7 Factors to Consider Before Buying a Car Battery

You know replacing car batteries is a critical part of your vehicle’s maintenance, but do you know what to look for in buying a car battery? There are many factors to consider, and your choice of battery could affect your vehicle’s performance for years to come.

Read on to learn what types of car batteries there are, the most important car battery features to consider, and which battery we recommend to meet your high-performance needs.

What Types of Car Batteries Are There?

Are all car batteries the same? If you’re not used to changing your own car battery, you might be surprised to learn that there are a lot of varieties to choose from! Fundamentally, most batteries work the same way: by turning chemical energy into electrical current. But the main differences in battery types and sizes come from how they’re constructed.

Car batteries come in two basic varieties: the more traditional maintenance-free and the more advanced absorbed glass mat (AGM).

Lead-Acid (Regular)

Batteries once required drivers to periodically top off the water in the electrolyte solution, the liquid inside that is the battery’s power source. Modern maintenance-free batteries consume far less water than traditional “flooded cell” ones.

Low-maintenance batteries retain their fluid for the life of the battery, and the caps on these models aren’t meant to be removed. There are still some batteries than can be topped off with distilled water; properly maintained, these may last longer in hot climates.

A lead-acid battery will generally cost significantly less than an absorbed glass mat battery. However, it will not hold a charge for as long and is less able to tolerate a deep discharge.

Absorbed Glass Mat (AGM)

AGMs are built to better stand up to repeated draining and recharging cycles than standard batteries. They are becoming standard equipment in more cars because modern features such as fuel-saving stop-start systems, electronic safety, and convenience features, and power outlets for mobile electronics all increase the demand for power.

But AGMs can cost 40 to 100 percent more than highly rated conventional batteries. Consider buying one if you sometimes don’t use your vehicle for long periods and the battery loses its charge. An AGM battery can better tolerate a deep discharge, and it is more likely to fully recover if it is accidentally drained.

Other Car Battery Types

While the above battery types cover what most people will have to choose from, there are a few other types of car batteries worth mentioning, such as:

  • Deep Cycle Battery: Deep cycle batteries also called marine batteries are best for delivering sustained, low current power over extended periods of time. They get their name from their ability to repeatedly recover from cycles of deep discharging and recharging without suffering damage as conventional batteries would. Deep cycle batteries are not suited for cars, trucks, or SUVs, but rather vehicles like RVs, boats, and golf carts that need to power electronics without an engine running.
  • Lithium-Ion Battery: Lithium-ion batteries are the standard batteries for most modern hybrid and electric vehicle high voltage battery packs. Lithium-ion batteries store more energy, charge faster, are lighter, and last longer than their conventional counterparts. Some newer vehicles come equipped with a 12-volt lithium-ion battery from the factory.

What To Look for In A Car Battery?

When searching for a new car battery, there isn’t a singular “best” car battery to buy. Instead, it’s a question of which battery is best for your vehicle’s specific make and model?

Most car batteries are limited to a lifespan of 3-5 years depending on the nature of the trips and climatic conditions. Here are a few tips on what to look out for when buying a new battery for your car.


1. Check Your Owner’s Manual

Buying a car battery, yourself rather than through a dealership or mechanic can save you some money. But it’ll be a complete waste if you buy the wrong battery for your vehicle.

That’s why you’re going to need to pull out that handy owner’s manual that came with your car. The manual should tell you the size of the battery your car requires. If you don’t purchase the right battery size it won’t be able to properly fit in the battery tray which could cause vibration that might damage the battery.

The owner’s manual will also provide you with the type of battery needed for your car. This will help you choose one that has terminal locations in the right place. If you can’t find your owner’s manual you can also look up your vehicle on the in-store fit guide.

2. Battery Freshness

Battery freshness is indicated by a code on the battery which consists of a letter and number. The letter stands for the month whereas the number stands for the year of manufacture e.g. B/4 stands for February 2014. You should never buy a battery that is older than six months from the date of manufacture.

3. Reserve Capacity

On top of making sure your battery will fit correctly into your car, it’s also important to note the performance of the brand and model.

Look into the top-performing batteries for the year. This can vary from year to year and size to size so be sure you find a brand and model that has gotten a good rating.

You can also purchase a battery that has a good reserve capacity. This is the amount of time that a battery can run on its own without the power of the car. Having a high reserve capacity can help prevent your car from going dead if you forget to turn the lights off.

4. Power Requirement

This refers to Cold Cranking Amps (CCA) and Cranking Amps (CA). Cranking Amps is the energy required to start a vehicle at temperatures of 32 degrees Fahrenheit while Cold Cranking Amp points to the ability of the battery to start a car at 0 degrees Fahrenheit. CCA applies to cold climates and batteries with higher CCA are recommended.

5. Maintenance

Car batteries can come in two types. There are low-maintenance and maintenance-free batteries. Maintenance-free batteries are sealed and don’t need the liquid electrolyte to be replaced throughout the battery’s life. 

The low-maintenance batteries require you to add distilled water occasionally and have unsealed caps. Batteries that require maintenance need to be serviced every six months. They could stop working without regular maintenance, which means you would have to buy a new battery.

If you want to avoid the added stress, then keep it simple and purchase a battery that is maintenance-free. 

6. Warranties

Another factor when purchasing a new car battery is a warranty. Choose a battery that has a longer warranty and allows for the battery to be replaced for free. There will most likely be a free replacement period combined with the prorated period.

This lets you receive a partial reimbursement of the total cost for a certain time period.

7. Type and Position of Terminals

The position of the positive terminal affects the polarity of the car and there is a risk of shorting if the positive terminal contacts the metal shell of the car. It is therefore very crucial to check what side the positive terminal is located whether right or left depending on the type of car.

8. Ampere Hour (Ah)

This refers to how much electricity the battery can store (capacity). A higher Ah means that the battery can maintain a load for a long time thus chances of the battery running out are less.

9. Battery Life

You can check the battery life of your current battery at an auto parts store or battery specialist. This will help you know if you need a new battery or just a maintenance procedure.

10. Previous Experience

Before buying a battery, consider your own previous experience with the battery type. A battery that served you for a long time without issues is preferable, and you can always compare this experience with friends.

How We Test

CR evaluates car batteries in three ways:

1. Cold-cranking amps

Cold-cranking amps (CCA) is a measure of how well the battery starts an engine during extremely cold weather. We use a freezer to simulate winter conditions, cool batteries to 0° F, and rate batteries based on their performance.

We feel that our CCA test is based on more realistic charging voltages and amperage demands than typical manufacturers’ tests, and our results show each battery’s relative cranking power, regardless of the manufacturer’s claims.

2. Reserve capacity

Reserve capacity indicates how long a battery can run a vehicle if the charging system—the alternator, stator, and rotor—fails. It’s also a measure of how long you can accidentally leave the headlights on and still get the car started without needing a jump-start.

To test reserve capacity, our engineers measure how long it takes a fully charged battery to be discharged down to 10.5 volts, which is considered to be fully discharged. At that level, the car will be unable to start without a jump-start.

We consider 1½ hours of power to be average. Higher-scoring models can supply power well past 2 hours.

3. Battery life

Battery life is measured by repeatedly discharging and recharging each battery about 3,000 times at a test temperature of about 167° F for 15 weeks or until performance drops to unacceptable levels.

This simulates the hot underhood conditions a battery can face during the summer, the hardest time of year for batteries because of the heat. Frequent high temperatures are very tough on batteries, increasing plate corrosion and more quickly vaporizing the electrolyte needed for current.

Long life is especially important if you make many short trips that don’t allow much time for recharging. The higher the score, the longer the battery will be reliable.