Query based electronic battery tester

Abstract

An electronic battery tester for testing a storage battery provides a test output indicative of a condition of the battery. Electronic measurement circuitry provides a measurement output related to a condition of the battery. The battery condition is determined based upon one or more responses to one or more queries provided to an operator. The responses are used to determine battery type.

Description

BACKGROUND OF THE INVENTION

It is known that the condition of a battery can be provided by comparing a rating of the battery with a measured value. However, other techniques for providing a battery test could provide additional information regarding battery condition.

SUMMARY OF THE INVENTION

A method and apparatus for testing a storage battery provides a test output indicative of a condition of the battery. A condition of the battery is determined based upon at least one response of an operator to at least one query and a measured parameter of the battery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an electronic battery tester in accordance with the present invention.

FIG. 2 is a more detailed block diagram of the battery tester of FIG. 1.

FIG. 3 is a simplified flow chart showing steps in accordance with the present invention.

FIG. 4 is a diagram which illustrates various battery types.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a simplified block diagram of electronic battery tester 16 in accordance with the present invention. Apparatus 16 is shown coupled to battery 12 which includes a positive battery terminal 22 and a negative battery terminal 24. Battery 12 is a storage battery having a plurality of individual cells and a voltage such as 12.6 volts, 48 volts, etc.

FIG. 1 operates in accordance with the present invention and includes electronic test circuitry 2 which is configured to measure a parameter of battery 12 through first and second connections 8A and 8B. In one embodiment, circuitry 2 is dynamic parameter parameter measurement circuitry configured to measure a dynamic parameter of battery 12 through Kelvin connections 8A and 8B. Dynamic parameter measurement circuitry 2 can measure a dynamic parameter, that is a parameter which is a function of a signal with a time varying component, of battery 12 and provide a measurement output 4 to calculation circuitry 6. Example dynamic parameters include dynamic conductance, resistance, reactance, susceptance, and their combinations. Calculation circuitry 6 receives the dynamic parameter output 4. In some embodiments, circuitry applies a load test which may or may not also include measuring a dynamic parameter. In an load test, the Kelvin connections may not be required.

A memory 8 is coupled to calculation circuitry 6 and contains a plurality of user queries related to battery condition and a plurality of query relationships which relate to a response from a user to one or more queries and to the measurement output from the measurement circuitry 2. A query is provided to a user through query output 9 as explained in greater detail below. A query response is received from the user through query response input 13 and provided to calculation circuitry 6. Based upon the relationship stored in memory 8, the query response, and the measurement output 4, calculation circuitry 6 determines a battery condition. This condition is based upon at least one of the plurality of query relationships stored in memory 8. The query relationships can be in the form of a decision tree which identifies a particular battery type based upon the query response(s). he battery condition can also be a function of an optional battery rating received through an input, for example the same input 13 used to receive the query response. Calculation circuitry 6 provides a battery condition output 11. The output 11 can be output to other circuitry or displayed locally, for example on output 9.

In various aspects of the invention, the battery test output can be various relative or absolute indications of a battery's condition. The output can be pass/fail, percent charged related to battery state of health, capacity, or other output related to battery condition.

FIG. 2 is a more detailed block diagram of circuitry 16 which operates in accordance with one embodiment of the present invention and determines a dynamic parameter such as the conductance (G_BAT) of battery 12 and the voltage potential (V_BAT) between terminals 22 and 24 of battery 12. Circuitry 16 includes a forcing function (such as current source 50), differential amplifier 52, analog-to-digital converter 54 and microprocessor 56. In this embodiment, dynamic parameter measurement circuitry 2 shown in FIG. 1 generally comprises source 50, amplifier 52, analog to digital converter 54, amplifier 70 and microprocessor 56. Calculation circuitry 6 generally comprises microprocessor 56. The general blocks shown in FIG. 1 can be implemented as desired and are not limited to the configurations shown in FIG. 2. Amplifier 52 is illustrated as capacitively coupled to battery 12 through capacitors C₁ and C₂. Amplifier 52 has an output connected to an input of analog-to-digital converter 54. Microprocessor 56 is connected to system clock 58, memory 60, pass/fail indicator 62 and analog-to-digital converter 54. Microprocessor 56 is also capable of receiving an input from input device 66. The input can be the query response input 13, a rating of the battery, or other data as desired. Output 67 can be a local display for displaying queries, battery condition, etc.

In operation, current source 50 is controlled by microprocessor 56 and provides a current in the direction shown by the arrow in FIG. 2. This can be any type of time varying signal. Source 50 can be an active source or a passive source such as a resistance. Differential amplifier 52 is connected to terminals 22 and 24 of battery 12 through capacitors C₁ and C₂, respectively, and provides an output related to the voltage potential difference between terminals 22 and 24. In a preferred embodiment, amplifier 52 has a high input impedance. Circuitry 16 includes differential amplifier 70 having inverting and noninverting inputs connected to terminals 24 and 22, respectively. Amplifier 70 is connected to measure the open circuit potential voltage (VET) of battery 12 between terminals 22 and 24. The output of amplifier 70 is provided to analog-to-digital converter 54 such that the voltage across terminals 22 and 24 can be measured by microprocessor 56.

Circuitry 16 is connected to battery 12 through a four-point connection technique known as a Kelvin connection. This Kelvin connection allows current I to be injected into battery 12 through a first pair of terminals while the voltage V across the terminals 22 and 24 is measured by a second pair Kof connections. Because very little current flows through amplifier 52, the voltage drop across the inputs to amplifier 52 is substantially identical to the voltage drop across terminals 22 and 24 of battery 12. The Kelvin connections can be “split” and do not all need to be connected directly to the battery terminals 22 and 24. The output of differential amplifier 52 is converted to a digital format and is provided to microprocessor 56. Microprocessor 56 operates at a frequency determined by system clock 58 and in accordance with programming instructions stored in memory 60. Memory 60 can also store the relationship tree used to identify battery types.

Microprocessor 56 determines the conductance of battery 12 by applying a current pulse I using current source 50. This can be, for example, by selectively applying a load such as a resistance. The microprocessor determines the change in battery voltage due to the current pulse I using amplifier 52 and analog-to-digital converter 54. The value of current I generated by current source 50 is known and is stored in memory 60. In one embodiment, current I is obtained by applying a load to battery 12. Microprocessor 56 calculates the dynamic conductance of battery 12 using the following equation: $\begin{array}{cc}\mathrm{Conductance}=G_{\mathrm{BAT}}=\frac{\Delta I}{\Delta V}& \mathrm{Equation}1\end{array}$ where ΔI is the change in current flowing through battery 12 due to current source 50 and ΔV is the change in battery voltage due to applied current ΔI.

Microprocessor 56 operates in accordance with the present invention and determines a condition of battery 12 based upon a determination of the type of battery obtained through query responses. The data output can be a visual display or other device for providing information to an operator and/or can be an output provided to other circuitry.

FIG. 3 is a flow chart 100 showing operation of microprocessor 56 based upon programming instructions stored in memory 60. Block diagram 100 begins at start block 102. At block 104, a query is provided to the operator. This can be, for example, retrieved from memory 6. At block 106, the query response is obtained. At block 108, if the query response has not led to an identification of battery type, control is passed to block 104 and further query responses are obtained. Once the battery type is identified, control is passed to block 108 and the battery is tested at block 110 as a function of dynamic parameter and the determined battery type.

Some prior art battery testers have compared a battery measurement to a fixed value, such as a rating of the battery in order to provide a relative output. For example, by comparing a measured value of the battery with the rating of the battery, an output can be provided which is a percentage based upon a ratio of the measured value to the rated value. However, the present invention recognizes that in some instances it may be desirable to provide a battery test which is a function of battery type.

As used herein, a dynamic parameter of the battery is a parameter which has been measured using an applied signal (either passively or actively) with a time varying component. Example dynamic parameters include dynamic resistance, conductance, reactance, susceptance and there combinations both real, imaginary and combinations.

Based upon the measured dynamic parameter and the determined battery type, a test output is provided. Examples of a test outputs include an end of life prediction for the battery which can be in the form of months, seasons or other forms; a state of health or state of charge determination; a predicted number of engine starts of the vehicle which the battery can perform; a predicted number of charge and discharge cycles which the battery is capable of experiencing, a prediction of time to reach an end voltage based upon current draw and temperature; a predicted time to charge the battery based upon charge current and temperature; a prediction of the largest current at which a load test applied to the battery can be passed; a prediction of the reserve capacity of the battery; a prediction of the number of amp-hours remaining in the battery, or others.

The test output can be shown on a display, used to provide pass/fail information or passed along the other circuitry.

Battery tester 16 is configured to test a number of different types of storage batteries. The queries contained in memory 8 (or 60) can relate to questions which will yield answers from an operator which are indicative of a particular type of battery. For example, the circuitry 6 can query an operator with questions related to the presence, number, or configuration of vent caps present on a battery. The presence and location of any hoses connected to the battery, particular visible markings or colors of the battery, particular brand information of the battery, etc. Based upon the response to these queries, memory 8 contains a relationship tree which indicates a particular algorithm for use by calculation circuitry in testing the battery. For example, if the responses to the queries indicate that the battery is a flooded battery, the test algorithm which is selected may be different than if the query responses indicate that S the battery is a gel cell type battery. In general, such queries can be related to the physical construction of the battery which can be observed by an operator.

FIG. 4 is an example of a query decision tree which can be used to identify the type of battery under test. FIG. 4 illustrate two main trees, vented lead acid and sealed lead acid. Within each of these main trees are various subgroups of batteries. Through a-series of queries, such as what is the color of the battery, what descriptors are on the battery, does the battery have caps, what do the caps look like, is the liquid level within the battery visible, is there a “magic eye” visible on the battery, what type of brand labeling is present, what is the shape of the battery or cells within the battery, etc., the calculation circuitry 6 is able to walk through the decision tree shown in FIG. 4. As the operator responds to queries, the calculation circuitry 6 is able to specifically identify the type of battery under test. Once the particular battery type is determined, the calculation circuitry performed a test on the battery which is a function of the determined battery type. This allows the test to be tailored for the particular type of battery. An example of a user query is “Does the battery have vents?”, “Does the battery have caps?”, “Are the caps round or square?”, “What is the color of the battery case?”, etc. The user input can be, for example, selected from a number of options. The user input can be selected, for example, by touching the desired response on a screen, scrolling through the set of desired responses, pressing a button which is associated with the desired response, or other techniques.

The present invention may be implemented using any appropriate technique. For simplicity, a single technique has been illustrate herein. However, other techniques may be used including implementation in all analog circuitry. Additionally, by using appropriate techniques, any dynamic parameter can be measured. Further, in some embodiments, the test is not based on a dynamic parameter or is based on multiple parameters. With the present invention, a desired output level of the battery is obtained, for example through an input.

Various types of batteries include vented lead acid, sealed lead acid, vented lead acid, spiral, deep cycle, electrolyte gel cells, absorbed glass matt, valve regulated lead acid, Orbital brand, starting, lighting ignition batteries, Optima brand, sealed flooded, antimony, and hybrid. In one embodiment, if battery type cannot be determined, the battery tester will assume that it is a AGM battery type.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For example, date codes, weight, logos or other indicia can be used in identification. The tester can provide a graphical display to assist in the identification of battery type.

Claims

1. (canceled)

2-55. (canceled)

56. A method of performing a battery test using an electronic battery tester, comprising: connecting the electronic battery tester to a storage battery; receiving a query from the electronic battery tester regarding an observable physical characteristic of the battery; providing the electronic battery tester a response to the query related to the observerable physical characteristic; and receiving a battery test result from the electronic battery tester which is related to a measurement performed on the battery by the electronic battery tester and upon the response to the query.

57. The method of claim 56 wherein receiving a query comprises observing a display.

58. The method of claim 56 including retrieving the query from a memory.

59. The method of claim 56 wherein the measurement comprises a measurement of a dynamic parameter.

60. The method of claim 56 including coupling to the battery with Kelvin connection.

61. The method of claim 56 wherein the measurement is a function of an applied forcing function having a time varying signal.

62. The method of claim 56 including receiving a plurality of queries.

63. The method of claim 56 wherein the query relates to observable physical construction of the battery.

64. The method of claim 56 wherein the query relates to a shape of the battery.

65. The method of claim 56 wherein the query relates to a color of the battery.

66. The method of claim 56 wherein the query relates to caps on the battery.

67. The method of claim 56 wherein the query relates to a tube connected to the battery.

68. The method of claim 56 wherein the query relates to a visible liquid level of the battery.

69. The method of claim 56 wherein the query relates to a “magic eye” on the battery.

70. The method of claim 56 wherein the query relates to the brand label on the battery.

71. The method of claim 56 wherein the query relates to a battery type.

72. The method of claim 71 wherein the battery type comprises sealed lead acid.

73. The method of claim 71 wherein the battery type comprises vented lead acid.

74. The method of claim 71 wherein the battery type comprises spiral.

75. The method of claim 71 wherein the battery type comprises deep cycle.

76. The method of claim 71 wherein the battery type comprises an electrolyte gelatin.

77. The method of claim 71 wherein the battery type comprises an absorbed glass matt.

78. The method of claim 71 wherein the battery type comprises starting, lighting, ignition battery.

79. The method of claim 71 wherein the battery type comprises sealed flooded.

80. The method of claim 71 wherein the battery type comprises antimony.

81. The method of claim 71 wherein the battery type comprises hybrid.

82. The method of claim 56 wherein providing a responses comprises touching a desired response on a screen.

83. The method of claim 56 wherein providing a response comprises scrolling through a set of responses.

84. The method of claim 56 wherein providing a response comprises pressing a button.