Combine ground beef and onions in a large pot over medium heat; cook and stir until meat is browned and crumbly, about 5 minutes. Drain excess fat.

Add tomato juice, beans, tomato soup, potatoes, and chili powder. Stir in water and salt. Bring to a boil, then reduce heat to low and simmer until potatoes are tender and soup has thickened, about 1 hour.