A system includes an ultra-capacitor and battery system comprising a battery, a DC-DC converter, and an ultra-capacitor. An auto stop/start module is configured to perform an auto stop event of an engine of a vehicle and an auto start event of the engine of the vehicle based on operating parameters while an ignition is ON. A voltage monitoring module is configured to, in response to a request for an auto start event, selectively discharge the ultra-capacitor during cranking for the auto start event, accumulate a plurality of voltage delta values while the ultra-capacitor discharges during the cranking, and selectively disable the auto stop/start module based on the plurality of voltage delta values.