05352968 is referenced by 214 patents and cites 13 patents.

Method and apparatus for accurately determining the charge state of a battery is disclosed. The charge state is derived from the battery voltage, which is corrected for errors introduced by temperature and series resistance. Error from series resistance is minimized by either making an open circuit voltage measurement, or by making a plurality of voltage measurements under known load conditions, calculating the series resistance from these measurements, and calculating an equivalent open circuit voltage, compensating for the voltage drop caused by the series resistance of the battery. Errors introduced by temperature induced shifts in battery voltage are corrected by reading the battery temperature and correcting the battery voltage to a reference temperature. The battery voltage corrected for temperature and series resistance effects is used to compute charge state by table look up or algebraically.

Title
Battery charge state determination
Application Number
7/890069
Publication Number
5352968
Application Date
May 28, 1992
Publication Date
October 4, 1994
Inventor
Michael F Culbert
Boulder Creek
CA, US
Daniele Reni
Provo
UT, US
Agent
Robert T Martin
Assignee
Apple Computer
CA, US
IPC
G01N 27/04
G01N 27/27
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