Another recipe from 101 More Things to do With a Slow Cooker. I use whatever beans I have in the house, but the refried beans makes the soup a little thicker and less "watery". It's a good way to get more beans into your diet.
1 can (16 oz.) kidney beans
1 can (16 oz.) fat-free refried beans
1 can (15 oz.) black beans
1 can (14 oz.) vegetable broth
1 can (14.5 oz) diced stewed tomatoes, with liquid
1 medium onion, chopped (or 1/2 cup dried minced onion can be substituted)
3/4 cup chunky salsa
1 tsp. minced garlic
2 tsp. chili powder
1/4 tsp. cumin
Combine all ingredients in greased slow cooker. Cover and cook on low heat 6-8 hours.