What Is The Voltage Of A Dead 12 Volt Battery?

Key points:

  • A dead 12 volt battery will be charged at 12.0 volts directly.
  • Dead or low charged batteries are needed to charge immediately
  • Multiple ways are available to determine if the battery is getting bad.

The battery is one of the most crucial parts, especially for a vehicle. As the battery has a lifetime, it will be dead sometimes. Do you know at what voltage a 12-volt battery is considered dead? How to tell if a battery goes bad?

Well, an easy way to determine if the battery went dead is to determine the state of charge. Flat dead batteries are typically charged at 12 volts, while the batteries that are charged fully show their charge level in between 12.7 to 13.2 volts.

If what is the voltage of a dead 12-volt battery is your question to ask, this article will certainly answer that. Also, it discusses how to determine if the battery goes bad.

So, let’s get started!

At What Voltage Is a 12 Volt Battery Considered Dead?

A 12 volt battery is widely used for several purposes including charging RV. To keep them functional, you have to charge them frequently. However, a battery doesn’t get charged in the same way and up to the same level in all states.

In fact, there is a chart available to determine the state of charge of a battery. It shows how a battery shows different voltages when charged in different states. Here’s a table of the chart:

Charge StateVoltage level
100%12.7 – 13.2
75%12.4
50%12.1
25%11.7
Discharged0 – 11.6
Dead/ Fully discharged12.0

If the battery gives a 0 voltage rating, it is either completely discharged or high chances are it is having an internal short circuit. The battery shows values higher than 12V when it has over 50% of the total charge. For example, it has 12.1 – 12.3 voltage when it is half charged. Again, if the battery is fully charged AKA 100% charged, it shows about 12.7 to 13.2 voltage while measuring.

However, if the 12-volt battery shows a 12.0 volts reading, it is either completely discharged or flat dead and should be recharged as soon as possible. At 12.0 or below, the battery needs to be charged immediately as its lifespan is seriously affected if it remains within this voltage range for a long period of time.

How to Tell If A Battery Is Bad or Good?

A healthy battery is all we need, isn’t it? Having chemicals inside, it is very much possible to get some trouble with a battery. However, if treated and maintained well, a battery should last long. That is why it is really important to identify if your battery is truly bad or getting there slowly.

Well, there are some ways to identify if the battery is draining fast to go bad. One of the ways was taking the voltage reading that was discussed above. When the battery shows 12.0 voltage or anything less than that, you should charge it immediately as it may otherwise affect battery health.

Another way of testing your battery is inspecting. If you look closely sometimes, you may understand if it is getting worse or not. There are a few crucial points to be inspected such as a broken terminal, bulge or crack in the case, discolouration, or excessive leaking.

These symptoms can be dangerous and can result in short circuits. So, it is recommended to have a good look at the battery sometimes.

You can also determine the faulty battery is to undergoing a load test of the battery. You may need to visit an automotive shop for that but if you have a digital voltmeter, you can do it at your home as well.

The battery has to be fully charged and left idle for 12 hours before starting the test. This is because it will release the residual charge from the battery to show more accurate results.

Consider that you’ll do the load test on a 12-volt battery of your bike. You have to hold the prongs of the voltmeter according to the terminals of the battery. Then, push the start button and see where the voltage drops to. A battery with decent health maintains a voltage range around 9.6V to 10.5V up to 30 seconds or more.

If you see any dropping of the voltage meter, you probably have a discharged battery. Again, if the starting voltage drops below the mark of 9.6V, the battery health should alarm you and sometimes you may have to replace it.

There are some effective ways to maximize your battery’s life. You may have to give a little more effort but it will surely be worth it.

Final Word

So, now you know what is the voltage of a dead 12-volt battery after reading through the article. It also discussed how to identify if the battery is running badly.

For a smooth operation, a healthy battery is the first requirement. Knowing the dead voltage of a 12-volt battery will help you to charge or replace it immediately before it is too late.

I hope this article helps you. If so, please share it with everyone, and in case of any queries, drop them in the comment box below. I’d be happy to respond.

Thanks a lot!

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