At What Voltage Will a Car Battery Fail to Start the Engine?

[LePaisley]

When the open-circuit voltage of a car battery drops below 12.2V and the load voltage falls below 9.5V, the vehicle will fail to start. Car owners should regularly inspect their car batteries by checking the observation window on the battery. If the window displays black, it indicates the need for charging; green signifies good condition; and white suggests insufficient electrolyte. Precautions for car battery usage: 1. Avoid powering devices alone after turning off the engine. To prolong battery life, minimize the use of in-car electronics when the engine is off. 2. Avoid excessive temperatures. Batteries are sensitive to cold, and low temperatures can reduce battery capacity, making it difficult to start the engine. However, excessive heat can be fatal to the battery.