The word "chariots" here represents the soldiers who drove the chariots. Alternate translation: "captain of half his chariot drivers" (See: [[rc://en/ta/man/jit/figs-metonymy]])
Being over the household represents being in charge of the things in King Elah's house. Alternate translation: "who was in charge of the things in the Elah's house" (See: [[rc://en/ta/man/jit/figs-metaphor]])