VEHICLE BATTERY MONITORING ASSEMBLY AND MONITORING METHOD

A monitoring method includes, among other things, within an electrified vehicle, providing an accessory battery that is configured to power an electrical bus, and a traction battery that is configured to power the electrical bus. The method further includes loading the electrical bus with electrical loads of the electrified vehicle when an amount of power provided to the electrical bus by the traction battery is reduced. After the loading, the method compares an electrical parameter of the accessory battery to a threshold value to assess a condition of the accessory battery.