Rutgers Chabad is welcoming back students for the school year with the opening of the first Sephardi synagogue on an American public university campus, the latest component of its $13 million expansion.

Executive director Rabbi Yosef Carlebach also announced a drive to raise $3.6 million by early December to help pay off Chabad’s mortgage.

“It is our 36th — our double chai — year on this campus,” he said during a Sept. 3 interview at Chabad’s College Avenue offices on the university campus in New Brunswick. “We have never raised this amount of money in three months, but we wanted to make this year special.”

Expansion of the building, which was already the largest Chabad House in the world before the project, added 55,000 square feet to its existing 35,000-square-foot structure, opening in stages over almost two years. Starting with its banquet hall in December 2012, a new boys’ dorm was opened in spring 2013; a girls’ dorm had been operating for some years.

The Sephardi synagogue, which can hold up to 50 worshipers, opened in time for this semester with furniture made on Kibbutz Lavi in Israel. Elijah’s chair, set aside for the prophet at every bris in accordance with Sephardi tradition, was still wrapped in plastic during the Sept. 3 visit. Inside, a group of male students gathered for student-led Minha services.

The last remaining component of the expansion is a coffeehouse, which Carlebach said should be completed in 30-60 days.

The facility also includes three gyms, a mikva, a 500-seat dining hall, three elevators, and 50 showers.

“I never would have dreamed this 36 years ago, when we started in a little rented room on the fourth floor of the [Rutgers] student center,” said Carlebach. “Then we were trying to get enough students to hold a minyan.”

In 1981 it moved into its first building, becoming the only Jewish presence on campus other than Hillel, then located on the Douglass campus. In 1996, Chabad opened its current building, which immediately proved too small, said Carlebach.

Kosher meals are offered seven days a week; on Shabbat they are free. The evening before, on the first day of class, the dining hall had been packed with 400 students for an open house Israeli pride party.

“The place was rocking,” he said, adding the larger facilities provide a space “for Jewish students, both boys and girls, to be as Jewish as they want to be. Our goal is for students to leave with as much Judaism as they came in with, if not more.”

Chabad has rabbis on staff to meet the needs of both unaffiliated students and those with strong yeshiva backgrounds who seek advanced Jewish learning opportunities.

Even those outside the university have been attracted to the building. Its banquet hall is being booked for weddings and other celebrations. Because Carlebach, who is a state police chaplain, and his son, Rabbi Mendy Carlebach, a Rutgers Chabad administrator and a Port Authority of NY and NJ chaplain, have ties with law enforcement, Chabad recently hosted conferences involving state homeland security, FBI, and state police.

Students gathered at Chabad for lunch or to study, chat, or engage in a game of ping-pong, praised the facility.

Elisheva Greenblatt of Elizabeth said living in the Chabad dorm provides her with “a place where you can eat and pray. It’s a great place for students of all religious backgrounds to live and intermingle with each other. The programming is great. It’s like having social events with a religious factor,” said the junior who serves as a resident assistant.

Josh Herzfeld, a senior from Clifton and student copresident of Rutgers Chabad, said, “There’s a great atmosphere here. It’s fantastic how everyone is so friendly with each other and wants to help each other build a Jewish community.”