Drain peppers, reserving 1 tablespoon liquid; chop peppers. Drain artichokes, reserving 2 tablespoons liquid; coarsely chop artichokes. , In a 3-qt. slow cooker coated with cooking spray, combine spinach, cheeses, basil, onion, mayonnaise, garlic, artichoke hearts and peppers. Stir in reserved pepper and artichoke liquids. Cook, covered, on high 2 hours., Stir dip; cook, covered, until cheese is melted, 30-60 minutes longer. Stir before serving; serve with crackers.,