# What Voltage Is A Battery Dead?

## Why does a dead battery still have voltage?

In general, the more surface area the chemicals have to deposit charge onto, and take charge away from, the higher the current the battery can produce.

A nearly dead battery still provides 1.5 volts, but has a very high internal resistance so that drawing even a trickle of current zeros out the voltage gain..

## Is 12.4 volts OK car battery?

A car battery is considered fully charged at 12.6 volts or higher. When the battery’s voltage drops, even a small amount, it makes a big difference in its performance. … Though not fully charged, a car battery is considered charged at 12.4 volts or higher. It is considered discharged at 12.39 volts or less.

## What is the voltage of a dead 12 volt battery?

Resting fully charged 12-volt batteries are around 12.8-12.9 volts, and flat dead ones are at 12.0 volts, so 12.4 volts on a resting battery means it’s about 50% charged.

## What voltage is a dead car battery?

A reading of 12.65-12.77 volts means your battery has a full charge. 12.45-12.54 volts means you have a 75% charge, 12.24-12.29 is 50% charged, and 11.99-12.06 volts is 25% charged. 11.75-11.89 volts means your battery is dead.

## How can I tell if my 12v battery is bad?

If your battery is reading 0 volts, chances are the battery experienced a short circuit. If the battery cannot reach higher than 10.5 volts when being charged, then the battery has a dead cell. If the battery is fully charged (according to the battery charger) but the voltage is 12.5 or less, the battery is sulfated.

## At what voltage will a car not start?

The maximum range would be around 12.9-Volts, which only seem a concern when they get to about 13-Volts. The voltage range of 13-Volts battery and above is usually the typical range once the battery gives current over to the alternator of the vehicle – acceptable under these conditions.

A voltmeter is the most reliable way to determine if a battery is holding its charge. … If the voltmeter shows no reading or a reading below 12.4 volts, the battery is dying. If the voltmeter reads 12.4 volts or higher, the battery is fine and the problem lies elsewhere. Start your car.

## Is 11.9 volts enough to start a car?

However, in practice, the normal voltage for most of the passenger cars can be in the range of 12.2-12.49V, which indicates an incomplete charge. A decrease in performance and the quality of the device begins in the case of reduction to 11.9V or less.

## Can a car battery be recharged from dead?

While your vehicle’s alternator can keep a healthy battery charged, it was never designed to completely recharge a dead car battery. … These charging devices are designed to safely restore a dead battery to full charge. Most of the time, you don’t even have to remove the battery from your vehicle.

## Is 10 volts enough to start a car?

A: Car battery voltage will change depending on its condition. When the engine is off the battery open circuit voltage is 12.9 volts. … As the battery discharges the voltage will sag down to 10 volts or lower. If the battery stays above 11.8 volts it will generally still start the vehicle.

## Is 12.2 volts enough to start a car?

12.2v is enough to start the car. It’s a 12v battery after all, it’s just voltage settling after being at ~14v when driving.

## Is 12.4 volts enough to start a car?

Car Battery Voltage A fully charged battery should read 12.6 volts or above. When the engine is running, that number should be between 13.7 and 14.7 volts. If the battery is reading at 12.4 volts, then it’s 75% charged.

## How much voltage should a car battery lose overnight?

Thanks for the question. The battery should maintain between 10 and 12.5 volts after a night of not being used. It should have about 10 volts to start the vehicle. Less than that it’s likely the engine will not start.

## How much battery power does it take to start a car?

“Starting the engine draws 100 to 130 amps, and idling the car for 15 minutes might put back three or four amps,” Brown-Harrison says. “If you’re idling only for 15 to 20 minutes, the battery never truly gets recharged.