Leaving a car trunk open for 12 hours can drain the battery, but it depends on various factors. Here's a detailed explanation of the points:

Trunk Light Remains On Many cars have a small light inside the trunk that turns on when opened. If this light stays on for 12 hours, it can drain the car battery, especially if it is old or weak.

Battery Health: A well-maintained, healthy battery might handle the drain better and still have enough charge to start the car, but an older or weaker battery could die.

Power Consumption: Modern vehicles with electrical systems consume power even when not in use. If left open, the trunk can keep other electronics active, increasing battery consumption.

Cold Weather Impact: Batteries lose charge faster in colder weather. If the temperature is low, leaving the trunk open can worsen the situation and drain the battery more quickly.

Type of Lighting: If your trunk light is an LED, it consumes less power and may not drain the battery as quickly. Older cars with incandescent bulbs use more power, increasing the risk of a dead battery.

Automatic Shut-off Features: Some modern vehicles have automatic systems that shut off lights or other electronics after a certain period, preventing battery drain. If your car has this feature, it might save the battery.

Potential Warning Systems: Some cars may have a warning chime or indicator light to remind you to close the trunk, potentially preventing a long-term battery drain.

In summary, the likelihood of the battery dying depends on the battery's condition, the type of trunk light, and whether the car has any battery-saving features. If the battery is weak, it might not survive 12 hours with the trunk open.