Methods and systems are provided for monitoring a state of health (SOH) of a battery system of an electric vehicle (EV). A projected SOH value of the battery system at one of a future vehicle age and a future total EV mileage is generated. The projected SOH value is based in part on a current SOH value and historical SOH values associated with use of the battery system to supply power to at least one of an offboard vehicle load and an onboard accessory load. A determination is made regarding whether the projected SOH value is less than a SOH threshold at the one of the future vehicle age and the future total EV mileage. A customer SOH alert regarding use of the battery system to supply power to the at least one of the offboard vehicle load and the onboard accessory load is generated based on the determination.