Any suggestions on how to get rid...

First, make sure you’re dealing with carpenter ants. If they are big and black, then they probably are carpenter ants. (You want to be sure you’re not dealing with termites.) Carpenter ants are usually seeking a source of water when they come into your home. They may head for leaky plumbing or a place where water pools from poor drainage or a roof leak. Make sure you’ve eliminated all faulty sources of moisture in your home. That should do the trick.