Most electric golf cars utilize a battery pack with four or more deep cycle batteries that can provide many years of service when properly maintained. However, as the batteries age the vehicle’s driving range may become noticeably shorter. Replacing with new batteries is expensive and may not always be necessary. In some cases it may not be the entire battery pack that is going bad; instead it may be one battery that is not keeping up with the rest of the pack and hurting performance.
Steps for Identifying a Bad Battery In Your Pack
Step 1: Fully Charge Your Battery Pack and Take Readings
Fully charge all the batteries and then check the specific gravity in each cell of each battery with a hydrometer and check open circuit voltages with a multi-meter. Use the battery manufacturer’s recommendations to determine if the readings show the battery pack is fully charged. If not fully charged, repeat the charge cycle to bring the state of charge of the pack up. This is called equalization charging and should be performed at least every 30 days. If after repeated charges the batteries begin to increase in specific gravity, the batteries may be sulfated from incomplete charging over time. To determine if the charger is operating properly, refer to the US Battery website for a charger diagnostic procedure.
2: Perform a Discharge Test
If the specific gravities indicate the batteries are fully charged (1.260 or higher in all cells) and the voltage readings are good on each battery, discharge the battery pack on the vehicle in question. This can be done using a golf car battery load tester or by driving the car until it begins to lose power. If using a golf car battery load tester, the runtime should be 50% of rating or higher for a serviceable battery pack.
3: Test And Find The Bad Battery
At the end of discharge, check the voltage of each battery in the pack. If one battery is significantly lower than the rest of the batteries in the pack, mark that battery as suspect.
4: What If All The Batteries Show Low Voltage?
If the runtime is less than 50% of rating and the test readings on all the batteries do not indicate a suspect battery, then the entire battery pack may be at the end of its service life.
Replacing Defective Batteries
Once a suspect battery in your golf car’s battery pack has been identified, it is acceptable to replace that battery with a new one if the suspect battery is less than six months old. If the battery is over six months old, it is best to replace it with a similar battery from your fleet that has a date within six months of the rest of the pack or replace the entire pack. It is not recommended to mix new batteries with old batteries in a battery pack. It will shorten the life of both the new and old batteries and will void the warranty on the new battery.
For more information on golf car batteries, run-time ratings, and maintenance tips to keep golf car batteries running longer, visit www.usbattery.com.
