A battery replaceable pack for a portable electronic device is provided. The battery replaceable pack includes a containing casing, at least one battery, a protecting circuit board, and a connector. The protecting circuit board has a charging circuit and a detecting circuit electrically connected with each other. When the portable electronic device is connected to an external power supply, the charging circuit performs a testing charge on the battery and the detecting circuit detects the status of the battery. The detecting circuit detects whether the battery is rechargeable so as to assure the battery safety. An electronic device with the battery replaceable pack is also disclosed.