Age of the Battery: Car batteries typically last 3 to 5 years, and their ability to hold a charge decreases with age.
Extended Inactivity: When a car is left unused, the battery continues to supply power to the electrical system, which weakens its charge over time.
Faulty Charging System: Issues with the charger, dynamo ampere, or alternator (including a loose or tight alternator belt) can result in improper charging, either undercharging or overcharging, which damages the battery.