Battery charging has become a more complex task as power converters have continued to become more integrated. Earlier designs were stand-alone chargers whose only task was to charge a battery. Today battery chargers are expected to charge the battery and power the system in a safe manner. This topic presents battery-charging-system interactions and possible solutions when the system load is directly connected to the charge output. It also discusses the charger front end (CFE), a new safety trend for redundant protection with a high input-voltage rating for improving the charging system’s safety. In addition, two power-path-management topologies are presented that can power the system from the input while independently charging a battery. The selection process for these topologies is also discussed.