Storage battery condition tester utilizing low load current
First Claim
1. A battery condition tester for a battery having positive and negative terminals, said battery condition tester comprising:
- means comprising a switching circuit for periodically switching on and off a low constant current load between said battery terminals through a first set of battery terminal contacts; and
means comprising a separate detection circuit including;
first amplifier means coupled to said positive and negative terminals through a second set of battery terminal contacts to amplify the AC component of the battery voltage resulting from the switched battery current;
means for providing a DC voltage derived from the AC component of switched battery voltage;
means for providing an output signal related to battery condition as determined by said DC voltage; and
indicator means adapted to provide a reading indicative of the value of the battery voltage under heavy load.
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Accused Products
Abstract
A condition tester for a storage battery that monitors the effect of internal battery resistance without drawing large currents. A switched load periodically draws a small current across the battery terminals. An AC voltage is produced at the battery terminals resulting from the oscillating current and the internal battery resistance. That small oscillating voltage is amplified, rectified and filtered to produce a DC voltage which depends upon the AC component. This DC voltage is subtracted from the nominal battery voltage and the difference is indicated by an appropriate meter. As the battery deteriorates its internal resistance increases causing the meter reading to decrease, thereby reflecting battery condition.
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Citations
15 Claims
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1. A battery condition tester for a battery having positive and negative terminals, said battery condition tester comprising:
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means comprising a switching circuit for periodically switching on and off a low constant current load between said battery terminals through a first set of battery terminal contacts; and means comprising a separate detection circuit including; first amplifier means coupled to said positive and negative terminals through a second set of battery terminal contacts to amplify the AC component of the battery voltage resulting from the switched battery current; means for providing a DC voltage derived from the AC component of switched battery voltage; means for providing an output signal related to battery condition as determined by said DC voltage; and indicator means adapted to provide a reading indicative of the value of the battery voltage under heavy load. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for testing battery condition, said method comprising the steps of:
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periodically switching a constant current load from a switching circuit on and off across the positive and negative terminals of the battery to switch battery current on and off; isolating the switching circuit from a detection circuit by using two sets of battery contacts; detecting the AC component of battery voltage resulting from the switched battery current; producing a DC voltage from the AC component of switched battery voltage, said DC voltage being representative of the condition of the battery; and providing a reading indicative of the value of the battery voltage under heavy load by using said DC voltage. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification