US 5,345,163 A · Battery monitoring system

Abstract

A battery monitoring method and apparatus are used for monitoring the charge level of a rechargeable electric storage battery, for example a lead acid battery. The counter-voltage of the battery is monitored by continuously monitoring the actual terminal voltage of the battery. When the battery is fully charged, the monitor provides a "DO NOT CHARGE" signal, for example a green light. When the charge level has dropped to a point that there may be some value in recharging the battery, the "DO NOT CHARGE" signal is replaced with an "OK TO CHARGE" signal, for example a yellow light. When the battery has discharged to the point where the battery must be recharged in order to avoid damage, the "OK TO CHARGE" signal is replaced with a "MUST CHARGE" signal, for example a red light. Audible signals may accompany the "OK TO CHARGE" and "MUST CHARGE" signals. The monitor is self-testing when turned on. It automatically recognizes the charge level of a battery to which it is connected. When used in association with, for example, a lift truck , the monitor may include a lift lock-out function that is engaged in response to the battery being discharged to the "MUST CHARGE" level.

Claims19

Dependent claims

A method of monitoring the charge on an electric storage battery having two terminals with a voltage across the terminals, said method comprising:

monitoring the voltage across the terminals of the battery;
producing a Do Not Charge signal whenever the monitored voltage exceeds a first predetermined voltage;
maintaining the Do Not Charge signal until the monitored voltage falls below the first predetermined voltage for a period longer than a first predetermined period, then eliminating the Do Not Charge signal and producing an OK To Charge signal;
and
maintaining the OK To Charge signal until the monitored voltage falls below a second predetermined voltage less than the first predetermined voltage for a period longer than a second predetermined period, then eliminating the OK To Charge signal and producing a Must Charge signal.

2 more elements

A battery monitor for monitoring the charge of a rechargeable electric storage battery having two terminals and a terminal voltage that is variable with battery charge and loads applied to the battery, the terminal voltage rising to a steady state counter voltage representing the battery charge over a recovery time interval after electrical loads are removed from the battery, said monitor comprising:

means for monitoring the terminal voltage;
first comparator means for comparing the monitored terminal voltage with a first predetermined value;
second comparator means for comparing the monitored terminal voltage with a second predetermined value less than the first predetermined value;
first indicator means for providing a Do Not Charge signal;
second indicator means for displaying an OK To Charge signal;
third indicator means for providing a Must Charge signal;
first time delay means connected to the first comparator means and to the first and second indicator means for maintaining the Do Not Charge signal and preventing the production of the OK To Charge signal until the monitored voltage of the battery has remained less than the first predetermined value for a first predetermined duration;
second time delay means connected to the second comparator means and to the second and third indicator means for maintaining the OK To Charge signal and preventing the production of the Must Charge signal until the monitored battery voltage has remained less than the second predetermined value for a second predetermined duration.

5 more elements

Dependencies are inferred from the claim text.

Battery monitoring system

Life of this patent

Battery monitoring system

Life of this patent

Abstract

Claims19