The industry standard is that 30 minutes of discharge time = 1 normal, 2-person, 18-hole round of golf.
The controlled conditions are these:
1). The battery pack is discharged at a rate equal to running the golf car at Wide Open Throttle.
2). The terrain conditions are level.
3). The battery temperature is 80 degrees F.
We then adjust the raw time to what it would have been had the batteries been at 80 degrees F. (run time is extended at temperatures above 80 degrees and reduced at temperatures below 80 degrees).
The result of the test is a “discharge minutes” reading on a particular set of batteries, such as 90 minutes, or 20 minutes, for example. This number represents the amount of time this particular battery pack would run, at wide open throttle on level ground, at 80 degrees.
In other words, a battery pack with a 60-minute discharge rating will usually run two rounds (36 holes) of golf before the pack needs to be re-charged. A pack that is rated at 15 minutes would normally play a 9-hole round; a 105-minute pack would play 3 18’s and a 9 before it would need to be re-charged, etc. Remember that the discharge test is run at “wide open throttle” with no letup. It certainly takes much longer than 30 minutes to play a normal 2-person 18-hole round. But think about how much time the golf car is being driven at wide-open throttle during the round, and understand that any time the golf car is stopped, the battery pack is given a “rest” and regenerates it self, raising the voltage in the battery during the time it is not under load.
Please know that these are measurements, not guarantees. Every round of golf is different, based on uphill or downhill terrain, weight of the riders, speed, distance between stops, and temperature, among other variables. The “30-minute rule” for one 2 person 18-hole round is an average, but it is used by golf courses to judge whether a golf car can be rented twice in one day, and by golf car manufacturers for warranty replacement purposes.