Aspects of the disclosure relate to a service port for an electrical power supply such as a battery. The service port may be an integrated pressure equalization and electrical probe port. In one or more implementations, the service port may include a housing have an open bore within which an electrical header is disposed. A gap may be provided between the electrical header and the housing to allow airflow though the service port into and/or out of an internal chamber of the electrical power supply for pressure equalization of the internal chamber. In one or more implementations, a breather element may be disposed in a distal end of the housing of the service port.