Tennis Tutor Jr Replacement Battery

Hi-

Does anyone on this forum happen to know the specifications for a suitable replacement battery for a Tennis Tutor Jr (aka Tennis Tutor Prolite)? Mine is on it's way out- and I'd rather pick up a replacement battery- perhaps something better than what Tennis Tutor would sell me- locally.

I believe that it uses a 12V, 7Ah lead acid battery.

Thanks!

TONY:)

The standard battery is around $50 or they have an external battery pack for $139. I have heard of users that have bought a Deep Cycle high AH 12V auto battery and adapting the connectors to mate to the JR. But that would have to be external of course.