Battery tester with power limit detection

• US 5,818,234 A
• Filed: 05/08/1996
• Issued: 10/06/1998
• Est. Priority Date: 05/08/1996
• Status: Expired due to Fees

• Current Assignee: Ferret Instruments Incorporated
• Original Assignee: Ferret Instruments Incorporated
• Inventors: McKinnon, Donald C.
• Primary Examiner(s): Oda, Christine K.
• Time in patent office: 881 Days
• Field of Search: 324/433, 324/435, 324/426, 324/142, 340/636, 340/455, 340/459, 340/461, 340/462, 340/661, 340/662, 340/664, 320/48
• US Class Current: 324/433
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382

Abstract

In an electrical resistive-load battery testing system, apparatus and methods are disclosed for independently monitoring and reacting to both the temperature of the load and the power actually consumed by the load. The signals derived by the temperature and power monitoring aspects of the invention may be used to provide visual and/or audible indicators to alert an operator that the system has exceeded predetermined operating levels. The load may be of a carbon-pile construction, though other loading arrangements are possible. According to the direct load-power monitoring aspect of the invention, electrical circuity is used to generate a signal representative of the power consumed by the load as a function of the voltage applied across the load and the current through by the load during the test, and a function such as an operator alert is performed in response to the power consumed by the load.

Claims

1. In a battery testing system wherein a battery is placed across a load having a power level rating to perform a test on the battery, the system including means for sensing the voltage developed across and means for sensing the current through the load during the test, the improvement comprising:

electrical circuitry operative to generate a signal representative of the power consumed by the load as a function of the voltage and current during the test; and

an indicator that signals to the system operator when the power consumed by the load exceeds the rating.

2. The battery testing system of claim 1, wherein the electrical circuity to generate a signal representating the power consumed by the load uses analog circuit techniques.

3. The battery testing system of claim 1, wherein the electrical circuity to generate a signal representing the power consumed by the load uses digital circuit techniques.

5. The battery testing system of claim 1, including one or more substantially linear load lines, each approximating a different portion of the curve associated with the power-level rating of the load.

6. The battery testing system of claim 5, wherein each load line is generated using one or more summing amplifiers in electrical communication with the load, each amplifier sensing the sum of the voltage and current being applied to the load by the battery.

7. The battery testing system of claim 6, wherein the load has two terminals to which the battery is coupled, and wherein each summing amplifier further comprises:

a first resistor connected to one of the terminals, the value of the first resistor being chosen to sense a nominal voltage within a predetermined range; and

a second resistor connected to the other of the terminals to sense current from the shunt voltage of the attached cable.

8. The battery testing system of claim 7, including a plurality of summing amplifiers cooperating to establish a set of overlapping load lines to approximate a boundary of power associated with the power level rating.

4. In a battery testing system wherein a battery is placed across a load to perform a test on the battery, a load power monitoring system, comprising:

a load having a power level rating;

means for coupling the battery to the load to perform a test on the battery;

means for sensing the voltage developed across the load during the test;

means for sensing the current through the load during the test;

electrical circuitry to generate a signal representative of the power consumed by the load as a function of the voltage developed across the load and the current through the load during the test, the circuitry utilizing one or more segments that approximate a portion of a curve associated with the operating power-level of the load; and

an operator indicator responsive to the signal representative of the power consumed by the load.

9. A method of monitoring power consumed by a load in a battery testing system, comprising the steps of:

connecting a battery across the load to perform a test;

sensing the voltage across the load during the test;

sensing the current through the load during the test;

determining the continuous power consumed by the load as the product of the voltage across the load and the current through the load;

providing a monitoring signal as a function of the determined power level.