What Should a 12 Volt Battery Read When Fully Charged

Most people already know that charging a 12-volt battery should be proportional to the charger’s voltage so that it can’t damage the device. However, some don’t know how to read and check a 12-volt battery, leaving them to say that it’s not advisable to fully charge the battery, while others say it’s okay to top it off. If you’re looking for answers about it, continue reading this blog.

What should a 12-volt battery read when fully charged?

You might have thought, what should a fully charged 12v battery read? When a 12-volt battery is fully charged, it should read between 12.60 and 14.25 volts. If your battery reads higher than this, it indicates that you’re overcharging your battery. Meanwhile, if your battery reads lower than this, it means that your battery is not fully charged.

If your battery’s voltage reads between 12.60 and 14.25 volts when you have a fully charged car battery, turn off the switch in your charger and disconnect it from the battery’s terminals. Once disconnected, clean the terminals and dry them. Put the battery back in its original location and replace its covers or panels.

What voltage is too low for a 12-volt battery?

A 12-volt battery is too low when the voltage falls below 12 volts. It means that it no longer provides enough power to the car‘s electrical system due to cold weather or dormant use of your vehicle. This results in the engine not starting, dashboard lights flickering on and off, or strange noises in the engine. It indicates that the battery needs to be checked or replaced in most cases. 

How to check a 12-volt battery?

You can use a voltmeter, also called a multimeter, to check the voltage of your battery. You can buy this for around $30-$50. Here are the steps you can follow to check it using a voltmeter:

1. Turn off the engine and remove all electrical loads from the vehicle, including headlights, radio, etc. If possible, disconnect any lights connected to the battery, such as a trailer light.

2. Locate the positive and negative terminals on the battery. The positive terminal is larger in diameter than the negative terminal and has a (+) sign next to it.

3. Attach one of the multimeter’s leads (usually red) to the positive battery terminal, and attach the other lead (usually black) to the negative terminal.

4. Turn on your multimeter by pressing or turning the knob. If you see a “DC” label next to one of those buttons, press it so you can measure DC voltages instead of AC voltages.

5. Look at the multimeter’s display to see what voltage it reads. This should be between 12 and 14 volts, which means your battery is working fine. If it reads less than 12 volts or more than 16 volts, you may need to replace the battery.

How do I know when my battery is fully charged?

Generally, most batteries are fully charged when they reach 12.6 volts. Nonetheless, it’s always best to check your car’s manual since knowing the indicators when your battery is fully charged varies depending on its model and brand.

How can I tell if my 12-volt battery is healthy?

You can check your 12-volt battery to see if it’s healthy by knowing its voltage using a voltmeter. A healthy battery should read 12 volts or more (as discussed above).

You can also check its electrolyte level by removing the caps on the top of the battery. Then, look at the color of the fluid inside. The liquid should be clear or light yellow. If it’s dark or cloudy, there is sediment floating in the electrolyte, and it’s time for a new battery.

Lastly, using a hydrometer to measure specific gravity, you can check out how much charge is left. A healthy battery has a specific gravity of 1.265 or higher. If it’s lower than that, it needs to be replaced. If you’re unsure about doing it, take your car to a mechanic and have them test the battery for you. A mechanic charges $50-$75 to test a battery.


It’s essential to keep your car battery healthy and charged. Not only does it ensure your car starts, but it also helps to extend your battery life. Knowing your battery’s health status guarantees fewer trips to the mechanic and a smoother ride for you and your passengers. Thus, regularly charge your batteries using the correct voltage and maintain your car battery in good condition by removing its corrosion.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.