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Best Car Battery of 2021: Take Charge of Your Electrical Needs

Batteries are everywhere, including in your car. They help start the car up, power the radio, and make the AC run during the hot summer months when it is sweltering inside your vehicle. Needless to say, having a good one is important. 

Given that your battery is necessary for starting your vehicle, it important to make sure your battery is durable, has a good reputation, and is taken care of to make sure you can get back home or get to work when you need to. Some of the best batteries, when you take care of them, can last as long as five or six years

The Best Car Batteries

Even though batteries can last a long time, chances are that you will have to replace your vehicle’s stock battery at some point. When that time comes, it is important to understand what differentiates a good battery from a bad battery and to know what to look for in terms of size, desired results, and what your vehicle needs.

1. Delphi MaxStart AGM Premium Automotive Battery

The Delphi MaxStart AGM Premium is a 65 group size lead-acid battery that weighs less, costs less, and is built to last longer than other comparable batteries. Its absorbed glass mat technology delivers longer battery life and quicker charging times than other competitors and provides direct OEM replacement fitment.  

Delphi hangs this product on its ability to resist corrosion and vibration. It is built with fortified posts, straps, and welds, as well as component compression optimization techniques to provide 20% more vibration resistance compared to conventional batteries. 

It is rated at 750 cold-cranking amps and 150-minute reserve capacity to make sure that starting your vehicle and powering its electronics are always possible. It is also rated at 12 volts, a typical rating for most average vehicle batteries. 

2. Odyssey Performance Series 48-720 Battery

The Odyssey 48-720 battery is a highly-rated and relatively affordable AGM, 48 group size battery that is specifically designed to power your vehicle’s accessories. It is engineered with high deep-cycle capabilities that provide long-term charge over and over again.

It is also engineered to be as durable and long-lasting as higher-end batteries but without the added cold-cranking amps or reserve capacity that larger and more premium batteries require. Rated at 720 cold-cranking amps and a 130-minute reserve capacity, this battery delivers a lot of bang for the buck.

All of this is accomplished with Odyssey’s pure lead flat plate design. They are thinner than many other lead-alloy designs which means that they can pack more into a smaller area, increasing the surface area of the plates. The result is increased power and overall battery performance.

3. Optima Batteries D35 YellowTop Dual-Purpose Battery

Optima Batteries is a well-respected brand and the D35 YellowTop is a highly-rated battery. It does look a little different than many other conventional car batteries, but this group 35 battery is designed like this for the highest amount of personal safety, durability, and longevity possible. 

With high deep-cycle capabilities as well as superior cranking power, the YellowTop is designed to provide power to vehicles, trucks, and ATVs with multiple aftermarket accessories or with several extra dealer accessories. Additionally, its low self-discharge rate allows it to be used in vehicles that sit for a long time through the winter months or are not driven frequently.

Its unique design helps provide 15% more vibration resistance than other batteries while using 99% pure lead plates for added power. It is rated at 620 CCA and can handle a tremendous amount of charging and recharging. 

4. ACDelco M24AGM Professional AGM Voyager Battery

ACDelco is a long-time player in the battery industry. Though it comes at a fairly high price, the group 24 Professional AGM Voyager Battery proves its worth with a huge amount of technology packed into forty-four pounds of energy. This maintenance-free AGM battery provides great deep-cycle capability with plenty of cranking power.

Its lead-calcium alloy grids are designed to reduce potential corrosion while also producing very low self-discharge rates. When the battery is dead, its ability to be recharged multiple times will be beneficial to any buyer. The battery is leak and spillproof as a result of the electrolyte being held permanently within the glass mat separator.

Special valve regulation technology helps provide up to three times the amount of lifespan of a conventional battery, and an 18-month warranty provides even more peace of mind.

5. ACDelco 49AGM Professional AGM Automotive Battery

Another ACDelco product, this time in group 49. This AGM battery features silver-calcium cell composition for a longer lifespan. Also to aid in the extension of battery life is its improved acid circulation design, meant to keep the battery cooler.

These batteries are highly prized in vehicles with start/stop technology because of their high-cycling and recharging capabilities. Like the ACDelco Voyager battery, the ACDelco Professional is leak and spillproof as a result of its glass mat-contained electrolyte.

A 36-month warranty accompanies the purchase of an ACDelco Professional battery. It is rated at 900 cold crank amps and contains a 160-minute reserve capacity.

How Does a Car Battery Work?

agm battery

A car battery takes chemical energy and transforms it into electrical energy. In short, a battery cell contains a lead plate and lead oxide plate that triggers a reaction when submerged in sulfuric acid contained within the cell. Each cell can usually provide about two volts of charge, and there are usually three cells within a typical car battery for a total of twelve volts. 

Once this reaction begins, it causes electrons to be produced, in turn producing the energy your battery supplies to your vehicle. This reaction is reversible. When voltage is supplied to the battery, it causes lead dioxide to form on the plates, making the battery reusable and rechargeable.

Read More: Is it Possible to Overcharge a Car Battery?

Important Battery Terminology

Even the simplest batteries are quite complex in comparison to other vehicle parts. All the chemicals, components needed to harness those chemicals, safety features, and the terminology surrounding battery parameters are quite involved, but it is important to know some of the most basic and widely-used terms involving batteries to help further understand how they work.

Cold Cranking Power (CCA)

Cold-cranking power, or CCA, is one of the primary rating parameters for batteries. It is a basic measure of a battery’s ability to start a vehicle. More technically, it is the number of amps that can be taken away from a new battery at zero degrees Fahrenheit for thirty seconds and still have the battery able to hold 7.2 volts of energy. 

Reserve Capacity (RC)

Reserve capacity – RC – is another crucial battery parameter. It is the measure of a battery’s expected lifespan without the use of the alternator or generator recharging it. More technically, it is how long a battery can charge essential vehicle systems, delivering 25 amps at 80 degrees Fahrenheit at 1.75 volts per cell.

BCI Group Size

BCI stands for Battery Council International, and a battery’s group size is a set of physical parameters set by the BCI to describe a given battery. These parameters include physical size, terminal placement, and voltage, but do not necessarily define its capacity.

Discharge Cycle

Discharge cycle is another term for lifespan. It describes the battery’s usage over time until the battery can no longer provide enough power to perform normally.


An ampere, or amp for short, is the measure of current through a circuit. In the case of a battery, it is the electron flow rate. 


Voltage is the measure of electrical potential from an electrical source – the battery.


Deep-cycle is used to describe battery capabilities wherein it can be used steadily over a long time. Deep-cycle batteries or those with high deep-cycle capabilities are ideal when powering vehicles with various extra accessories.

Absorbed Glass Mat (AGM)

AGM batteries are batteries designed to both deliver powerful starting energy and power electronics for a long time. They are often thought about as dual-use since starting takes a powerful, quick burst of energy while powering electronics requires steady energy. These types of batteries do this by packing more led into each cell.


A battery terminal, or post, is what provides the external connection to a car battery. There is a negative and positive terminal, often visible when opening the hood of a car. These are what jumper cables hook to when a vehicle needs to be jump-started. They can be found on either the top or side of the battery.

Types of Car Batteries

marine battery

There are several different types of car batteries on the market. There is some crossover between types, but there are five commonly identified types of batteries.


Flooded batteries are one of the two main overall battery types. They are very simple and practical, providing your vehicle with standard starting and necessary component energy only. They are common in most average road vehicles and are used to save costs.


AGM batteries – Absorbed Glass Mat – are like beefed-up flooded batteries. As mentioned, they are more optimized to do a wider range of tasks and provide more power to more accessories than most standard batteries.


An SLI battery is more of a subtype of battery than anything else since both flooded and AGM batteries can also be SLI batteries. SLI stands for starting, lighting, and ignition. They provide the basic vehicle functions that require energy to run, as the name implies.


Lithium-ion batteries are not used so much as conventional “under-the-hood” batteries we think of, but they are more widely used in hybrid and electric vehicles. They are lighter, can be charged quicker, and hold a charge longer than typical batteries. Being more expensive as well, they are almost like the LED headlights of the battery world.


Lead-Acid batteries are beneficial for their low maintenance needs. They are sealed and have to be replaced rather than recharged, but their high energy output at a low cost makes them a fairly popular choice among consumers.

Things to Remember About Car Batteries

It is important to buy the proper battery for your vehicle. Your owner’s manual should have the proper battery type outlined within its pages. Additionally, many online sellers and automotive retailers have vehicle selectors that match battery fitment to your vehicle to assist buyers. This is both important for physical fitment and safety reasons.

And, speaking of safety, batteries can be dangerous since they are made with caustic and dangerous chemicals. Their maintenance and proper handling must be attended to, and all safety warnings must be headed to keep you out of harm’s way. Proper disposal is also extremely important because of a battery’s chemical makeup.

Final Thoughts

Car batteries are a vital part of any vehicle. Not only do they power electronics like the lights and radio, but they also help start your vehicle. Having a good, reliable battery suited to your needs and your vehicle’s needs is necessary for ensuring your safety and your drive home. 

Since batteries are made with many different complex components and hazardous chemicals, it is important to understand which battery type your vehicle needs, and it is equally important to take care of that battery and head all safety warnings that accompany it. 

Richard Reed
I've been a General Manager of a moving company and I've also been a Professional Mover for over 30 years. I've driven flat beds, reefers, dropdecks, moving vans, heavy machinery, etc. In my time as a Mover I've driven over 1,000,000 safe miles. My days of moving and driving truck are past me but The Vehicle Lab allows me to share the knowledge I've gained over the past 40 years.
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