Patent ID: 6242891
Filing Date: 2001-06-05
Classification: G01R

Abstract:
A battery charge monitoring means for deriving an indication of the state of charge of a defined type of battery, the monitoring means having:means for sensing a load voltage proportional to current flowing when a defined type of battery is connected to a load,a fixed reference voltage which is less than the maximum voltage of the defined type of battery to which the monitoring means is to be connected,current sensing means capable of providing a voltage output proportional to the voltage drop within the defined type of battery when under load as a result of the internal resistance of the defined type of battery,means for sensing a dynamic reference voltage comprising the fixed reference voltage minus the voltage output of the current sensing means,comparison means capable of comparing (a) the load voltage and (b) the dynamic reference voltage, to provide an output indicative of the state of charge of the battery.