(Adds BYD's H1 earnings forecast, share price)
BEIJING, April 25 (Reuters) - Chinese carmaker BYD Co Ltd , backed by U.S. billionaire Warren Buffett, sees first-half earnings up as much as 30 times on strong car sales and a big contribution from its cell phone unit.
In January-March, BYD's net income more than tripled to 112 million yuan, from 27 million yuan ($4.37 million) a year earlier, although 50.6 million of that was due to government subsidies, a stock exchange filing showed on Thursday.
The company said it expected to make 400-500 million yuan in the first half, up from 16.3 million yuan a year earlier, helped mostly by its new smartphone and flat-screen PC business.
In the first three months of 2013, BYD sold 142,851 cars, up 25.1 percent from a year earlier.
BYD's Hong Kong-listed shares closed down 4.4 percent at HK$25.2, before the release of quarterly earnings, underperforming a near 1 percent rise in the Hang Seng Index . ($1 = 6.1781 Chinese yuan) (Reporting by Hong Kong newsroom and Fang Yan in BEIJING; Editing by Kazunori Takada and Helen Massy-Beresford)