Which of the following is a function of the Battery and External Power Junction Box (BEPJB)?

The function of the Battery and External Power Junction Box (BEPJB) is essential for managing the electrical power systems of the aircraft. Specifically, it plays a crucial role in providing external power to the batteries. This capability allows the aircraft to receive power from a ground source or external power unit when it is on the ramp or during maintenance, enabling the charging of onboard batteries and powering of electrical systems without running the engines.

The BEPJB effectively ensures that the aircraft's battery system remains charged and operational, which is critical for starting the engines and powering the aircraft's systems during flight. By facilitating external power access, it also enhances the safety and readiness of the aircraft by ensuring that critical electrical systems function as intended before flight. Other options do not appropriately align with the primary role of the BEPJB in power management.