Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the pinto beans, black beans, kidney beans, diced tomatoes, barbecue sauce, chopped onion, chopped bell pepper, crumbled bacon, brown sugar, garlic powder, chili powder, and smoked paprika. Stir until well mixed.
Season the mixture with salt and pepper to taste.
Transfer the bean mixture to a 2-quart baking dish and spread it evenly.
Cover the dish with aluminum foil and bake in the preheated oven for 30 minutes.
Remove the foil and bake for an additional 15-20 minutes, until the beans are bubbly and slightly thickened.
Let the baked beans cool for a few minutes before serving.