Charge maintenance system for lead-acid battery

• US 6,441,584 B1
• Filed: 12/01/2000
• Issued: 08/27/2002
• Est. Priority Date: 12/02/1999
• Status: Expired due to Fees

• Current Assignee: Snap-On Technologies Incorporated (Snap-On Incorporated)
• Original Assignee: Snap-On Technologies Incorporated (Snap-On Incorporated)
• Inventors: Crass, Matthew M.
• Primary Examiner(s): Tso, Edward H.
• Assistant Examiner(s): TIBBITS, PIA FLORENCE
• Application Number:
  US09/729,253
• Time in Patent Office: 634 Days
• Field of Search: 320/129, 320/131, 320/132, 320/134
• US Class Current: 320/131
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A charge maintenance system for a lead-acid battery includes a charger, a voltage monitor, and a load/switch series combination, all connectable in parallel across the battery terminals, the switch and the charger being under control of a microprocessor. The battery is initially loaded for a predetermined time period, or until the battery voltage drops below an absolute minimum reference level during a loading cycle, and the system stores the lowest battery terminal voltage occurring during the loading cycle. After a predetermined delay following the loading cycle the charger is activated to charge the battery until it reaches a maximum charge level. Then, if the stored lowest battery voltage level is below a predetermined reference level, the loading/charging routine is repeated, otherwise it is not and the battery is considered good. If the stored lowest battery voltage level remains below the threshold for ten consecutive loading cycles, the system indicates that the battery failed the test but could be subject to retest. If the stored lowest battery voltage level is below an absolute minimum reference voltage level after three consecutive loading cycles, the system indicates that the battery is bad and should be discarded.

Claims

1. A battery testing and charge maintenance system for a lead-acid battery comprising:

a charger circuit adapted to be coupled to the battery,

a load and a switching device adapted to be connected in series across the battery,

a voltage monitor circuit adapted to be coupled to the battery for monitoring the terminal voltage thereof, and

a processor coupled to the charger circuit and to the switching device and to the monitor circuit and responsive to battery terminal voltage for controlling operation of the charger circuit and the switching device;

the processor operating under stored program control for subjecting the battery to at least one loading cycle with each loading cycle subsequent to a first loading cycle being preceded by a charging cycle until a predetermined battery voltage criterion is met.

2. The system of claim 1, wherein the processor includes a program routine which subjects the battery to alternate loading and charging cycles until at least one of plural battery voltage criteria is met.

3. The system of claim 2, wherein the program routine includes a portion establishing a first voltage criterion that the lowest battery terminal voltage occurring during the loading cycle is equal to or greater than a first predetermined reference voltage level.

4. The system of claim 3, wherein the program routine includes a portion establishing a second voltage criterion that the lowest battery terminal voltage occurring during a loading cycle has remained below the first predetermined reference voltage level for ten consecutive loading cycles.

5. The system of claim 3, wherein the program routine includes a portion establishing a third voltage criterion that the lowest battery terminal voltage occurring during a loading cycle is below a second predetermined voltage level after three consecutive loading cycles.

6. The system of claim 1, wherein the processor includes a timing program routine for establishing a predetermined time period for each loading cycle.

7. The system of claim 6, wherein the processor includes a program routine which maintains each loading cycle until expiration of the predetermined time period or until the battery terminal voltage drops below a predetermined absolute minimum voltage level, whichever occurs first.

8. The system of claim 1, wherein the processor includes a program routine having a timing portion which introduces a predetermined delay period between adjacent loading and charging cycles.

9. The system of claim 1, and further comprising a load indicator for indicating the status of the loading cycle and a battery condition indicator.

10. The system of claim 9, wherein the load indicator is operative during a loading cycle and indicates whether or not the battery terminal voltage has dropped below predetermined reference levels.

11. The system of claim 9, wherein the battery condition indicator is operative at the conclusion of a final charging cycle to indicate whether the battery (a) is good, (b) failed the cycling test but may be subject to further testing, or (c) should be discarded.

12. The system of claim 9, wherein the battery condition indicator is operative at the conclusion of a final charging cycle to indicate whether the battery (a) is good, or (b) should be discarded.

13. A method for maintaining and/or reconditioning a lead-acid battery comprising:

subjecting the battery to at least one loading cycle,

monitoring the battery terminal voltage during each loading cycle,

storing the lowest battery terminal voltage level occurring during each loading cycle,

subjecting the battery to a charging cycle prior to each loading cycle subsequent to a first loading cycle,

after each loading cycle comparing the stored lowest battery terminal voltage level during that loading cycle with at least one predetermined reference voltage level, and

determining, based on the results of each comparison, whether or not to subject the battery to further charging or loading cycles.

14. The method of claim 13, wherein the battery is subjected to a loading cycle for a predetermined time period.

15. The method of claim 14, wherein the loading cycle is maintained for the predetermined time period or until the battery terminal voltage drops below a predetermined absolute minimum voltage level, whichever occurs first.

16. The method of claim 13, wherein a loading cycle is not repeated if, as a result of the comparing step, the stored lowest battery terminal voltage level is equal to or greater than a first predetermined reference voltage level.

17. The method of claim 16, wherein a loading cycle is not repeated if, as a result of the comparing step, the stored lowest battery terminal voltage level has remained below the first predetermined reference voltage level for ten consecutive loading cycles.

18. The method of claim 16, wherein a loading cycle is not repeated if, as a result of the comparing step, the stored lowest battery terminal voltage level is below a second predetermined absolute minimum reference voltage level and the battery has been subjected to three consecutive loading cycles.

19. The method of claim 13, and further comprising providing a first indication of the state of the battery terminal voltage during a loading cycle and a second indication of the condition of the battery after a final charging cycle.

20. The method of claim 13, wherein the battery is subjected to a charging cycle after each loading cycle.