At what voltage can a car battery no longer start the vehicle?

[LeSabrina]

When the car battery voltage drops below 10 volts, the vehicle can no longer be started. Generally, car batteries have a voltage of 12 volts, and when the voltage falls below 11 volts, the car will experience difficulty starting. A car battery, also known as an automotive battery, is primarily used for starting the vehicle and powering electronic systems such as lighting and audio. Car batteries are categorized into three types: conventional batteries, dry-charge batteries, and maintenance-free batteries. If the battery is undercharged or faulty, it can affect the normal starting of the vehicle. For daily maintenance, it is important to note: 1. When the car is not used for an extended period during winter, the battery should be removed to prevent discharge or damage due to freezing; 2. Regularly charge the battery, and the car should be started periodically.

[LaDallas]

I remember when I used to drive, once the battery voltage dropped below 11.8 volts, the car wouldn't start at all—the engine wouldn't even make a sound. Several winter mornings, I found myself stranded by the roadside. This happens because starting the engine requires a high current, and if the voltage is too low, the starter motor can't turn. I always carry a portable voltmeter to check the voltage. If it drops below 12.4 volts, I charge it in advance to avoid any inconvenience. I also keep an emergency jump starter in the car, which has come in handy a few times to help friends with similar issues. If the voltage remains too low for too long, not only will the car fail to start, but the battery could also suffer permanent damage. Replacing a new battery can cost hundreds of dollars, so it's better to be proactive—checking the voltage weekly can prevent such problems.

[McLogan]

I've driven several cars, and generally, the battery can start the engine smoothly when the voltage is above 12 volts, but it completely fails when it drops to 11.8 volts. Once, my car suddenly broke down when I was rushing to catch a flight for a business trip. Engine starting relies on stable current support; once the voltage drops, the starter loses power. Now, I'm used to monitoring the voltage via a mobile app connected to the OBD device in the car, checking the status regularly. Battery voltage fluctuates more dramatically with significant temperature changes, such as during summer heat or cold winter mornings. I usually park the car in a warm garage or let it warm up for a few minutes before starting in such conditions. Too low voltage can also affect onboard electronic systems like lights and navigation. It's advisable for car owners to invest in a smart charger for regular maintenance.

[DiGideon]

From my experience, a battery voltage below 11.8 volts basically can't start the car. The starter motor requires high current output during ignition, and insufficient voltage leads to weak current. It's slightly better in summer than winter, but once below that threshold, you need to charge or replace the battery. I always keep a multimeter in my car to test whenever there's ignition difficulty. Prevention is key—don't wait until a breakdown to take action.