Electronic battery tester

• US 6,781,382 B2
• Filed: 12/05/2002
• Issued: 08/24/2004
• Est. Priority Date: 12/05/2002
• Status: Active Grant

• Current Assignee: Midtronics Incorporated
• Original Assignee: Midtronics Incorporated
• Inventors: Johnson, Frederick M.
• Primary Examiner(s): LUK, LAWRENCE W
• Application Number:
  US10/310,490
• Publication Number:
  US 20040108856A1
• Time in Patent Office: 628 Days
• Field of Search: 324/426, 324/433, 324/429, 320/132, 320/134, 320/155, 320/116, 320/119, 702/63
• US Class Current: 324/426
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/379 for lead-acid batteries

Abstract

An electronic battery tester for testing a storage battery is provided. The tester includes a pair of Kelvin connectors that can electrically couple to terminals of the battery. Also included, is a source that can apply a time varying forcing function to the battery through the Kelvin connectors. A sensor that electrically couples to the Kelvin connectors can sense a response of the storage battery to the applied forcing function and provide a response signal. An analog to digital converter digitizes the response signal. Processing circuitry converts the digitized response signal into multiple Fourier components and determines noise in the response signal from a subset of the multiple Fourier components.

Claims

1. An electronic battery tester for testing a storage battery, comprising:

a first Kelvin connector configured to electrically couple to a first terminal of the battery;

a second Kelvin connector configured to electrically couple to a second terminal of the battery;

a source configured to apply a time varying forcing function to the battery through a first conductor of the first Kelvin connector and a first conductor of the second Kelvin connector;

a sensor electrically coupled to a second conductor of the first Kelvin connector and a second conductor of the second Kelvin connector configured to sense a response of the storage battery to the applied forcing function and provide a response signal;

an analog to digital converter configured to digitize the response signal; and

processing circuitry configured to convert the digitized response signal into a plurality Fourier components, and to determine noise in the response signal from a subset of the plurality of Fourier components, and responsively provide an output related to presence or absence of noise in the response signal.

2. The apparatus of claim 1 wherein the at least one of the plurality of Fourier components is related to a frequency of the forcing function.

3. The apparatus of claim 1 wherein noise is determined using a Discrete Fourier Transform technique.

4. The apparatus of claim 1 wherein the forcing function comprises a load.

5. The apparatus of claim 1 wherein the forcing function comprises a current sink.

6. The apparatus of claim 1 wherein the sensor is configured to sense a voltage having a time varying component.

7. The apparatus of claim 1 wherein the sensor includes a differential amplifier.

8. The apparatus of claim 1 wherein the processing circuitry comprises a digital signal processor.

9. The apparatus of claim 1 wherein the processing circuitry comprises a microprocessor.

10. The apparatus of claim 1 wherein the forcing function comprises a square wave.

11. The apparatus of claim 1 wherein the processing circuitry is further configured to determine a dynamic parameter of the battery.

12. The apparatus of claim 11 wherein the dynamic parameter of the battery comprises conductance.

13. The apparatus of claim 11 wherein the dynamic parameter of the battery is selected from the group consisting of resistance, admittance and impedance.

14. The apparatus of claim 11 wherein the processing circuitry is further configured to determine battery capacity as a function of the dynamic parameter.

15. The apparatus of claim 1 wherein the processing circuitry is further configured to obtain a first battery capacity measurement as a function of peak-to-peak values of the response signal and peak-to-peak values of the forcing function, and to obtain a second battery capacity measurement as a function of the plurality of Fourier components, and to determine battery capacity as a function of the first battery capacity measurement and the second battery capacity measurement.

16. The apparatus of claim 15 wherein the battery capacity is provided at a tester output only if the difference between the first battery capacity measurement and the second battery capacity measurement is below an preset threshold.

17. A method of testing a battery, comprising:

applying a time varying forcing function to the battery through a first pair of connectors of a Kelvin connection;

sensing a response of the battery to the applied time varying forcing function through a second pair of connections of the Kelvin connection and providing a response signal;

digitizing the response signal;

converting the digitized response signal into a plurality of Fourier components;

determining noise in the response signal from a subset of the plurality of Fourier components; and

providing an output related to presence or absence of noise in the response signal.

18. The method of claim 17 wherein the at least one of the plurality of Fourier components is related to a frequency of the forcing function.

19. The method of claim 17 wherein noise is determined using a Discrete Fourier Transform technique.

20. The method of claim 17 further comprising obtaining a first battery capacity measurement as a function of peak-to-peak values of the response signal and peak-to-peak values of the forcing function, and obtaining a second battery capacity measurement as a function of the plurality of Fourier components, and determining battery capacity as a function of the first battery capacity measurement and the second battery capacity measurement.