Heat the olive oil in a large skillet over medium heat until hot.
Add garlic, onion and celery; cook until softened. Add bell pepper and chili powder; cook for 3 minutes.
Transfer mixture to a crock cooker then add remaining ingredients (tomatoes through black pepper). Cover and cook on HIGH for 6 hours or on LOW for 8 hours, or until ham is fork-tender. Slice ham before serving.