BYD , the Chinese battery and electric carmaker backed by Warren Buffett, is seeking to raise up to US$1.8 billion in a follow-up stock flotation in Hong Kong. The Shenzhen-based electric vehicle maker aims to sell 50 million new shares in a price range of HK$273.5 (US$35.17) to HK$279.5 each, according to a term sheet seen by the South China Morning Post. That would represent a discount of 5.8 per cent to 7.8 per cent to the HK$296.60 closing price of its H-shares in Hong Kong on Friday. The new shares would begin trading on November 1 and represent about…