How will I know if my battery is fully charged? March 15, 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 How long does it take to fully charge my battery? My racket doesn't switch on, why? Will my racket warn me if the battery is low? My racket doesn't switch on, Why? How can I charge up the battery? Comments 0 comments Article is closed for comments.