The booster club at the high school where I coach bought the team a Tennis Tutor (with the heavy-duty battery). However, they didn't realize that the charger was a separate item. I'm afraid that by the time I buy one from Tennis Tutor, the season will be over. Does anyone know what kind of charger would work with a Tennis Tutor? I have a son who works at a Radio Shack, and I was hoping to find something locally, and escape the delay in ordering one.