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What Size Battery For My Car? [ Here’s A Guide With Checklist ]

What Size Battery For My Car? [ Here’s A Guide With Checklist ]

No matter how high-end or tech-savvy your beast is, it will become non-functional as soon as its heart, i.e., the battery, will die out.

Located just under the car’s hood (in some models, you may also find it somewhere else), it’s the essential component of your car. Why it’s so is because of the various roles it plays.

For example, a battery is responsible for starting your car. Following this, the power windows you use, the radio/infotainment system you enjoy, the air conditioner you turn on, and every other thing functions due to that single battery.

Even the headlights, taillights, and other lighting elements run on the battery. All this proves why a car battery is of utmost importance.

Like the other car components, the battery has a defined age till which it will go fine and start to surrender gradually post completing its term.

The legal age is 3-5 years for most batteries, and you will get various indications to change it post this. If your car battery is on the verge of surrendering, you will need to invest in a brand new piece.

Of all the factors you will consider for the same, the battery’s size is quite confusing. So, let’s discuss the battery size and its importance in detail today.

How do I know what size battery to buy for my car?

Is your car battery finally on the verge of bidding farewell to your car? If yes, it’s the right time to invest in a new battery, and while choosing the new one, you will have to consider many factors.

However, above all, its size is something you’ll need to think twice (or thrice?).

So, let’s clear your doubts, and here are some excellent ways to determine what size of a car battery is the most suitable for you.


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Measure the dimensions of the current battery

Though choosing a battery size involves a complicated process (I’ll come to this later), you can still know which battery size to buy by simply measuring the dimensions of your current old battery. For this, take out the battery from the car.

Next, take any measuring tape and measure the length, height, and width of the battery. Now, you can go to any battery store and convey the above dimensions to them, and they will get you the battery of the exact size.

Check the group size engraved on the old battery

The manufacturers engrave their group size on every battery as per the BCI (Battery Council International). If your battery is old enough to use the above method, the group size won’t be visible.

However, if the battery group size is visible, note down the battery group. Usually, this information is available on the top or side of the battery case on most batteries.

These battery group sizes are generally in the form of a two-digit number followed by a digit. For example, the standard battery group sizes are: 24, 24F, 25, 34, 35, 51, 51R, 52, 58, 58R, 59, and 65.

Check the owner’s manual

Your owner’s manual is another quick way to get information about your car and its battery’s group size. Pick your manual, head to the battery specs section, and there you will get all the required information about the battery and its group size too.

Head to any nearby battery shop

There are chances that you may not be sure about the measurements done manually, the group size isn’t visible on the battery, or you have misplaced your owner’s manual.

It means failure of the above three ways. If yes, your next resort is to visit any nearby battery store from where you intend to purchase the new battery for your car.

Using their experience, they will quickly figure out the exact battery size for your car.

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Use any online battery size finder tool

Yes, technology finds a way or two to simplify your tasks. Today, you can also use any online application that helps in finding the battery group size.

After opening the tool, every tool will ask you for essential yet vital information like your car’s year, make, model, and engine size.

Upon entering these details, you will get the complete details of your car’s most accurate battery size.

So, these are the top and common ways to find your car’s battery size. Let’s now understand it is possible to put a different size battery in your car or not.

Can you put a different size battery in your car?

First and foremost, when we are talking about the battery size, it’s equally important to remember that the battery size determines how much power it can let out to the car.

For the time being, memorize that the smaller the battery size, the fewer accessories your car will support, and vice-versa.

Every car battery manufactured in the various corners of the world follows the guidelines of the BCI (Battery Council International) that lays down the various other aspects of a battery.

For the battery size, it provides every battery with a group size. In simple terms, this battery group size is an industry-standard for the batteries to describe their height, width, and length.

Through this group size, you can easily find a new battery of the exact size irrespective of the brand and other factors.

However, don’t think of using a wrong or different battery size in your car if yours isn’t available, or you can save many bucks by doing so!

Every car, be it small or big, requires a predefined battery for its various components to work correctly. For example, consider General Motor cars and European vehicle manufacturers like Audi.

While General Motor vehicles use battery sizes like 70, 74, 75, and 78, Audi usually uses battery groups size H5, H6, etc.

In a nutshell, you can not use any different battery size with your car. Even if you tend to use it, the following section will prevent you from doing so!


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What happens if you put the wrong size battery in your car?

As I said above, using the correct battery size is crucial for the smooth running of your car.

However, some owners end up fixing either an undersized battery or an oversized battery in their car. If you are thinking about the same, you will face all possible issues in both scenarios.

If you have used an undersized battery in your car:

With an undersized car battery, you are more likely to experience the following range of issues.

  • Loss of power or lack of power is the main issue you will encounter. The size of the battery determines how much current it will pass to the various car components. That is why you may find it challenging to run the AC or play the radio in such a scenario. Further, your car’s other accessories may not function due to insufficient energy supply from the undersized battery.
  • The smaller the battery against your car’s needs, the more its life span will reduce. Let’s understand this. You must know that shorter trips shorten the battery life. For example, first, you traveled to the nearby grocery store. Then, you took a short trip to the nearby school. Now, if you have to again travel to the grocery store, your battery may not support you this time. This time, it will require a significant energy boost to operate, which isn’t possible due to its undersize and car’s big build.
  • Smaller batteries have insufficient cranking power. Decent cranking power is a must for weather conditions where the temperature suddenly drops or surges, making it difficult for the battery to crank up the engine.
  • In most cars, you get a small alternator to merely support the battery for starting the car and running from thereon. However, if the battery is too small, it will suck out more power from the alternator. If you repeat this regularly, the alternator will wear out soon. The situation will worsen further if you have added several other power-sucking accessories to your car.
  • Last but not least, smaller batteries will make the fuse blow.

So, these are the significant consequences of using an undersized battery in your car.

If you have used an oversized battery in your car:

If you have an oversized battery in your car, it’s against the basic principles, and here are its consequences.

By using an oversized battery, first of all, it won’t fit in the battery tray. Due to this, it will keep moving here and there.

Also, if the battery is not sitting firmly in its place, its terminals may contact other metal parts of the car and cause sparks or a severe accident.

Another big issue with using a big battery is that the car’s alternator will have to continuously work hard to supply enough charge to keep the battery running, even if it goes above the alternator’s capacity. It will again lead to a quick wearing of your alternator.

Lastly, a large battery may put excessive weight on your car’s overall weight if you own a small to medium-sized car. Hence, these are the safety issues and other problems associated with using the wrong battery in your car.


A standard car battery can last for as long as 3-5 years, no matter how well you look after it.

After passing its term, it will start displaying signs of wearing down like lack of power, difficulty starting the car, inability to keep the charge, etc. Hence, you’ll have to get a new battery unit for your car.

Choosing an ideal battery, especially in terms of size, is challenging for some owners. For example, how to figure out the exact battery size.

For this purpose, I have discussed the top ways and why you can’t go wrong with the battery size. It is because undersized and oversized car batteries can lead to whole new issues in your car, as discussed above.

Hence, ensure your new car battery is precise as per your car’s BCI standard.

BCI stands for Battery Council International, and it’s responsible for the various aspects of automobile batteries, including their size.