A ballast (e.g. a fluorescent light ballast) includes a primary ballast for powering the lamp from a power supply (e.g., utility line power) and an battery powered ballast for powering the lamp from a battery when the primary power supply is not energized by the power supply. When power supply power is restored to the ballast, the ballast shuts down the battery powered ballast and a switch circuit operably connects the lamp to the primary ballast. The ballast toggles the switch circuit such that the primary ballast detects replacement of a lamp and resets any fault detection or protection circuits (e.g., an end of lamp life circuit) that may have been triggered during the transition from battery power to power from the power supply.