Quiescent voltage sampling battery state of charge meter
First Claim
1. A method for indicating the state of charge of batteries in an electrical power system of the type in which charged batteries are discharged through a load during a discharge cycle and whereinthe discharge cycle includes quiescent intervals,the method including the steps of detecting a quiescent condition with substantially no current flow through the battery,precisely timing each quiescent condition for a predetermined interval of at least one tenth of a minute,and then taking a measurement of the battery terminal voltage at the end of the time interval to provide as indication of the battery charge condition which is a function of the voltage and a function of the time interval.
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Accused Products
Abstract
State of charge is determined for a battery during a quiescent interval with substantially no current flow through the battery by determining the quiescent time interval since the last substantial current flow through the battery, taking a rapid measurement of the battery terminal voltage, and relating the combination of these two measurements to known battery open circuit voltage recovery characteristics.
82 Citations
33 Claims
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1. A method for indicating the state of charge of batteries in an electrical power system of the type in which charged batteries are discharged through a load during a discharge cycle and wherein
the discharge cycle includes quiescent intervals, the method including the steps of detecting a quiescent condition with substantially no current flow through the battery, precisely timing each quiescent condition for a predetermined interval of at least one tenth of a minute, and then taking a measurement of the battery terminal voltage at the end of the time interval to provide as indication of the battery charge condition which is a function of the voltage and a function of the time interval.
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8. A battery state of charge indicator system for monitoring the condition of electrical storage batteries in an electrical power system of the type in which charged batteries are discharged during a discharge cycle to supply a variable load and then recharged in a charge cycle and in which before beginning a new discharge cycle, and in which,
the discharge cycle includes a plurality of quiescent intervals, said indicator system including means for detecting the quiescent condition when there is substantially no current flow through the batteries, a timing means connected to said quiescent condition detecting means and operable to begin timing a predetermind interval of at least one tenth of a minute each time the beginning of the quiescent condition is detected, said quiescent condition detecting means being operable to reset said timer upon the interruption of the quiescent condition, said quiescent condition detecting means being operable to cause said timing means to continue timing said interval while the quiescent condition continues until the timing of said interval is completed, a voltage sample and storage means connected to said timing means and arranged to be connected to measure the terminal voltage of at least one of the batteries in the power system being monitored, said timing means being operable upon the completion of the timing of said interval to actuate said sample and storage means, said sample and storage means being operable upon such actuation to take a measurement of the battery terminal voltage to provide an indication of the battery charge condition which is a function of the voltage and a function of the time interval.
- 29. A method for indicating the state of charge of a battery in an electrical power system of the type in which a charged battery is discharged through a load during a discharge cycle, the method including the following steps carried out during a quiescent interval with substantially no current flow through the battery, determining the quiescent time interval since the last substantial current flow through the battery when such interval is a minimum of one tenth of a minute, taking a rapid measurement of battery terminal voltage, and relating the combination of the time interval and voltage measurements to known battery open circuit voltage recovery characteristics to provide an indication of the state of charge of the battery.
Specification