Battery discharge control system

• US 5,164,653 A
• Filed: 10/26/1990
• Issued: 11/17/1992
• Est. Priority Date: 10/26/1990
• Status: Expired due to Fees

• Current Assignee: C & D Charter Power Systems, Inc.
• Original Assignee: C & D Charter Power Systems, Inc.
• Inventors: Reem, James B.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Dougherty, Thomas M.
• Application Number:
  US07/604,140
• Time in Patent Office: 753 Days
• Field of Search: 320/13, 323/269, 323/297, 323/367
• US Class Current: 320/135
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• CPC Class Codes: H02J 7/00714 in response to battery charging or discharging current

Abstract

Apparatus for controlling rate of battery current discharge, comprising, variable means applying resistance load to the battery output, comparator means connected for defining and communicating a targeted battery discharge current level set point, sensor means connected for sensing the rate of current discharge from the battery, and connected to the comparator for comparing the actual battery discharge current rate to the targeted battery discharge current, and adjusting means connected to the variable means and operative responsively to the comparitor means for incrementally increasing or decreasing the resistive load in response to signals from the comparator means as to whether the battery discharge current exceeds the targeted current set point.

Claims

1. Apparatus for controlling rate of battery current discharge, comprising:

a. variable means applying resistance load to said battery output;

b. comparator means connected for defining and communicating a targeted battery discharge current level set point;

c. sensor means connected for sensing the rate of current discharge from said battery, and connected to said comparator for comparing the actual battery discharge current rate to said targeted battery discharge current, and

d. adjusting means connected to said variable means and operative responsively to said comparator means for incrementally increasing or decreasing said resistive load in response to signals from said comparator means as to whether said battery discharge current exceeds said targeted current set point;

wherein said means for incrementally increasing or decreasing resistive load connected to said battery further comprises;

e. binary counter means for maintaining a count of current steps of predetermined levels by which said discharge current rate differs from said set point and continuously providing output signal corresponding to said counted steps;

f. relay means, operative responsively to said output signal of said binary counter means, for actuating contactor means;

g. said contactor means being arranged for connecting said battery to a selected resistive load; and

h. a plurality of resistive loads adapted to be connected in varying combinations to said battery via said contactor means.

2. Apparatus of claim 1 wherein said resistive loads of said plurality are binary weighted.

3. A method for controlling current discharge rate from a lead-acid battery, comprising:

a. loading a plurality of binary counters with data representative of an initial counter set point indicative of a desired rate of current discharge;

b. connecting a preselected resistive load to said battery and thereby causing said battery to provide discharge current through said load;

c. comparing the rate at which said current is discharged by said battery to said desired rate of current discharge and computing the difference if any, there between;

such difference being designated a positive difference if said actual rate at which current is discharged is greater than said desired discharge rate but being designated as a negative discharge rate if said actual rate is less than said desired discharge rate;

d. computing said difference as a binary number or a binary difference;

e. progressively engaging additional resistive loads in binary-weighted incremental amounts corresponding to said binary difference until the battery discharge current through the resistive load is less than the desired rate of current discharge; and

f. cyclically repeating steps c through e as said binary discharges until the discharge current rate reaches the preselected desired level.

4. A method for controlling current discharge rate from a lead-acid battery, comprising:

e. loading a latch with data representative of an initial set point indicative of a desired rate of discharge current;

b. connecting a preselected resistive load to said battery thereby causing said battery to discharge current through said load;

c. connecting an amplifier in parallel with said preselected resistive load to amplify voltage across said resistive load;

d. providing output of said amplifier to an analog to digital convertor to count output voltage of said amplifier to a digital representation of preselected output voltage of battery discharge current passing through said digital resistive load;

e. comparing said representation of rate of battery discharge current to said desired rate of current discharge and providing an appropriate output signal indicative of equality or inequality of present and desired battery discharge currents;

f. progressively incrementing counters engaging additional resistive loads in binary-weighted incremental amounts until battery discharge current through said preselected resistive load equals said desired discharge current;

g. cyclically repeating steps c through f to monitor battery discharge current until battery discharge current is equal to desired discharge current.

5. A method for controlling lead-acid battery discharge current using digital integrated logic circuitry to engage and control a variable array of binary-weighted resistive loads through which said battery discharge current passes, comprising:

a. comparing a digital representation of a sensed battery discharge current to a digital representation of a desired rate of battery discharge current stored in a latch, and sending an output signal indicating the equality or inequality of said sensed battery discharge current and said desired battery discharge current to a plurality of counters;

b. maintaining or incrementing count of said counters;

c. sending output signals of a plurality of binary counters to inputs of respective inverting line driving gates thereby driving each said output signal through a respective zener diode;

d. sending each output of each zener diode to the inputs of respective solid state relays thereby energizing only those relays receiving the proper input signal;

e. energizing solid state relay switches receiving said proper input to change low current from said digital logic circuit to high circuit; and

f. sending high current from energized solid state relay switching to respective mercury switches and thereby closing respective mercury switches and decreasing resistive load.