BATTERY CHARGE PROGRAMMERS

• US 3,652,916 A
• Filed: 05/28/1970
• Issued: 03/28/1972
• Est. Priority Date: 05/28/1970
• Status: Expired due to Term

• Current Assignee: Gray C. Ballman
• Original Assignee: Gray C. Ballman
• Inventors: Ballman, Gray C.
• Primary Examiner(s): Shoop, Jr., William M.
• Application Number:
  US05/041,423
• Time in Patent Office: 670 Days
• Field of Search: 317/31 320/35,37,39,40,DIG.1,DIG.2 307/252F
• US Class Current: 320/158
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: Y10S 320/32 Voltage divider having diverse elements other than merely plural resistors

Abstract

The disclosure relates to Battery Charge Programmers which permit automatic charging of batteries by regulating the overcharge time of the battery being charged and which contain an overriding charge time limiter, to limit the total amount of time the battery is charged, independently of the state of charge.

Claims

1. A battery charge programming device for use with a battery charger and a battery, said programming device comprising first voltage sensing means for automatically switching on the supply of charging current from the battery charger to the battery at the time a battery is connected to the charging terminals of the charger, cutoff means for automatically switching off the supply of charging current after the charging current has been switched on for a predetermined period of time, and a second voltage sensing means for reducing the amount of elapsed charging time between switching on and switching off if the battery becomes charged prior to the elapse of the predetermined period of time, said first voltage sensing means including a first voltage divider network operatively connected to the charging terminals of the charger, semiconductor means operatively connected to the charging terminals of the charger and to the first voltage divider network in such manner that it will go into conduction when a battery is connected to the charging terminals of the charger, and switching means for supplying charging current from the charger to the battery while the semiconductor means is in conduction, said cutoff means including a first programmable unijunction transistor having a first anode, a first cathode and a first gate operatively connected to the first voltage divider network in such manner that a substantially constant voltage exists between the first gate and the first cathode when the first transistor is not in conduction, and in such further manner that the voltage existing between the first anode and first cathode is determined by the amount of charge developed in a first capacitor, and first resistive means for gradually, over a predetermined period of time, transferring from the first voltage divider network to the first capacitor a voltage charge sufficient to place the first transistor in conduction, and said semiconductor means being operatively cOnnected to the first voltage divider network in such manner that when the first transistor goes into conduction, the voltage supplied to the semiconductor from the first voltage divider network will be substantially reduced and the semiconductor means will go out of conduction, thereby cutting off the supply of charging current from the battery charger to the battery.

2. The device of claim 1 in which the first transistor is connected to the first voltage divider network in such manner that said first transistor utilizes battery power to remain in conduction once conduction has started.

3. The device of claim 1 wherein the second voltage sensing means a second programmable unijunction transistor having a second gate, a second anode and a second cathode, said second gate being connected to a substantially constant voltage source, said second anode being connected to a second voltage divider network which applies a certain percentage of the battery terminal voltage to the second anode, and said second cathode being connected to a third voltage divider network which is also connected, through a blocking diode to the first capacitor for purposes of transferring a voltage from the third voltage divider network to the first capacitor when the second transistor goes into conduction, thereby reducing the time required for the first capacitor to charge.

4. A battery charge programming device comprising:

a pair of sensing terminals;

first voltage responsive switching means for causing charging current to flow to a battery when said battery is connected across the sensing terminals;

Zener means for establishing a point of substantially constant voltage above ground when said battery is connected across the sensing terminals;

a first programmable unijunction transistor including a first gate and also including a first anode and a first cathode;

a first voltage divider network extending between the point of constant voltage and ground and also being connected at an intermediate point to the first gate;

a first capacitor connected at one end to the first anode through a first resistor and connected at the other end to ground;

said first cathode being also connected to ground;

a second resistor of substantial magnitude connected to the ungrounded end of the first capacitor and to the point of constant voltage whereby the first capacitor will slowly develop an increasing charge through the second resistor;

second voltage responsive means for deactivating the switching means thereby causing charging current to stop flowing to the battery when the charge across the first capacitor has attained sufficient magnitude to cause conduction in the first programable unijunction transistor; and

a second programmable unijunction transistor having a second gate and also having a second anode and a second cathode;

the second gate being connected to the point of constant voltage and the second cathode and the second anode being connected to the sensing terminals in such manner that the second programmable unijunction transistor will go into conduction when the terminal voltage of the battery attains a predetermined magnitude; and

means for decreasing the amount of time necessary for the first capacitor to develop a charge sufficient to turn on the first programmable unijunction transistor when the second programmable unijunction transistor is conducting.

5. The device of claim 4 wherein the means for decreasing the amount of time necessary for the first capacitor to develop a charge comprises a cathode resistor in the cathode circuit of the second transistor and coupling means for transfering the potential across said cathode resistor to the first capacitor.

6. The device of claim 5 wherein the cathode resistor is sized to transfer a potential to the first capacitor which is less than the turn on voltage of the first transistor, whereby the first capacitor will continue to charge while the second transistor is condUcting, and the battery will continue to be charged until such time as the first transistor goes into conduction.