US Patent 9234943 Method and system for battery current measurement calibration

A sensor for monitoring battery current includes a shunt and a current source. The shunt has a resistance with an actual value. The current source is configured to provide a known value of current through the shunt. A controller is configured to generate a measured value of the current through the shunt as a function of a measured value of voltage drop across the shunt caused by the current through the shunt and an assumed value of the resistance of the shunt. The controller is further configured to detect the assumed value of the resistance of the shunt as being different than the actual value of the resistance of the shunt when the known and measured values of the current differ.