Guide to Choosing a Replacement Car Battery

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Five Important Factors in Choosing a Car Battery

  1. Size
  2. Brand
  3. Reserve Capacity
  4. Age
  5. Cold-Cranking Amps


The car battery is located under the hood of your vehicle. In addition to providing the electricity for your door locks, sliding windows, lights, and other car accessories, it also allows you to start your vehicle. When your battery dies, your car stops working.

Batteries, just like other motor-vehicle components, wear out over time and need to be replaced. DIY car battery replacement can save you a lot of money, but how do you make sure you’re selecting the right battery? When searching for the right replacement battery, five important factors must be considered.

1. Car's Battery Group Size

Common Car Battery Group Sizes

  • Size 75: Most General Motors cars
  • Size 65: Large-bodied Ford, Lincoln, and Mercury cars
  • Size 35: Recent Honda, Nissan, and Toyota cars
  • Size 34: Most Chrysler cars
  • Size 34/78: Some Chrysler and General Motors cars

Make sure your car battery fits snugly and securely in its battery tray. The size of a car’s battery tray varies depending on the manufacturer, but most are designed to hold batteries of a specific group size.

A car’s battery group size can be found in the owner’s manual under the battery section. To determine the appropriate battery group size for your car, consult the reference guides provided by battery retailers if you no longer have access to your original owner’s manual.

2. Battery Brand

Ideally, you should buy the battery brand specified in your vehicle owner’s manual. If you find that the recommended brand is too expensive and you want to do some cost-cutting, make sure to choose only batteries whose specifications meet the specifications outlined in your owner’s manual.

Buying the cheapest brand is not always the best option. Batteries that are cheap are frequently defective and perform poorly over time. Cheap batteries may save you money in the short term, but maintenance and replacement will likely cost you more in the long run.

3. Car Battery Age

Batteries tend to perform better and last longer when they are new. Check the manufacturing date of any replacement battery you are considering for your vehicle. Generally, a car battery is considered “fresh” if it is less than six months old.

Manufacturing dates are rarely listed in conventional notation. The age of a car battery is instead indicated by 2-character alphanumeric codes. The first character of the code will be a letter from A to L, representing the month of manufacture; the second character will be a number from 0 to 9, representing the year of manufacture.

4. Car Battery's Reserve Capacity

A battery’s reserve capacity rating (RC) refers to its “standing power.” This is the amount of time it can continuously supply the minimum voltage needed to run the car if the alternator or fan belt failed. Your car will be able to run on its battery alone if the alternator stops working.

You shouldn’t simply choose the battery with the longest reserve capacity you can find. Consult your owner’s manual to determine the recommended reserve capacity rating for your car. Choose batteries whose RC rating falls within the recommended range listed in your vehicle’s owner’s manual.

Battery RC ratings are usually listed in minutes.

5. Car Battery's Cold-Cranking Amp Rating

Cold-cranking amps (CCA) measure your battery’s ability to start your car in extremely cold weather. Many vehicles are difficult to start (ignite) during freezing conditions because of thickened engine oil.

A battery’s cold cranking amp rating is the maximum current it can supply for 30 seconds at 0 degrees Fahrenheit. Choosing a battery with a high CCA you should choose a battery with a high CCA rating.