Control systems for battery chargers
First Claim
1. A control system for a battery charger including:
- means for switching on and off the charging current at repetitive intervals in order to provide a open circuit terminal voltage during the off periods;
means for providing a signal for controlling the magnitude of the charging current;
means for varying said signal between a maximum to provide maximum charging current and a minimum to provide minimum charging current;
means for extracting the resultant I.R. Drop at the battery terminals;
means for differentiating the rate of decay of the open-circuit terminal voltage of the battery at the said repetitive intervals;
means for deriving a voltage from said differential during the repetitive intervals, said voltage being a function of gas generation;
means for utilizing said voltage derived from the differential to cause said control signal varying means to vary said control signal in order to progressively reduce the magnitude of the charging current once gas generation has commenced.
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Accused Products
Abstract
A battery charger control system in which the charging current is switched on and off at repetitive intervals, the open circuit terminal voltage during the "off" periods being utilized to provide a control signal in order to vary the magnitude of the charging current during the "on" periods. The control signal is derived by extracting the resultant "I.R. Drop" at the battery terminals once the charging current has been switched off and then differentiating the rate of decay of the open-circuit terminal voltage of the battery. A voltage is then derived from the differential and used in one of three ways to control the magnitude of the charging current in order to progressively reduce its magnitude once gas generation has been detected as a result of a significant differential occuring.
24 Citations
26 Claims
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1. A control system for a battery charger including:
- means for switching on and off the charging current at repetitive intervals in order to provide a open circuit terminal voltage during the off periods;
means for providing a signal for controlling the magnitude of the charging current;
means for varying said signal between a maximum to provide maximum charging current and a minimum to provide minimum charging current;
means for extracting the resultant I.R. Drop at the battery terminals;
means for differentiating the rate of decay of the open-circuit terminal voltage of the battery at the said repetitive intervals;
means for deriving a voltage from said differential during the repetitive intervals, said voltage being a function of gas generation;
means for utilizing said voltage derived from the differential to cause said control signal varying means to vary said control signal in order to progressively reduce the magnitude of the charging current once gas generation has commenced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
- means for switching on and off the charging current at repetitive intervals in order to provide a open circuit terminal voltage during the off periods;
Specification