“Battery Discharge Ratings” for golf car batteries - Masek Golf Car Company
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“Battery Discharge Ratings” for golf car batteries

The industry standard is that 30 minutes of discharge time = 1 normal, 2-person, 18-hole round of golf.

The batteries are designed to operate in a very limited range: From “full charge” down to a minimum of 1.75V per cell, which we call “the cut-off point.”Running a flooded lead-acid battery down below 1.75V per cell will shorten its expected life of charge cycles. Therefore the cut-off point on a 36V battery pack (a total of 18 cells) is 31.5V. The cut-off point on a 48V pack (24 cells) is 42V. Modern golf cars with electronic speed controllers will normally not allow the car to run below its cut-off point. If voltage in the battery pack drops below its cut-off point the controller will normally shut the car down until the voltage comes back up above the cut-off point.

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.

Remember that the definition of “useful” varies: a golf course will normally replace a set of batteries if it cannot run 30 minutes of discharge time and cannot be rented for an 18-hole round of golf. That same battery pack, if in a personal car that only needs to run a nine-hole round before it gets charged, will still be “useful” if it has greater than a 15-minute discharge time. The objective of the BDS is to predict how much golf can be played between charge cyles with a particular battery pack. The higher the rating, the more energy the battery pack is capable of storing. Generally, we look for 60 minutes (36-hole performance) or better in the used battery packs we sell in our used golf cars for retail

For more information, please contact the golf car professionals at Masek Golf Car Co. 800-800-8987.