12-volt Battery Voltage at Rest – Cycle Life and Calculation

Batteries inside the cars help a lot not only for starting the engines easily but there are several other benefits. While you are enjoying all the benefits of your car battery you must understand that you need to take care of your car’s battery for it to last for the longest time possible per charge and per life as well.

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However, the issue is that most people do not even know the basics about their 12-volt car batteries. So, here we will be discussing all that you need to know about 12 volt car batteries life and calculation.

What is the voltage reading of 12 volt battery in case of dead battery?

The first thing that you need to know about your battery is if it is dead or if it only needs a recharge. These are two very different cases wherein one case the battery is only discharged, and it is called dead, flat or down are also among some common terms used in this case.

In the other case, the battery has completed its lifetime and now there is no way it will be performing like usual. In this case, it is also called dead.

Dead in Terms of Charging

Consider that you have a 12-volt car battery, and it is not performing as it should perform. Now there are two ways to check the battery and the easier one is to check the voltage first. So, when you check the voltage of that battery it comes out to be 12.0 volts or even lower.

In that case, it means that the battery is at 0% charging, or it is completely discharged. All you need to do in this case is to plug the battery into a charger and it will be good to go again.

Dead in Terms of Life

Sometimes the battery is not able to hold a charge for any period and the voltage is nearly 10 volts, 10.5 volts, or even lower. In this case, you can also verify the condition of your battery with a gravity meter. However, there is not a lot left to be done. You either get your battery rejuvenated or replaced.

What voltage should a good 12 volt battery read?

Now that you know about the voltage readings of a dead battery. It is also a good choice to learn about the voltage readings of a good battery. The important thing to consider is that a good battery can also sometimes show unsafe voltages. So, here we will be explaining all categories of voltages that you can get from a 12-volt battery in good condition.

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Complete Charging

When your 12-volt battery is holding full charge or 100% charging then it must give off a voltage reading of 12.6 volts. It can go a little above but if it goes down then it means that either the battery is not 100% charged or there is some issue with the battery.

Other Safe Charging Ranges

When you are checking the voltage of a good 12 volt battery there are major changes of it being randomly charged. So, you can get voltages between 12.0 volts to 12.8 volts. It will tell that the battery is in good condition and holding a specific amount of charge.

Unsafe Charging Ranges

The battery might be in a good condition, but it can still show some unsafe charging ranges. These are in the case where things start to get worse and if not changed will damage the battery as well as the whole system.

The voltage range that you may get here could be above 12.9 volts. A voltage this high is usually because of a faulty alternator inside a car that is overcharging the car battery.

By knowing all of these safe and unsafe battery voltage ranges you can easily know the live stats of your car’s battery.

What is the resting voltage of a 12 volt car battery?

Before jumping right onto the voltage, it is important to know what a resting car battery is. So, the resting car battery is when the engine is not running, and no other accessories or electronics of the car are turned on. In this way, the battery shows the real voltage that it can hold.

Let’s assume that everything is working perfectly fine in your car.

The alternator is charging your car battery perfectly then the resting voltage that you will find will fall somewhere between 12.0 volts and 12.8 volts. It depends on how much charging the battery is holding and if the battery is 100% charged then it will show the voltage between 12.6 volts and 12.8 volts.

The voltage readings below this range up to 12.0 volts are also safe but it means that the battery is not completely charged, and it needs charging.

What if the resting voltage of your car battery is different?

Sometimes you get the resting voltage of your car battery that is different from the range mentioned above. There can be two different scenarios in this case regarding different voltages of 12 volt battery. One is that the battery is not getting enough charging and it is being undercharged. In this case, the voltage can be between 10.5 volts to 12.0 volts.

The other case is about the battery getting overcharged and in this case the voltage will be about 12.9 volts or above it. You can find these voltage readings in your resting car battery and in any of these cases it is best to make a professional look at the matter before anything bad happens.

Conclusion

Knowing only about the voltage reading about your 12 volt battery can save you from a lot of issues. If you keep testing or keep track of the voltage of your battery regularly then you can also know about its health and overall condition.

Now we hope that you know all about the different battery voltage readings that you will get from your 12 batteries under different circumstances. So, now you can take good care of your car’s battery.