The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Sep. 12, 1995

Filed:

Aug. 17, 1993
Applicant:
Inventors:

Toshio Matsumoto, Anjo, JP;

Hideki Watanable, Anjo, JP;

Assignee:

Makita Corporation, Anjo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01M / ;
U.S. Cl.
CPC ...
320 20 ; 320 39 ;
Abstract

A battery charger includes a circuit for monitoring a battery voltage during supply of a charging current to a battery, and a circuit for stopping the supply of the charging current when the battery voltage is decreased by a predetermined value after the battery voltage has reached its maximum value. A first predetermined value is adopted as the predetermined value when an increasing tendency of the battery voltage is detected after a predetermined time has elapsed from starting of the charging operation. A second predetermined value is adopted as the predetermined value until the increase tendency of the battery voltage is monitored after the predetermined time has elapsed from starting of the charging operation. The absolute value of the first predetermined value is determined to be smaller than that of the second predetermined value. The predetermined time is determined to be longer than the period of duration of temporary abrupt variation in the battery voltage which may be produced at the beginning of the charging operation of the over-discharged battery.


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