Chinese electric car and battery maker BYD's nine-month car sales soared 50% year on year to almost 300,000 units, local reports said on Friday.

MidAmerican Energy Holdings, a unit of Warren Buffett's Berkshire Hathaway investment unit, has a stake in the carmaker, which has plans to sell its all-electric 'e6' car in the United States starting in 2010, Reuters noted.

Sales in September increased 88% to 44,000 cars, the China Securities Journal reported, quoting an unnamed company official.

The strong sales come as China's government has been encouraging local automakers to focus on more fuel efficient models and environmentally friendly technologies.