Tesla IPO Firing on All Cylinders Batteries [UPDATED]

Tesla Motors went public today in the first initial public offering from an American car company since Ford’s (F) in 1956. And already, its stock appears to have attracted a cult following.

Floated with an initial offering price of $17, shares in the company opened at $19 and closed at $23.89–up $6.89, or 40.5 percent. Not a surprise, really, since Tesla (TSLA) raised the size of the IPO to 13.3 million shares from 11.1 million shares yesterday, presumably because of strong interest in the offering from investors.

That Tesla hasn’t earned a dime since it was founded in 2003 and doesn’t expect to post a quarterly profit until at least 2012 doesn’t seem to have fazed investors, who are evidently quite impressed with the company’s $109,000 all-electric Roadster and the fact that it has managed to sell 1,063 of the vehicles in less than two years.

“A lot of people were puzzled about why we were going public without profits,” CEO Elon Musk said today. “The reason we are not profitable today is because we are in the midst of expanding with the Model S.”

The bet here, then, seems to be the promise of the S, the $50,000 electric sedan the company plans to bring to market in 2013. And that appears to be working out quite well for Tesla.