BATTERY CHARGER CONTROL

• US 3,794,905 A
• Filed: 10/17/1972
• Issued: 02/26/1974
• Est. Priority Date: 10/17/1972
• Status: Expired due to Term

• Current Assignee: Ronald E. Long
• Original Assignee: Ronald E. Long
• Inventors: Long, Ronald E.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/298,344
• Time in Patent Office: 497 Days
• Field of Search: 320/20,21,37,39,40,DIG.1,22
• US Class Current: 320/161
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient

Abstract

To control a regulated battery charger that is providing a regular charge to a battery, a comparator compares the potential of the battery with the potential from a digital-to-analog converter, and in response to this comparison: (1) activates a multivibrator when the potential of the battery is greater than the potential of the digital-to-analog converter, with the multivibrator pulsing a first counter that is connected to the digital-to-analog converter so that the count of the first counter and the potential of the digital-to-analog converter follow in discrete increments the increase in the potential of the battery as the battery is charged by the battery charger; and (2) provides reset pulses to the reset terminal of a second counter each time that the potential of the battery increases above the potential of the digital-to-analog converter, with the second counter causing the battery charger to be de-energized when it reaches a predetermined count between reset pulses.

Claims

1. A method of controlling the charging of a battery comprising the steps of:

charging the battery at a rate above a certain rate;

sensing the energy level of the battery;

generating a plurality of energy-level digital signals, each corresponding to a different energy level of the battery;

determining when the time elapsed between at least certain of said energy-level digital signal exceeds a predetermined maximum time; and

reducing the rate of charging the battery below said certain rate when said elapsed time between said certain energy-level digital signals increases above said predetermined maximum time.

2. A method according to claim 1 in which the step of reducing the rate of charging of the battery when said elapsed time increases above a predetermined maximum includes the step of reducing the rate of charging of the battery when the time after a first of two successive energy levels exceeds said predetermined maximum time before the second of two successive energy levels is reached.

3. A method according to claim 1 in which:

the step of sensing the energy level of the battery includes the step of classifying the energy level of the battery at the start of a charging run into different classes each corresponding to a different one of a plurality of ranges of energy levels of the battery; and

the step of reducing the rate of charging of the battery when said time increases above a predetermined maximum time includes the step of selectively reducing the rate of charging of the battery when said predetermined maximum time is a first maximum time for an energy level at the start of a charging run in a first class and reducing the rate of charging of the battery when said predetermined maximum time is a second maximum time for an energy level at the start of the charging run in another class.

4. A method according to claim 3 in which the step of classifying includes the steps of:

determining the length of time required for the battery potential to reach a predetermined amplitude from the time the charging run starts;

generating a first classification signal when the amplitude reaches said predetermined amplitude prior to said predetermined time; and

generating a second classification signal when the amplitude fails to reach said predetermined amplitude in said predetermined time.

5. A method according to claim 4 in which the step of determining when the time elapsed between at least certain of said energy-level digital signals includes the steps of:

generating a series of periodic timing digital signals representing successively longer time periods starting with the time of occurrence of one of said energy-level digital signals; and

applying said series of timing digital signals to a timing counter, whereby successive output terminals of said counter represent successively longer Periods of time from the occurrence of said one of said energy levels.

6. A method according to claim 1 in which the step of generating energy-level digital signals includes the steps of:

generating a series of digital signals representing successively higher values;

converting at least certain of the digital signals to analog signals having corresponding values;

comparing the analog signals with the energy level of the battery; and

terminating the generation of signals while the analog value and the energy of the battery are in a predetermined relationship with each other, whereby the energy-level digital signal are proportional to the energy level of the battery.

7. A method according to claim 1 in which the step of charging the battery includes the step of applying a regular charge to the battery.

8. A method according to claim 7 in which the step of reducing the rate of charging includes the step of reducing the rate of charging to zero.

9. Apparatus for controllung the charging of a battery comprising:

input means for carrying a signal representing the potential of a battery;

measuring means for generating a plurality of energy-level digital signals indicating energy levels of the battery;

timer means for determining when an elapsed time between at least certain of said energy-level digital signals exceeds a predetermined maximum time; and

switch means for reducing the rate of charging of the battery when said elapsed time between said energy-level digital signals exceeds said predetermined maximum time.

10. Apparatus according to claim 9 in which said measuring means comprises:

a counter;

a digital-to-analog converter having an input electrically connected to said counter and an output whereby said output provides an analog signal corresponding to the count of said counter;

a comparator having first and second inputs and an output;

said first input being adapted to be electrically connected to said battery;

said second input being electrically connected to the output of said digital-to-analog converter; and

measuring-means pulse-generator means having an input and an output for applying series of pulses to its output when a predetermined potential is applied to its input;

said input of said measuring-means pulse-generator means being electrically connected to the output of said comparator and said output of said measuring-means pulse-generator means being electrically connected to the input of said counter.

11. Apparatus according to claim 10 in which:

said measuring means includes means for determining in which of a plurality of ranges of energy levels said battery is at the start of a charging run; and

said switch means includes a means for selectively reducing the rate of charging of the battery at a first maximum time when the energy level at the start of the charging run is in a first of said ranges and at said second time when the energy level at the start of the charging run is in a second of said ranges.

12. Apparatus according to claim 11 in which said means for determining in which of a plurality of ranges of energy levels said battery is comprises means for determining if the potential of said battery has a predetermined amplitude within a predetermined period of time from the start of a charging run.

13. Apparatus according to claim 12 in which said timer means comprises:

a timer counter;

said timer counter having an input and at least one output;

timer pulse-generator means for generating a plurality of pulses;

said timer pulse-generator means being electrically connected to the input of said timer counter, whereby a signal on the output of said timer counter indicates the time from the last output signal from said comparator to said measuring means.

14. Apparatus according to claim 13 further comprising:

battery charger means for applying a regular charge to said battery;

said timer counter including a first output terminal and a second output terminal;

said means for determining includes means for de-energizing said battery charger means when said timer counter applies a pulse to said first output terminal if said energy level is in said first range at the start of the charging run and when said timer counter applies a pulse to said second output terminal if said energy level is in said second range at the start of the charging run.

15. Apparatus according to claim 9 in which:

said measuring means includes means for determining in which of a plurality of predetermined ranges of energy levels said battery is at the start of a charging run; and

said switch means includes a means for selectively reducing the rate of charging of the battery at a first maximum time when the energy level at the start of the charging run is in a first of said ranges and at a second time when the energy level at the start of the charging run is in a second of said energy ranges.

16. Apparatus according to claim 15 which said switch means comprises:

a timer counter;

said timer counter having an input and at least one output;

pulse generator means for generating a plurality of pulses;

said pulse generator means being electrically connected to the input of said counter; and

the output of said counter providing at least one timing signal.

17. Apparatus according to claim 16 in which said timer counter includes two outputs and means for connecting a first of said outputs to said means for reducing when the energy level at the start of the charging run is in a first of said ranges and for connecting a second of said outputs to said means for reducing when the energy level at the start of the charging run is in a second of said ranges.

18. Apparatus according to claim 9 in which:

said measuring means includes a counter;

said apparatus further including an over-voltage protection means for actuating said switch means when a predetermined maximum battery potential is achieved;

one output of said counter being electrically connected to said over-voltage protection means.

19. Apparatus according to claim 18 in which said measuring means further comprises:

a digital-to-analog converter having an input electrically connected to said counter and to an output, whereby said output provides an analog signal corresponding to the count of said counter;

a comparator having first and second inputs and an output;

said first input being adapted to be electrically connected to said battery;

said second input being electrically connected to the output of said digital-to-analog converter; and

pulse generator means having an input and an output for generating a series of pulses when a predetermined potential is applied to its input;

said input of said pulse generator means being electrically connected to the output of said comparator and said output of said pulse generator means being electrically connected to the input of said counter.