At What Voltage Can a Car Battery Not Start the Engine?
2 Answers
When the car battery voltage drops below 11 volts, the car cannot be started. Typically, car batteries operate at 12V. If the battery voltage is too low, there won't be sufficient starting current to power the starter motor. Without the starter motor functioning, the car won't ignite and thus cannot start. A car battery, also known as a storage battery, is a type of battery that works by converting chemical energy into electrical energy. The commonly referred-to car battery is a lead-acid battery, which is primarily made of lead and its oxides, with a sulfuric acid solution as the electrolyte. The normal service life of a car battery ranges from 1 to 8 years, largely depending on the vehicle's condition. Under normal circumstances where the vehicle's alternator recharges properly and there are no electrical leaks or grounding issues, the battery can generally last more than 3 years.
I remember in my over 20 years of driving, when the battery voltage drops below 12.0 volts, the car usually won't start. Last winter was particularly cold, and my old car's voltage dropped to 11.9 volts. When I turned the key, all I heard was a click, and the engine didn't respond at all. In the end, I had to use jumper cables from my neighbor's car to get it going. Battery aging and low temperatures lower the starting threshold. A fully charged battery normally reads 12.6 volts, but when the voltage drops below 12.0 volts, the current isn't sufficient to meet the starter motor's demands. In winter, it's even more sensitive and can easily drop to around 11.8 volts. I recommend checking the battery voltage every quarter with a multimeter. If it's below 12.2 volts, pay attention—don't wait until it completely fails and causes trouble. Developing this habit can save a lot of hassle, as a failed start could cost you money in repairs.
