to a connected battery pack and to measure a battery pack response to the sinusoidal AC excitation signal;
a charger controller including first circuitry to (1) calculate an impedance value of the connected battery pack based on the sinusoidal AC excitation signal and the battery pack response and (2) select a charging scheme based on the impedance value of the connected battery pack;
a power supply including second circuitry to provide the charging scheme selected by the charger controller, wherein:
the sinusoidal AC excitation signal is applied prior to and separate from the charging scheme being provided, and
the charging scheme is provided after the sinusoidal AC excitation signal is applied; and

when the charger controller selects a maximum charging rate charging scheme, the charger controller applies a constant current with a variable termination voltage based on a magnitude of the impedance value of the connected battery pack when the sinusoidal AC excitation signal is set to a value that produces a positive phase shift.