Electronic battery testing device with automatic voltage scaling

• US 4,825,170 A
• Filed: 05/25/1988
• Issued: 04/25/1989
• Est. Priority Date: 05/25/1988
• Status: Expired due to Term

• Current Assignee: Keith S Champlin
• Original Assignee: Keith S Champlin
• Inventors: Champlin, Keith S.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Miele, Anthony L.
• Application Number:
  US07/198,484
• Time in Patent Office: 335 Days
• Field of Search: 324/426, 324/430, 324/436, 324/433, 320/48, 340/636
• US Class Current: 324/436
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

A self-contained electronic device for testing disparate storage batteries having any one of a fixed plurality of possible nominal voltages is disclosed. The testing device performs small-signal measurements of a battery'"'"'s dynamic conductance and provides either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery'"'"'s relative condition. Special voltage-sensing circuitry within the testing device identifies the particular one of the possible nominal voltages possessed by the battery and scales the dynamic conductance measurements accordingly. As a result, the quantitative or qualitative information provided to the user is automatically adjusted to comport with the nominal voltage of the battery undergoing test without the user having to actually input the battery'"'"'s nominal voltage to the testing device.

Claims

1. An electronic device for testing a direct current energy source having a dynamic conductance and a nominal voltage comprising:

a. means operably connected to said source for providing a signal proportional to said dynamic conductance;

b. means operably connected to said source for identifying said nominal voltage;

c. attenuator means responsive to said identified nominal voltage for scaling said signal; and

,

d. means for displaying a numerical quantity in response to the level of said scaled signal.

2. A device as in claim 1 wherein said numerical quantity is proportional to the level of said scaled signal.

3. A device as in claim 2 wherein said attenuator means scales said signal in proportion to said identified nominal voltage.

4. A device as in claim 2 wherein said attenuator means scales said signal in proportion to the square of said identified nominal voltage.

5. An electronic device for testing a direct current energy source having a dynamic conductance, a nominal voltage, and an electrical rating comprising:

a. means operably connected to said source for providing a signal proportional to said dynamic conductance;

b. means for manually adjusting the level of said signal in accordance with said electrical rating;

c. means operably connected to said source for identifying said nominal voltage;

d. attenuator means responsive to said identified nominal voltage for scaling said signal; and

,

e. means for displaying a qualitative assessment of said source in response to the level of said scaled signal.

6. A device as in claim 5 wherein said attenuator means scales said signal in proportion to the identified nominal voltage.

7. A device as in claim 5 wherein said attenuator means scales said signal in proportion to the square of said identified nominal voltage.

8. A system for displaying an assessment of a direct current supply having an internal resistance and a terminal voltage comprising:

a time-varying voltage source;

a time-varying current generating means, operably connected to both the voltage source and the supply, producing an output signal proportional to the time-varying voltage source and inversely proportional to the internal resistance;

selectable attenuator means interposed between the time-varying voltage source and the current generating means output,

voltage-sensing means operably connected to both the supply and the selectable attenuator means for selecting an attenuation value in response to the terminal voltage of the supply; and

,

means for sensing the current generating means output signal and for providing a display in response thereto.

9. A system according to claim 8 wherein said assessment comprises a quantitative assessment and said display comprises a numeric display.

10. A system according to claim 8 wherein said assessment comprises a qualitative assessment and said display comprises a display of at least two qualitative conditions.

11. A system according to claim 8 wherein said voltage-sensing means identifies a particular nominal voltage among a fixed plurality of possible values by a process which includes comparing a voltage derived from said terminal voltage with at least one reference voltage.

12. A system according to claim 11 wherein said selected attenuation value is inversely proportional to said particular nominal voltage.

13. A system according to claim 11 wherein said selected attenuation value is inversely proportional to the square of said particular nominal voltage.

14. An electronic device for testing a direct current supply possessing an internal resistance and a terminal voltage having one of two possible nominal values comprising:

a time-varying voltage source producing an input signal;

a time-varying current generating means, operably connected to both the voltage source and the supply, producing an output signal proportional to the input signal and inversely proportional to the internal resistance;

means for comparing a voltage derived from the terminal voltage with a reference voltage and attenuating the input signal by either of two attenuation values according to which voltage is greater;

means responsive to the output signal for producing an output display.

15. An electronic device according to claim 14 wherein the output display comprises a numerical display.

16. An electronic device according to claim 14 wherein the output display comprises a display of qualitative conditions.

17. An electronic device according to claim 16 wherein the supply has an electrical rating and the device includes means for manually adjusting the level of the output signal in accordance with the electrical rating.

18. An electronic device according to claim 14 wherein the ratio of the two attenuation values is the inverse ratio of the two nominal terminal voltage values.

19. An electronic device according to claim 14 wherein the ratio of the two attenuation values is the square of the inverse ratio of the two nominal terminal voltage values.