With rolling pin or mortar and pestle, crack open cardamom pods to release seeds. In 4- to 5-quart slow cooker, place pods and seeds in.
Cut paper label from strings on tea bags; tie strings of bags to keep attached and place in cooker. Add remaining ingredients except syrup.
Cover; cook on High heat setting 3 hours.
Remove tea bags. Stir syrup into chai. Cover; cook 10 to 15 minutes longer or until thoroughly heated. Carefully ladle chai into cups, to avoid whole spices.