Prepare a slow cooker with nonstick cooking spray. Unwrap ham and place flat side down in a large slow cooker.
Stir about half of the brown sugar into the pineapple juice. Drizzle the pineapple juice and maple syrup over the ham.
Cover and cook on low for 4 to 5 hours. Baste ham with a baster like this one using the juices from the bottom of the slow cooker.