Signs you need new golf cart batteries include reduced run time, slow charging, frequent charging, low voltage, swollen batteries, excessive corrosion or leaks, and the batteries being over 4-6 years old.
To clean corrosion off golf cart battery terminals, disconnect the battery (negative first), scrub with a baking soda and water solution, rinse, and dry. Apply battery terminal protector or petroleum jelly to prevent future corrosion. Reconnect cables (positive first) and check monthly for buildup.
To store golf cart batteries in winter, fully charge them, check water levels, disconnect if not using a maintainer, and keep them in a cool, dry place above freezing. Use a battery maintainer or recharge every 4-6 weeks. Clean terminals and apply protection to prevent corrosion.