Battery charger with timer-controlled charging, shut-off and reset operations

• US 5,497,067 A
• Filed: 02/18/1994
• Issued: 03/05/1996
• Est. Priority Date: 02/18/1994
• Status: Expired due to Fees

• Current Assignee: Donald E. Shaw
• Original Assignee: Donald E. Shaw
• Inventors: Shaw, Donald E.
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Nappi, Robert E.
• Application Number:
  US08/198,468
• Time in Patent Office: 746 Days
• Field of Search: 320/21, 320/37, 320/38, 320/20
• US Class Current: 320/155
• CPC Class Codes: H02J 7/0071 with a programmable schedule

Abstract

A timer control circuit is coupled with a battery charger to control on a timed basis the charging, shut-off and reset operations of the battery charger. The timer control circuit includes a timer, a d.c. power supply connected to the timer, and an auxiliary relay connected to the timer and connected between a battery and the battery charger. The timer is operable to repetitively and automatically turn on for a first preset timing period, turn off for a second preset timing period, and then turn on again for the first preset timing period. During each second preset timing period, when the timer is turned off, the auxiliary relay is normally deactuated so as to open a feedback path from the battery to the battery charger permitting the battery charger to reset in preparation for initiating a new charging cycle. Then, during each first preset timing period, when the timer is turned on, the auxiliary relay is actuated so as to close the feedback path causing the battery charger to initiate the new charging cycle.

Claims

1. In combination with a battery charger having a charging circuit connect ed to a battery to be charged and adapted to operate to charge the battery, a control circuit having an input connected in a feedback circuit path with the battery and being adapted to sense the charge condition of the battery and to reset in response to sensing opening of said feedback circuit path with the battery, and a main relay connected between said charging circuit and an output of said control circuit and being operable to close a circuit path to said charging circuit to initiate operation of said charging circuit to charge the battery in response to actuation of said main relay by said control circuit as a result of said reset of said control circuit and to open said circuit path to terminate operation of said charging circuit to charge the battery in response to deactuation of said main relay by said control circuit as a result of said control circuit sensing the battery reaching a full charge, a timer control circuit which controls on a timed basis a sequence of charging, shut-off and reset operations of said battery charger, said timer control circuit comprising:

(a) a timer preset to operate to repetitively and automatically turn on for a first preset timing period selected to be of a substantially longer duration than a maximum length of time that said charging circuit of said battery charger would take to fully charge the battery and to allow sufficient time for the battery to partially discharge before another charging of the battery is initiated, turn off for a second preset timing period selected to be of a substantially shorter duration than said maximum length of time that said charging circuit of said battery charger would take to fully charge the battery but of a longer duration than a period of time needed by said control circuit of said battery charger to reset, and then turn on again for said first preset timing period;

(b) an electrical power source connected to said timer; and

(c) an auxiliary relay having an actuator portion and a switch portion, said actuator portion of said auxiliary relay being connected to said timer and actuated by said timer at the start of said first preset timing period and deactuated by said timer at the start of said second preset timing period, said switch portion of said auxiliary relay normally assuming an open condition when said actuator portion of said auxiliary relay is deactuated by said timer and being movable by said actuator portion of said auxiliary relay to a closed condition in response to actuation of said actuator portion of said auxiliary relay by said timer, said switch portion of said auxiliary relay being connected in said feedback circuit path between the battery and said input of said control circuit of said battery charger such that upon initiation of each said second preset timing period, when said timer turns off, said actuator portion of said auxiliary relay is deactuated in response to said timer turning off so as to permit said switch portion of said auxiliary relay to open said feedback circuit path and thereby disconnect the battery from said input of said control circuit of said battery charger permitting said control circuit of said battery charger to reset in preparation for said control circuit of said battery charger to actuate said main relay and thereby initiate another charging of the battery by said charging circuit of said battery charger, whereas upon initiation of each said first preset timing period, when said timer turns on, said actuator portion of said auxiliary relay is actuated in response to said timer turning on so as to cause said switch portion of said auxiliary relay to close said feedback circuit path to said input of said control circuit of said battery charger causing said control circuit of said battery charger to actuate said main relay and thereby initiate another charging of the battery by said charging circuit of said battery charger.

2. The timer control circuit of claim 1 wherein said power source includes a d.c. power supply.

3. The timer control circuit of claim 2 wherein said power source further includes a silicon controlled rectifer connectable to said feedback circuit and connected between said d.c. power supply and said timer for preventing operation of said timer by said d.c. power supply when the battery is disconnected from said feedback circuit.