How Many Volts Is A Car Battery?

There is a lot that goes into picking the right battery for your vehicle. First off, you need to know what size you need, as there are several types of batteries out there, such as 24F or H6. You then need to determine your typical usage and environment. For instance, some car batteries can withstand cold weather better than others, while others have a longer battery life. While there is a lot that goes into choosing the right battery for your car, they will have one thing in common: they are all probably 12-volt batteries.

This has been the common voltage for car batteries going all the way back to the mid-1950s, when cars transitioned away from 6-volt batteries. Even modern electric vehicles use 12-volt batteries under their hoods. This is an ideal voltage for generating enough power to start a vehicle, which is the battery's primary function.

While everyone refers to it as a 12-volt battery, it is not technically a 12-volt battery. In reality, its resting voltage is 12.6 volts. Once you turn the car on, though, the alternator kicks in and can increase it to 13 or 14 volts. This is how things like your car's lights and infotainment system are powered and how your battery can stay charged without an external charger. Of course, these numbers are when the battery is operating at maximum power, but that won't always happen.

A car battery may generate 12.6 volts when you first get it, but it's not going to stay that way. Just like any battery, its maximum output will decrease over time. There will be obvious signs that your battery isn't making enough power anymore, ranging from dim headlights to certain electronic features not operating. Then, of course, there will be times when your battery struggles to start — or simply won't start — your vehicle, with the latter requiring a jump start. Nobody wants to be surprised by these, though, so there are ways to test your car's battery to know when it needs charging or replacing.

You can either test the battery's voltage yourself with a multimeter or voltmeter at home or bring the battery to a mechanic and have a professional do it. Getting your battery's voltage checked every six months — about as often as an oil change — is a good idea, though you can do it more frequently if you're checking at home.

If your multimeter reads 12.6 volts or higher, your battery's fully charged. If it's between 12.2 and 12.5 volts, it could use a charge to bring it back up to 12.6. If it's at or below 12 volts, then it may also just need a charge, especially if it only happens once. However, if you notice the battery regularly dropping to 12 volts or lower, that means it can't hold a charge anymore. In that case, it is probably time to buy yourself a replacement car battery.