Electricity: measuring and testing – Electrolyte properties – Using a battery testing device
Patent
1981-08-26
1984-04-24
Tokar, Michael J.
Electricity: measuring and testing
Electrolyte properties
Using a battery testing device
324426, 324427, 320 48, 364481, 364483, G01N 2746
Patent
active
044450907
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates generally to voltage level monitoring and indicating apparatus and, more particularly, to apparatus for monitoring and indicating the discharge level of a battery.
2. Background Art
In a variety of systems, and for many reasons, it is important to have information or data concerning the voltage level or charge remaining in an energy storage device. For example, in a vehicle such as an electric lift truck, the voltage level or amount of charge remaining in the battery should be monitored and displayed to avoid potential problems. If the battery is used when it has been overly discharged, damage can occur to the battery as well as to electrical components such as motors and controllers that are supplied with power from the battery.
Electronic monitoring and display systems or apparatus have been developed to produce such information to avoid the problems resulting from an overly discharged battery. In one system, the instantaneous battery voltage is compared to a reference voltage. Whenever the instantaneous battery voltage is less than the reference voltage, an oscillator is turned on, whose pulses are counted by a counter. The counter outputs are fed to a digital-to-analog converter which drives the pointer of a gauge indicating the level of charge remaining in the battery. The output of the converter is also fed back to change the reference voltage. Thus, as the battery discharges, the counter is advanced, causing the converter to move the pointer on the gauge from a fully charged towards a fully discharged position and also to reduce the reference voltage.
One problem with the above monitoring and display systems relates to its application for use in state of the art vehicles. As the state of the art advances, these vehicles will have minicomputers including microprocessors to perform a number of functions. However, the prior monitoring and display system is not designed to be used with minicomputers and is expensive.
Furthermore, the prior monitoring and display system is a dedicated system in that it is designed or calibrated for use with a battery of one rated voltage, e.g., a 24 volt battery. A different design or calibration of the prior monitoring and display system would have to be implemented should it be used with, for example, a 36 volt battery. The requirement for two implementations enhances substantially the cost for producing a monitoring and display system for use with different batteries supplying different voltages.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a voltage level monitoring and indicating apparatus includes means for displaying data representing a voltage level. The improvement comprises a voltage-to-frequency converter having an input and an output and being constructed to produce a pulse frequency signal at the output proportional to a voltage signal at the input, and means for controlling the displaying means in response to the pulse frequency signal.
Means is included to receive a first voltage signal from a first voltage source or a second different voltage signal from a second different voltage source and to shift the first voltage signal and the second voltage signal to the same level and to supply the level shifted first voltage signal or the level shifted second different voltage signal to said input.
Prior voltage level monitoring and display systems are not minicomputer or microprocessor based systems and each design is dedicated to only one energy storage device. The present invention includes a microprocessor based voltage level monitoring and indicating apparatus and has a single design of a converter that can be used in connection with different energy storage devices.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an embodiment of the present invention.
FIG. 2A, FIG. 2B, FIG. 3 and FIG. 4. show flow charts of software used in the present invention.
BEST MODE FOR CA
REFERENCES:
patent: 2958823 (1960-11-01), Rabier
patent: 4322685 (1982-03-01), Frailing et al.
Principles of Electronic Instrumentation, A. James Diefenderfer, W. B. Saunders Co., Philadelphia, 1979, pp. 326, 327.
Curtis 933 Service Manual (Preliminary).
Blight Steven E.
Melocik Grant C.
Noe Stephen L.
O'Shea Kevin D.
Tokar Michael J.
Towmotor Corporation
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