This will vary with rider weight, rider style, course length and terrain. But the short answer is 36 holes. We do recommend that a top off charge of 30 to 40 minutes is given between 18 hole rounds. A 90kg rider has ridden his board 45 holes on a regulation course with many hills. As you know for the longevity of any battery it is best to get the bump charge in between rounds.
Each riders comfort level will be slightly different. We find that most golfers have a very short learning curve of a couple of holes to become competent with the GSC. We offer 4 speed settings and many safety features.