Methods, apparatus and systems are provided for determining a characteristic of an energy source. One exemplary method involves obtaining a measured current associated with the energy source using a current sensor and obtaining a measured voltage associated with the energy source. In response to identifying an absence of an anomalous condition of the current sensor based on the measured current, the method determines a current-compensated value for the characteristic based at least in part on the measured voltage and the measured current. In response to identifying the anomalous condition of the current sensor based on the measured current, the method determines an uncompensated value for the characteristic based at least in part on the measured voltage.