The first company to join downtown’s Los Angeles Cleantech Incubator is now the first of the portfolio companies to be acquired.

Electric vehicle charging station operator 350Green announced Thursday that it has been acquired by Car Charging Group for $5.2 million.

Car Charging Group, based in Miami Beach, installs and manages electric charging stations. The company says that with the acquisition of 350Green, it is now the largest provider of EV stations in the United States.

Ian Gardner, who led the transaction through investment bank Oracle Capital, said 350Green was looking to raise money when it began to receive acquisition offers. The company, he said, was an attractive buy because of its large network of EV stations through contracts with retailers such as Walgreens Co.

Car Charging Group, meanwhile, brought deeper pockets as a public company, trading as an over-the-counter stock.

“350Green enabled Car Charging Group to get access to the right places on very favorable terms,” said Gardner, who has taken a role as vice president of development at the incubator. “A critical component of winning in the long run is having the financing expertise and the relationships to ride it until it takes off. That’s one of the reasons we felt Car Charging Group was the best option.”

Since bringing on 350Group in 2011, L.A. Cleantech Incubator has created a portfolio of 15 companies.