What is normal voltage for a fully charged car battery?

What is normal voltage for a fully charged car battery?

• A. About 11.0 volts
• B. About 12.0 volts
• C. About 14.0 volts
• D. About 12.6 volts

Answer: (D)

A fully charged 12-volt car battery should read about 12.6 volts when measured with a voltmeter with the engine off. This comes from the chemistry of a lead-acid battery, which has six cells in series, each delivering roughly 2.1 volts when fully charged. Multiply that by six and you get about 12.6 volts, which is why that value is considered the normal resting voltage for a fully charged battery. If you measure while the engine is running, you’ll typically see the voltage climb to around 13.8 to 14.4 volts as the alternator charges the battery; that is not the resting voltage of a fully charged battery. The other readings (around 11.0 volts or 14.0 volts) don’t reflect a stable, fully charged state under no load. So the best answer is about 12.6 volts.

A fully charged 12-volt car battery should read about 12.6 volts when measured with a voltmeter with the engine off. This comes from the chemistry of a lead-acid battery, which has six cells in series, each delivering roughly 2.1 volts when fully charged. Multiply that by six and you get about 12.6 volts, which is why that value is considered the normal resting voltage for a fully charged battery. If you measure while the engine is running, you’ll typically see the voltage climb to around 13.8 to 14.4 volts as the alternator charges the battery; that is not the resting voltage of a fully charged battery. The other readings (around 11.0 volts or 14.0 volts) don’t reflect a stable, fully charged state under no load. So the best answer is about 12.6 volts.