Electronic battery testing device with state-of-charge compensation

• US 4,912,416 A
• Filed: 06/16/1989
• Issued: 03/27/1990
• Est. Priority Date: 06/06/1988
• 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): Harvey, Jack B.
• Time in patent office: 284 Days
• Field of Search: 324/426, 324/430, 324/433, 324/431, 324/436, 340/636, 320/48
• US Class Current: 324/430
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

A self-contained electronic device for testing storage batteries that may be partially discharged is disclosed. The testing device performs small-signal measurements of the 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 conduction based upon its electrical rating. In addition, the testing device measures the battery'"'"'s open-circuit (unloaded) voltage and provides adjustable means for correcting the dynamic conductance test result in inverse correspondence with the battery'"'"'s open-circuit voltage relative to its fully-charged value. By virtue of this correction, the quantitative or qualitative information displayed to the user in the dynamic conductance test is adjusted to comport with that of a fully-charged battery even through the battery may, in actual fact, be only partially charged when tested.

Claims

1. A process for testing a partially charged electrochemical cell or battery having an open-circuit voltage and a dynamic conductance comprising the steps of:

a. determining the value of the open-circuit voltage;

b. generating a signal proportional to the dynamic conductance;

c. adjusting the signal level in inverse correspondence with the value of the open-circuit voltage relative to a fully-charged value; and

,

d. displaying the adjusted result.

2. A process as in claim 1 wherein the step of determining the value of the open-circuit voltage comprises measuring the open-circuit voltage value, and the step of adjusting the signal level comprises manually entering the measured open-circuit voltage value.

3. A process as in claim 1 wherein the step of displaying the adjusted result comprises displaying a particular one of a plurality of qualitative results selected in accordance with the magnitude of the adjusted signal level.

4. A process as in claim 3 wherein the cell or battery has an electrical rating, including the step of manually adjusting the signal level in accordance with the electrical rating.

5. A process as in claim 1 wherein the step of displaying the adjusted result comprises displaying a numerical result proportional to the magnitude of the adjusted signal level.

6. A process for testing a partially charged electrochemical cell or battery having an open-circuit voltage and a dynamic conductance comprising the steps of:

a. measuring the open-circuit voltage;

b. measuring the dynamic conductance;

c. adjusting the measured dynamic conductance in inverse correspondence with the measured open-circuit voltage relative to a fully-charged value; and

,

d. displaying the adjusted result.

7. A process as in claim 6 wherein the step of adjusting the measured dynamic conductance comprises manually entering the measured open-circuit voltage.

8. A process as in claim 6 wherein the step of displaying the adjusted result comprises displaying a particular one of a plurality of qualitative results selected in accordance with the magnitude of the adjusted dynamic conductance.

9. A process as in claim 8 wherein the cell or battery has an electrical rating, including the step of manually adjusting the measured dynamic conductance in accordance with the electrical rating.

10. A process as in claim 6 wherein the step of displaying the adjusted result comprises displaying a numerical result proportional to the magnitude of the adjusted dynamic conductance.