In 4-6 qt Dutch oven cook bacon and beef, half at a time, over medium heat until beef is browned. Drain fat. Return meat to pan. Reduce heat; add onions and half of garlic. Cook and stir till onion is tender.
Add undrained tomatoes, beans, and 1 Tbsp of chili powder. Bring to boiling; reduce heat. Simmer, covered, for 1 hour, stirring occasionally. Stir in remaining garlic, chili powder, and vinegar. Cook, covered, 1 hour. Add water to desired consistency. Season to taste. Top servings with cheese, oregano, and crumbled bacon if desired.