Battery charging control circuits
First Claim
1. In a battery charging control circuit for controlling the charging of a battery in which gassing can occur at some stage during charging, said circuit being of the type wherein the state of battery charge is assessed by measurement when the battery charging current is interrupted and including timing means operated during an interruption to time a period of time, voltage register means responsive to the end of said period to register the battery voltage, comparison means to compare the registered battery voltage with the battery voltage registered earlier during a previous interruption of charging current, and comparison responsive control means responsive to the result of the comparison to permit, prevent or modify the charging current thereafter applied to the connected battery, the improvement wherein said comparison responsive control means includes means responsive to a minimum between decreasing and increasing differences between compared registered voltages indicative of the onset of a gassing phase of the charging of the battery to modify the charging current to a level appropriate to charging of the battery while the battery is gassing.
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Abstract
An improvement in the battery charging control circuit of our co-pending Application Serial No. 400,001, and more particularly a new means for detecting the onset of gassing during the charging of a battery, such as lead-acid battery.
In the exemplary embodiment described in our co-pending Application Serial No. 400,001, the onset of gassing was assumed to be imminent upon the attainment of a particular battery cell voltage. The present invention provides an improved means for determining the true onset of gassing by recognition of a unique point in the temporal pattern of the differences between successive registered battery voltages as measured during interruptions of charging.
32 Citations
4 Claims
- 1. In a battery charging control circuit for controlling the charging of a battery in which gassing can occur at some stage during charging, said circuit being of the type wherein the state of battery charge is assessed by measurement when the battery charging current is interrupted and including timing means operated during an interruption to time a period of time, voltage register means responsive to the end of said period to register the battery voltage, comparison means to compare the registered battery voltage with the battery voltage registered earlier during a previous interruption of charging current, and comparison responsive control means responsive to the result of the comparison to permit, prevent or modify the charging current thereafter applied to the connected battery, the improvement wherein said comparison responsive control means includes means responsive to a minimum between decreasing and increasing differences between compared registered voltages indicative of the onset of a gassing phase of the charging of the battery to modify the charging current to a level appropriate to charging of the battery while the battery is gassing.
Specification