Canadian fuel cell maker Ballard Power Systems Inc posted a smaller-than-expected quarterly loss, helped by higher revenue from its engineering services and material handling businesses. Revenue from Ballard's engineering services business, which counts Volkswagen AG among its customers, rose nearly threefold in the first quarter ended March 31. The business accounted for half of Ballard's total revenue in the quarter. Ballard said it expected to begin supplying fuel cell stacks to service Plug Power Inc's order with Wal-Mart Stores Inc in the second half of this year. Plug Power said in February it would supply 1,738 hydrogen fuel cells, used to power forklifts and other material-handling equipment, to Wal-Mart.