For a typical 12-volt lead-acid car battery, a voltage below 12.4 volts when the engine is off can indicate a partially discharged battery. A fully charged battery should ideally measure around 12.6 to 12.8 volts when not under load. If the voltage drops significantly below these levels, it may indicate a problem with the battery, such as sulfation, internal short circuits, or other issues that could affect its performance or lifespan. If you’re referring to a different type of battery or specific application, the acceptable voltage range may vary.

A car battery is typically considered dead or fully discharged when its voltage drops below 10.5 volts under load. At this voltage, the battery lacks the necessary energy to start the engine or power electrical components effectively. However, it’s essential to note that attempting to start a car with a battery at or below this voltage can cause damage to the battery and may require replacement. If your car battery consistently drops to this voltage, it’s a sign that it may need to be replaced.

Several signs can indicate a faulty starter in a vehicle:

1. Clicking noise: When you turn the key to start the engine, if you hear a clicking noise but the engine doesn’t turn over, it could indicate a problem with the starter solenoid or starter motor.
2. Grinding noise: If you hear a grinding noise when attempting to start the engine, it may suggest that the starter gear is not properly engaging with the flywheel.
3. Slow cranking: If the engine cranks slowly or struggles to start, it could be due to a weak starter motor drawing too much current or not functioning correctly.
4. Intermittent starting: Sometimes the starter may work intermittently, causing the engine to start inconsistently. This can indicate a failing starter motor or electrical issue.
5. Smoke or burning smell: If you notice smoke or a burning smell coming from the starter or engine compartment, it could indicate an overheating starter motor due to electrical issues or mechanical problems.
6. Visible damage: Inspecting the starter for visible damage, such as corrosion, worn-out components, or loose connections, can also indicate a problem.

If you experience any of these symptoms, it’s essential to have your vehicle inspected by a qualified mechanic to diagnose and address the issue promptly.