Soak beans overnight in slow cooker, add water to the top, the beans will triple in size. In the morning, drain the beans. Add ham, onion, maple syrup, brown sugar, and 3 cups of fresh water to the slow cooker.
Stir. Cook on low for 8 hours. Add ketchup, barbecue sauce, and mustard to bean, stir gently. Cook on low for 1 more hour.