Preheat your oven to 350°F (175°C).
In a large pot, cook chopped bacon until crispy.
Add diced onions and bell peppers; sauté until softened.
Stir in minced garlic and cook for another minute.
Add drained canned beans (pinto, kidney, and black beans).
Mix in barbecue sauce, ketchup, mustard, and brown sugar.
Season with salt, pepper, and chili powder to taste.
Transfer the mixture to a baking dish.
Bake uncovered for about 30-40 minutes until bubbly.
Let cool slightly before serving.