Various embodiments of the present technology comprise a method and apparatus for determining a resistance value of a resistor in a battery system. In various embodiments, the apparatus comprises a sense resistor connected to a current sensor. The apparatus may be configured to compute a voltage-based RSOC value and a current-based RSOC value and extract a capacity value from each. Over time, the capacity values will diverge and the difference can be used to compute an actual value of the sense resistor.