Battery charger and method utilizing alternating DC charging current
First Claim
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1. A battery charger comprising:
- a battery charging circuit for providing a battery charging current for charging a battery, wherein said battery charging current circuit repeatedly measures the voltage of said battery while said battery is being charged by an AC input source which defines AC zero crossings and provides first charging cycles during charging while the battery voltage is less than VMAX plus 0.2 volts and second charging cycles after the battery voltage reaches VMAX plus 0.2 volts, wherein said first charging cycle comprises two DC charging current values each having a non-zero average values defining a maximum level charging current and a minimum level charging current, said maximum level charging current and a minimum level charging current alternated back and forth until said battery voltage reaches VMAX plus 0.2 volts, said maximum level charging current and a minimum level charging current selected to cause said battery to be at least partially charged during said first charging cycle at a voltage greater than VMAX, wherein VMAX is the maximum recommended charging voltage by the battery manufacturer, and said second charging cycle is initiated when the battery voltage is greater than VMAX plus 0.2 volts and continues charging at a constant voltage.
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Abstract
A battery charger is disclosed for use with various batteries, such as automotive and marine-type batteries. In accordance with an aspect of the invention, the charging current is alternated between non-zero DC charging current levels. By alternating the charging current between non-zero DC charging levels, the battery can be charged to a higher capacity (i.e., ampere hours) faster, thus reducing the charging time and at the same time allow the rating of the battery charger to be increased. In accordance with another important aspect of the invention, the technique for alternating the charging current can be implemented in both linear and switched-mode battery chargers.
35 Citations
9 Claims
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1. A battery charger comprising:
a battery charging circuit for providing a battery charging current for charging a battery, wherein said battery charging current circuit repeatedly measures the voltage of said battery while said battery is being charged by an AC input source which defines AC zero crossings and provides first charging cycles during charging while the battery voltage is less than VMAX plus 0.2 volts and second charging cycles after the battery voltage reaches VMAX plus 0.2 volts, wherein said first charging cycle comprises two DC charging current values each having a non-zero average values defining a maximum level charging current and a minimum level charging current, said maximum level charging current and a minimum level charging current alternated back and forth until said battery voltage reaches VMAX plus 0.2 volts, said maximum level charging current and a minimum level charging current selected to cause said battery to be at least partially charged during said first charging cycle at a voltage greater than VMAX, wherein VMAX is the maximum recommended charging voltage by the battery manufacturer, and said second charging cycle is initiated when the battery voltage is greater than VMAX plus 0.2 volts and continues charging at a constant voltage. - View Dependent Claims (2, 3, 4)
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5. A method for charging a battery during a fast charge mode comprising the steps of:
- (a) repeatedly measuring the voltage of a battery to be charged;
(b) charging said battery with alternating non-zero DC current values during said fast charging cycle until said battery voltage exceeds VMAX plus 0.2 volts, wherein said DC current values have a non-zero average values defining a maximum level charging current and a minimum level charging current, said maximum level charging current and a minimum level charging current alternated back and forth until said battery voltage reaches VMAX plus 0.2 volts, said DC charging current values are selected to cause said battery to be at least partially charged during said fast charging cycle at a voltage greater than VMAX, wherein VMAX is the maximum recommended charging voltage by the battery manufacturer (c) subsequently charging said battery with at a constant voltage. - View Dependent Claims (6)
- (a) repeatedly measuring the voltage of a battery to be charged;
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7. A battery charger comprising:
- a battery charging circuit which provides a plurality of selectable charging levels and further providing a fast charge mode, wherein in said fast charge mode, the battery charger alternates between two different DC charging currents, wherein said DC charging currents have a non-zero average values and define a maximum level charging current and a minimum level charging current, said maximum level charging current and said minimum level charging current alternated back and forth until said battery voltage exceeds VMAX plus 0.2 volts, and charges said battery at a constant voltage thereafter, said DC charging currents selected to cause said battery to be at least partially charged during said fast charging cycle at a voltage greater than VMAX, wherein VMAX is the maximum recommended charging voltage by the battery manufacture.
- View Dependent Claims (8, 9)
Specification