Method and apparatus to monitor on-vehicle battery charger

A method for monitoring an on-vehicle battery charger includes estimating a charging efficiency of the battery charger. Upon achieving an indeterminate result related to the estimated charging efficiency of the battery charger, a commanded input power to the battery charger and an electric power at the on-vehicle battery during operation of the battery charger are determined. Flow of electric current through the battery charger is interrupted, and electric power flow from the on-vehicle battery is determined. An active charging efficiency of the battery charger is determined based upon the commanded input power to the battery charger, the electric power at the on-vehicle battery during operation of the battery charger and the monitored electric power flow from the on-vehicle battery when the flow of electric current through the battery charger is interrupted. Charging performance of the battery charger is evaluated based upon the active charging efficiency. 种监控车载电池充电器的方法，其包括估算电池充电器的充电效率。在获得与电池充电器的估算的充电效率相关的不确