Sort, wash, then soak the beans in cold water for 30 mins. Remove any floating beans.
Change the water, and soak in cold water for another 30 mins.
Drain beans, then add them to a slow cooker. Add the sausages, the bay leaf and 5 1/2 cups of hot water.
Close the slow cooker, and cook on high for 3 hours.
After 3 hours, open the pan, and leave it on high, while you move to the next steps.
Season with salt and pepper, add the cumin, and the vinegar to the pan, and stir.
Meanwhile, add the bacon to a large skillet over medium to high heat, and let them cook until lightly browned.
Add the olive oil to the skillet, then the onions and sautée until the onions are transparent, 2-3 mins.
Add the garlic to the skillet, stir and sautée until fragrant and lightly golden.
Add the contents of the skillet into the beans, stir and cover again. Let it cook until desired thickness is reached - about 30 minutes to an hour.