Automatic nickel cadmium battery cycler

• US 5,280,230 A
• Filed: 06/29/1992
• Issued: 01/18/1994
• Est. Priority Date: 06/29/1992
• Status: Expired due to Fees

• Current Assignee: Michael B. Mahoney
• Original Assignee: Michael B. Mahoney
• Inventors: Mahoney, Michael B.
• Primary Examiner(s): HICKEY, ROBERT
• Application Number:
  US07/907,744
• Time in Patent Office: 568 Days
• Field of Search: 320/14
• US Class Current: 320/132
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: Y10S 320/18 Indicator or display

Abstract

An electronic device for automatically discharging and charging nickel cadmium batteries. When used regularly the device will prevent `memory` from developing in nickel cadmium cells. The prevention of memory development greatly increases the batteries'"'"' useful life and provides for predictable performance. The device is simple to operate, requires no technical knowledge on the part of the user, is completely automatic requiring no monitoring while the device functions, and is relatively inexpensive. The device is intended to replace the standard battery charger while providing a most useful function in addition to charging alone.

The device discharges a battery or multiple configuration of batteries (battery packs) to a very specific level and then automatically charges the batteries at a slow rate. Charge and discharge rates are low to preclude damage to the batteries. The device employes a precision voltage reference which is used to compare against the discharging batteries'"'"' voltage to sense exactly when to exit discharge and enter charge. The precision voltage reference is also utilized to compare against the charging batteries'"'"' voltage so as to indicate when the battery has reached the full charge state. An indicating means is also provided to indicate that discharge is active. The device includes a simple means for disabling the discharge mode so as to function as a charger only and includes a means for restarting the discharge mode at any time.

Claims

1. An electronic, automatic nickel cadmium battery discharging and charging device comprising in combination:

a means for connecting a battery or batteries to be discharged and charged to the device whose terminals are designated (+) Battery Terminal and (-) Battery Terminal and which are referred to collectively as Battery Terminals, the potential of which is referred to as Battery Voltage;

a means for connecting a direct current power supply to the device whose terminals are designated (+) Supply Voltage and (-) Supply Voltage whose potential is referred to as Supply Voltage;

a first section including a first current producing means which connects across said Battery Terminals to perform the discharging function, a first voltage divider connected across said Battery Terminals having an output, and an indicating means to indicate that Battery Voltage is present across said first current producing means;

a second section including a second current producing means which connects across the (+) Supply Voltage and the (+) Battery Terminal to perform the charging function;

a third section including a means for providing a precision reference voltage and a second and third voltage divider, each having an output, each connected across said precision reference voltage and said (-) Supply Voltage;

a fourth section including a first comparing means having at least two inputs and at least one output where the non-inverting input of said first comparing means is the output of said first voltage divider of the first section and the inverting input is the output of said second voltage divider of the third section whereby the output of said first comparing means is sensitive to reduced Battery Voltage providing a signal for the termination of the discharging function;

a fifth section including a current switching means having an input and an output whose input is connected to the output of said first comparing means of the fourth section;

a sixth section including a switching means having a controlling input connected to the output of said current switching means of the fifth section which controls the ON/OFF state of said switching means and having switching terminals whose common terminal is connected to the (+) Battery Terminal, whose normally open (ON) terminal connects said (+) Battery Terminal to said first current producing means of the first section and whose normally closed (OFF) terminal connects said (+) Battery Terminal to said second current producing means of the second section whereby controlling the charge and discharge function of the device;

a seventh section including a second comparing means having at least two inputs and at least one output, a fourth voltage divider having an output, said fourth voltage divider being connected across said (+) Battery Terminal and (-) Supply Voltage whose output is connected to the inverting input of said second comparing means, an indicating means connected to the output of said second comparing means;

the non-inverting input of said second comparing means connected to the output of said third voltage divider of the third section whereby said second comparing means is sensitive to an increased Battery Voltage and giving indication as such;

an eighth section section including a switching means with one end connected to the (+) Supply Voltage and the other end connected to a capacitive means that is in parallel with a momentary closure switching means which in turn is connected to the non-inverting input of said first comparing means of the fourth section providing a means for enabling or disabling the discharge function of the device;

a ninth section including a fusing means connected between the device and either the (+) Supply Voltage or (-) Supply Voltage, an indicating means connected across the Supply Voltage, a capacitive means connected across the Supply Voltage, and a switching means for interrupting the Supply Voltage to the device and for disconnecting said battery from the device.

2. A device as defined in claim 1 where said first and second comparing means and said precision reference voltage may be powered directly from the Supply Voltage or by an additional voltage regulating whose input is the Supply Voltage and whose output is a regulated voltage.

3. A device as defined in claim 1 where the Supply Voltage is direct current voltage and may be supplied by source battery, rectified alternating current, photo-voltaic cells, generator, or other direct current voltage source means.

4. A device as defined in claim 1 where multiple current producing means in the first and second sections may be selected by the addition of a selection means in the first and second sections enabling the device to function properly with a variety of batteries of varying capacities.

5. A device as defined in claim 1 where the momentary closure switching means of the eighth section may be used as a signal to start a timing means and where the change of state of the output of said first comparing means from `high` to `low` may be used as a signal to halt said timing means.