Are Cheap Car Batteries Worth It? Avoid these common mistakes


The car battery is the initial heartbeat of modern-day cars. Without it, your car would simply not start. Unfortunately, it’s a part of your car that needs replacement every so often. As with most things, we want to spend the least amount of money as we have to. But are cheap car batteries worth it?

Cheap batteries are not worth it, however, very expressive batteries are not worth it either. There are diminishing returns the higher up in price you go. While the upper price bracket may be better stats-wise, sometimes it’s not apparent in the real world. However, those who live in colder climates might want to err on the side of caution and look for the most robust battery they can afford.

As long as you are not going too cheap, you should be fine with a lot of the value options sold by major retailers. Below we will go over all the information you need to know to see if your cheap car battery choice is the right one. I’ll also cover the two most common mistakes made when swapping out a car battery.

What Does a Car Battery Do?

A car battery is sometimes referred to as an “SLI Battery”. SLI is an acronym for its responsibilities, starting, lighting, and ignition. In case of an electrical problem, your car battery is also capable of powering your car’s electronics, but it is not its intended purpose.

Car batteries typically only use about 3% of their battery capacity to start the car, before having the car’s alternator charge them back up. These types of batteries are not good for having deep discharges as they can decrease their lifespan. This is why your battery is reliant on your engine to keep it consistently charged.

Types of batteries

Outside of niche cases, you will essentially see two types of car batteries. These two are the “traditional” Flooded Lead Acid batteries and the more expensive, less common, Absorbent Glass Mat (AGM) batteries.

Flooded Lead Acid (FLA)

These are by far the most commonly found batteries within cars. The basic construction of these batteries includes lead plates, water and sulfuric acid electrolyte, and plate separators. As the reaction occurs, the electrolyte is converted into hydrogen and oxygen that needs to be vented out.

Due to this venting process, these batteries sometimes need to be topped up with distilled water as the electrolyte level gets lower. Additionally, due to the gas escape, these batteries are not good options for cars that place their batteries in places other than the engine bay.

Any cheap car battery you encounter will most likely be an FLA battery.

Absorbent Glass Mat (AGM)

The actual chemistry of an AGM battery is the same as the FLA battery. However, the construction is different. As the name implies, the battery plates are wrapped in a fiberglass mat. This allows the electrolyte and its byproducts to be absorbed and recombine, eliminating the need for constant venting. There is however still a vent in place in the off chance that the AGM battery is overcharged and needs to release pressure.

Due to the “dry” nature of the battery, it doesn’t need to be opened up to add more electrolytes and is typically advertised as “maintenance-free”. Other benefits include being able to mount the battery in any orientation since there is no liquid to leak out (FLA batteries need to be upright). AGM batteries are also said to be more durable due to their tighter packaging. Lastly, these batteries should be more tolerant of deep discharges without shortening the overall lifespan.

All of these benefits come at a cost, however, and so AGM batteries will always come at a steeper price.

Important Car Battery Specs

When looking at a new car battery there are a few specifications that you should be familiar with. These two numbers will allow you to better understand and compare different car batteries. Typically the higher up in price you go, the higher the following numbers will be.

Cold Cranking Amps (CCA)

CCA also known as Cold Cranking Amps, defines how well your battery can perform in cold weather. The metric displays the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts per cell. Obviously, the higher the number, the larger the starting power.

There is also a Cranking Amps metric which measures the same thing but in a warmer temperature. Given that it is harder to transfer power in colder climates, the CCA is viewed as more important, even if you don’t live in frigid climates.

As a car battery ages, the amount of power that it can output will also decrease, eventually getting to a point where it won’t be enough to start the car. As such it is recommended that you get a battery with a CCA that meets or exceeds your manufacturer’s recommendations.

Reserve Capacity (RC)

If CCA tells you how much power your battery can output in a quick spurt, RC tells you how long your battery can output a sustained amount of power.

Reserve Capacity measures how long a fully-charged battery can deliver 25 amps of current in an 80°F-environment before the battery is discharged down to 10.5 volts.

This metric will allow you to know how long your battery will last if it has to power your entire car due to electrical issues.

Production Date

While it’s not exactly a specification, it should be a number that you note when looking at a battery.

Simply put, you don’t want a battery that has been sitting around for months. Make sure to find the date code on the exterior so that you know you are getting a relatively fresh battery.

Car Battery Warranty

Looking at the warranty period offered on a particular battery is another way that you can gauge the quality of your battery. If your cheap car battery comes with a 90-day warranty or less, then perhaps it’s too cheap. If a manufacturer is confident in the quality of their product, then they’ll have little issue granting a longer warranty.

Looking at retailers like Advanced Auto Parts and Autozone, we can see that there is clearly a difference in perceived quality based on warranty periods. Of course, you shouldn’t base your purchase decision based solely on the warranty period, but it should be taken into consideration.

How Long Does a Car Battery Last?

Conditions and proper maintenance (if needed) will greatly affect the total lifespan of your battery. Constant deep discharges of your battery will greatly decrease the lifespan as well.

Most car batteries will last about three years and can go up to five years but rarely beyond. Most of the batteries making it to five years or more will be the more robust AGM batteries, so they could be worth the money in the long run.

Avoid Two Battery Replacing Mistakes

Batteries as you know do fail every few years. However, battery failure is less common in late model cars. And that’s because late model cars employ a battery control module. Its function is to monitor the battery condition, vitals such as battery load, temperature, and state of charge.

Battery health is vitally important to late model cars, and that’s because of the sophisticated electronic technology they use.

Sophisticated technology won’t tolerate low voltage or voltage spikes. Battery health is therefore mission-critical to how modern cars function.

That brings me to the two most common mistakes made when replacing car batteries.

Number one – Not using a KAM (Keep Alive Memory) tool

Number two – Not coding the new battery to the battery control module

I cover both these topics together with a beginner’s guide to changing the car battery here “How hard to change car battery?.”

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John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of classic car ownership, from tires to roof aerials and everything in between.

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