How will I know if my battery is fully charged? 15 March 2018 14:03 Updated Follow When you are charging the racket, the red light turns to green when the battery is fully charged. Related articles Will my racket warn me if the battery is low? How long does it take to fully charge my battery? My racket doesn't switch on, why? How can I charge up the battery? My racket doesn't charge up, Why? Comments 0 comments Article is closed for comments.