Abstract: An onboard battery charging system including battery system and battery controller protection mechanisms and providing battery charge optimization where the protection portions of the system use an input isolation mechanism to isolate the vehicle power input from the battery controller upon detection of deviant charge voltages and a battery isolation mechanism to isolate the battery controller from the batteries upon detection of cyberattacks resulting in deviant charge power being provided to the batteries and where the charge optimization portions of the system use the same input isolation mechanisms as are employed for the vehicle system protection input isolation to regulate the timing of vehicle charging as a function of electricity prices.