Yes, a car battery can absolutely die from not being driven. This is a common issue, especially for vehicles that are parked for extended periods. The primary reason is parasitic drain, where various electronic components (like the clock, security system, and onboard computers) draw a small but constant amount of power even when the car is off. Over weeks or months, this drain depletes the battery. Furthermore, lead-acid batteries naturally self-discharge. A deeply discharged battery can suffer from sulfation, a condition where sulfate crystals form on the battery plates, permanently reducing its capacity and ability to hold a charge.
To prevent this, the best solution is to use a battery maintainer (also called a trickle charger). This device plugs into a wall outlet and connects to your battery's terminals, providing a small, steady charge to counteract parasitic drain and self-discharge. If a maintainer isn't an option, starting the car and letting it run for at least 20-30 minutes once a week can help recharge the battery, but this is less effective than a dedicated maintainer for long-term storage.
The table below outlines typical power draws from common vehicle systems that contribute to battery drain:
| Parasitic Drain Source | Average Power Draw (Milliamps - mA) | Time to Drain a 50Ah Battery (Approx.) |
|---|
| Infotainment/ECU Memory | 20 - 50 mA | 40 - 100 days |
| Clock & Security System | 5 - 25 mA | 80 - 400 days |
| Keyless Entry System | 1 - 5 mA | 400 - 2000 days |
| Aftermarket Accessories (e.g., Dashcam) | 100 - 500 mA | 4 - 20 days |
| Total Acceptable Drain (Industry Standard) | < 50 mA | ~50 days |
For a vehicle parked for more than two weeks, taking preventive measures is highly recommended to avoid being stranded with a dead battery.
