The problem of golf cart batteries failing to hold charge overnight is a common fault in daily use, mainly caused by battery aging, circuit failure, improper maintenance, and environmental factors, which leads to obvious power loss after overnight parking and affects normal use the next day. The most primary cause is battery performance aging and capacity attenuation. For lead-acid golf cart batteries that have been used for more than 1.5 years and lithium batteries used for more than 5 years, internal cell aging, electrolyte failure (lead-acid), and cell capacity inconsistency (lithium) will occur. The self-discharge rate of aging batteries increases sharply, resulting in 20–40% power loss after overnight placement, while new qualified batteries only lose less than 5% power overnight.

Circuit parasitic power consumption and short-circuit faults are important inducements for overnight power loss. Golf carts are equipped with multiple auxiliary electrical equipment such as controllers, LED lights, and power displays. If the circuit harness has aging leakage, loose wiring, or faulty controller standby power consumption, it will cause continuous tiny power consumption of the battery overnight. In particular, damp and rainy golf course environments easily cause water ingress and oxidation of wiring interfaces, forming micro-short circuits and accelerating power loss. Damaged battery switches and faulty anti-theft devices will also keep the circuit in standby power consumption state, leading to overnight power drainage. In addition, mismatched or faulty chargers will cause incomplete charging: although the charger displays full charge, the battery cell voltage is not fully saturated, and virtual power will automatically dissipate overnight, resulting in insufficient power the next day.

Improper daily maintenance and extreme environmental conditions will aggravate the overnight charge loss problem. Long-term deep discharge and untimely charging will cause battery vulcanization (lead-acid) and cell damage (lithium), reducing charge retention capacity. Parking in high-temperature outdoor environments in summer will accelerate battery molecular activity and self-discharge speed; low-temperature freezing environments in winter will reduce battery internal resistance and activity, leading to increased power loss. For lithium golf cart batteries, BMS system failure will cause abnormal cell balancing, individual cell voltage drop overnight, triggering the overall battery low-voltage protection and false power loss. To solve this problem, users need to regularly detect battery cell health, check circuit leakage faults, replace aging batteries in time, avoid long-term full-charge floating storage, and park golf carts in dry and constant-temperature environments. Standardized charging and maintenance can effectively restore the battery’s overnight charge retention capacity and extend the overall service life.