A method includes receiving a first confidence level from a first battery sensor coupled to a first battery electrically coupled to an engine; receiving a second confidence level from a second battery sensor coupled to a second battery electrically coupled to the engine; storing the first confidence level and the second confidence level prior to the engine being powered off; receiving an updated first confidence level and an updated second confidence level after the engine is powered on; comparing (i) the first confidence level to the updated first confidence level for the first battery sensor and (ii) the second confidence level to the updated second confidence level for the second battery sensor; and enabling a stop-start functionality of the engine in response to the first confidence level and the second confidence level decreasing after the engine system is powered on relative to when the engine system was powered off.