Is it normal for a 12V battery to discharge to 11V?
2 Answers
The voltage of a 12V battery is not fixed and generally tends to be higher. Under normal circumstances, the battery voltage before starting the car is between 11.8V and 12.8V, and after starting, it ranges from 13.2V to 14.8V. As long as the voltage during startup is not lower than 11V, it is considered normal. Below are the standard voltage ranges for car batteries: 1. 12V systems: For 12V systems, the no-load voltage of the battery is around 13V, and a load voltage not lower than 11V is considered normal. Below this voltage, starting may become difficult. 2. 24V systems: For 24V systems, the no-load voltage of the battery is around 26V, and a load voltage not lower than 22V is considered normal. Below this voltage, starting may become difficult. 3. Generation standards: For 12V systems, the generator should produce a voltage between 13.5V and 14.5V when it starts generating power. For 24V systems, it should be between 27V and 29V. Generally, the operating voltage of a car battery is around 14-15V when running, 12V when parked, and if it drops below 11V when parked, starting the car may be difficult.
Actually, a 12V battery discharging to 11V isn't quite normal. Typically, vehicle startup requires at least 11.8V, and while driving the battery usually maintains around 13-14V. Dropping to 11V when the engine is off indicates the battery charge is already low. I've experienced this situation before - I could clearly feel the engine cranking slower during startup, and the dashboard lights were noticeably dimmer. This could be caused by battery aging reducing its charge retention capacity, or a loose alternator belt leading to insufficient charging. One winter I accidentally left the headlights on and discharged the battery to 11.5V, resulting in a completely dead battery the next morning that required jump-starting. I recommend using a charger to replenish the charge as soon as possible. Prolonged low voltage will shorten battery lifespan, and in severe cases, lead sulfate crystallization can permanently damage the plates.
