How much battery power is needed to start a car?

[KylieLynn]

In most cases, the vehicle can start normally when the load voltage exceeds 9.5V and the open-circuit voltage exceeds 11.5V. Below is relevant information: 1. Introduction to car batteries: A car battery, also known as a storage battery, is a type of battery that works by converting chemical energy into electrical energy. Typically, the term "battery" refers to a lead-acid battery, which is mainly made of lead and its oxides, with a sulfuric acid solution as the electrolyte. 2. Classification: Car batteries are divided into conventional batteries, dry-charged batteries, and maintenance-free batteries. 3. Maintenance: Car batteries should be charged regularly. If left unused for a long time, they will gradually self-discharge until they become unusable. Therefore, the car should be started periodically to charge the battery.

[StCody]

I've been driving for over a decade and have deep personal experience with car battery voltage. Typically, starting a car requires the battery voltage to be at least 12.4 volts, which corresponds to about 80% charge. If the voltage drops below 11.9 volts, the car usually won't start—you'll hear the starter clicking but the engine won't turn over, especially in winter when cold temperatures significantly reduce battery performance and increase demand. I recommend using a voltmeter to check the voltage when the engine is off; normally, it should read around 12.6 volts. Regular maintenance is crucial—for instance, don't let the battery age too much, as they typically need replacement every 3-5 years, otherwise power drains quickly. Carrying a portable jump starter is also a good habit to avoid emergencies. Additionally, high engine loads increase power demand, such as when trying to start the car with headlights on, which consumes more electricity. In short, maintaining battery health is key—don't wait until you're stranded to regret it.

[SanKing]

The voltage threshold for car starting battery, I often do DIY car repairs and know some tricks. The basic requirement is above 12.4 volts to start the engine, equivalent to 75% battery charge. If it drops below 10 volts, the engine absolutely won't start, and the starter will show no response at all. Measuring is simple, just use a multimeter connected to the battery terminals to get the reading. Temperature has a significant impact, summer is fine, but cold winter starts often require higher voltage, so it's best to give the battery a check-up before the cold season. For preventive measures, I often use a trickle charger to occasionally top up the charge, reduce deep discharges, and extend battery life. Additionally, if the lights dim or the engine cranks slowly, these are warning signs to address immediately without delay. Aging alternators in the car's system can indirectly cause insufficient battery charge, so regularly inspecting the entire electrical system helps prevent problems before they occur.

[DelSimon]

As a young car owner, I pay special attention to the battery when working on my car. The voltage needs to be around 12.4 volts to ensure normal engine startup; if it drops below 11 volts, it won't work. For checking, I usually use a mobile app connected to an OBD tool to read the data, which is super convenient. Cold weather makes it worse, as starting consumes more power, so keeping the voltage higher is necessary as a precaution. For regular maintenance, avoid draining the battery completely—for example, leaving the car unused for too long can cause discharge, but charging overnight can restore it. Aging batteries are prone to issues, so replace them promptly without delay.