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Despite all the noise about electric cars and their high-tech, high-voltage batteries, conventional 12-volt batteries remain the biggest chunk of the $100-billion auto battery market. That’s partly because every vehicle needs one, even those newfangled electric vehicles, which use dependable 12-volt systems to power lights, ventilation fans, radios (or Apple CarPlay) and so on. Familiar 12-volt auto batteries will remain important for a long time.
Whether your car is powered by electricity or gasoline, there’s no single component more vital to its consistent reliability than the battery. If you’ve noticed that car batteries don’t seem to last as long as they once did, your observation may not be far off the mark. The increasing number of electrically powered systems in the typical automobile – from heated and cooled seats to start/stop auto shutoff systems – puts an increasing strain on the battery, particularly in extreme climates.
There are more 12-volt battery technologies than ever before: traditional batteries with flooded lead acid, gel, absorbed glass mat, lithium ino batteries and more. Shopping for a car battery can be complicated, but the day your car won’t start isn’t the best time for a car owner to begin that process.
We’ve done the heavy lifting by assembling a list of some of the best car batteries available today over a broad price range, for everything from small-engine sedans to track cars to RVs. We’ve based our recommendations on the work of testing labs like Consumer Reports, expert interviews, user ratings at popular shopping sites and personal experience. Some you can purchase from an auto parts store, while others you can simply order from Amazon.
Browse the full list before you click through, then read on for a crash course in 12-volt battery technology, signs that it’s time to replace your current battery and tips toward making the new one last as long as possible.
12-volt car batteries 101
The final price quoted for a 12-volt auto battery usually includes a core charge. Often the core charge is added to the retail price at checkout, and other times it’s factored in, but it’s almost certainly there. Core charges are allowed in 50 US states and required in 30. They range from $5 to about $25, depending on the state and retailer.
When you get your old battery to a designated location, however it gets there, you’ll get the core charge back. The charge is intended to promote recycling, and it works. Automotive batteries are almost certainly the most recycled product on earth, with a hit-rate exceeding 99% in the US. East Penn Manufacturing, one of the big three 12-volt battery makers in North America, alone processes more than 30,000 old batteries daily. Moreover, virtually 100% of a battery’s content is reused. The 12-volt battery industry is the pioneer of true, large-scale recycling, and it remains the benchmark for recycling across a range of industries, including plastics, wastewater treatment and acid reclamation.
How do you know when you need a new car battery?
Clearly there are a lot of old car batteries out there, but the important question here is: How do you know when you need a new one, short of waking up one morning to learn that you can’t get to where you need to go? The answer isn’t as obvious as it once was.
There may be signs a car battery is on its last leg. Excessive corrosion around the post and battery cable connectors probably means it’s leaking acid. Some cars will flash the “check engine light” if the battery is weak, though in most cases you won’t know what that light exactly means without access to an OBD II scanner. An obvious crack, bulge or warpage in the battery case is a pretty good sign you should be looking for a new one.
Yet the conditions noted above are relatively uncommon, and their absence doesn’t necessarily mean a battery is healthy. Ten or 20 years ago, a battery’s decline would progressively show itself in one obvious way: increasingly slow and labored cranking or engine starting, particularly during a chill. A few recently manufactured batteries can still behave that way, but most modern batteries will continue cranking normally – until they won’t crank anymore.
“It used to be easier to tell when a battery was going bad,” says Rebecca Conway, senior director of marketing at Clarios (formerly Johnson Controls power), the world’s largest 12-volt battery manufacturer. “Modern batteries tend to continue cranking instantly until they won’t crank. The answer is a battery test. If your battery is 3 years old or older, get it tested annually. A lot of retailers will do it free onsite. It’s simple, and it’s the only way to be sure.”
A car battery needs two things: cranking power and reserve capacity. Cranking power is essentially the large jolt of electricity needed to start the engine. It’s measured as cold cranking amps, or CCA, or the amount of near-instant amperes a battery can deliver at 0 degrees Fahrenheit. Reserve capacity accounts for a smaller, slower electrical drain to feed things like lights or the radio when the vehicle is off and the battery isn’t charging. That’s measured in amp hours, or Ah, of total energy storage, and sometimes in minutes – how long a battery will provide power at a certain draw-down rate. Manufacturers rate their own batteries, and Consumer Reports lab tests have concluded that in real world conditions, batteries sometimes don’t match the manufacturer’s claim.
Regardless, the two requirements of a 12-volt car battery can actually work at cross purposes. A battery with enough cranking power to fire up a cruise ship won’t necessarily keep the headlights lit for 20 or 30 minutes. All car batteries are a compromise in this balance of cold cranking amp power and reserve capacity, and much of the technological development of the lead-acid battery over the last 152 years has been geared toward improving that balance.
What types of car batteries are there?
The great majority of car batteries are still lead-acid: lead plates of various designs saturated in sulfuric acid, which creates lead oxide and flowing electrons. The specifics of the technology have changed, but the chemistry remains the same.
The basic standard in 12-volt car batteries remains conventional “flooded” lead-acid. In these batteries, the lead plates are submerged in a bath of sulfuric acid. The majority of new cars and trucks still come with flooded lead-acid batteries, and most drivers will do just fine replacing them. A few still have removable caps that allow the electrolyte to be replenished by adding distilled water, but the great majority of current flooded lead-acid batteries are sealed. Nonetheless, there’s still a pool of sulfuric acid sloshing around inside. If the battery case happens to develop a small crack, the acid can drip out. If it’s tipped sideways, the electrolyte can spill out the vents.
The fastest growing chunk of the new and replacement 12-volt automotive battery market is Absorbed Glass Mat batteries. AGM was developed to improve that balance of cranking power and reserve capacity. The sulfuric acid inside is completely absorbed in matted glass fiber around the lead plates, so AGM batteries are essentially spillproof. AGM batteries are more resistant to vibration than flooded lead-acid and tend to have more reserve capacity for a given level of cranking amps. They’re less susceptible to damage from a really deep discharge (as in leaving your headlights on overnight in the garage), and that means potentially longer life. The downside? You guessed it. Other things equal – meaning size, cranking power and reserve capacity – AGM costs roughly twice as much as flooded lead-acid.
There’s one more type of automotive battery worth mentioning here, and it’s not a lead-acid traditional battery. While sales remain relatively tiny, lithium-ion battery technology has cracked the 12-volt car battery market. The dominant building block in these batteries is the alkali metal lithium, as opposed to lead, usually with an electrolyte of polymer gel or iron phosphate producing the necessary chemical reaction. Lithium batteries are more power dense than lead-acid, so they can meet a vehicle’s needs with considerably less weight (great for race cars). They could eventually prove to last longer than lead-acid batteries. And while all batteries self-discharge, meaning they slowly lose their stored power just sitting in the atmosphere, lithium batteries self-discharge much slower than lead-acid. With lithium, you could conceivably leave a vehicle sitting eight or ten months and start it without breaking out the jumper cables or battery booster. We wouldn’t try that with a lead-acid battery.
Just remember there’s no free lunch. You could buy about four flooded lead-acid or two premium AGM batteries for the price of a current lithium car battery. There’s also no developed infrastructure for recycling 12-volt lithium batteries as of now. In the meantime, there’s a strong likelihood that old ones will end up as trash.
What do I need to know when replacing a car battery?
The first thing you need for your 12-volt car battery replacement is the right group number. The battery size group number, or case size, prescribes basic dimensions agreed upon by vehicle and battery manufacturers. There are a few dozen group numbers for various vehicle applications, usually consisting of two numbers (24, 35, 49) or a letter and a number (H6, H8). The right group number ensures your new battery will fit the space your vehicle manufacturer has allotted for it, with the positive and negative posts on the correct sides and in the proper place to reconnect the battery cables. If you can’t find the battery group number in your owner’s manual, you can Google it, or simply look at your existing battery. It should be there somewhere.
Remember that the group number speaks primarily to case size. Cranking power and reserve capacity aren’t directly related. Car manufacturers typically recommend the minimum cold cranking amps for your model, and sometimes the reserve capacity in amp hours. Again, if you can’t find amp hour info in your owner’s manual, use the existing battery as your guide. We wouldn’t go under the manufacturer’s CCA and or Ah minimums, because even if it works fine the replacement battery will wear out faster. It’s generally safe to go over, though you’ll likely pay more.
Flooded lead-acid, AGM or lithium? Flooded batteries are great for starting and basic electrical needs. If a vehicle is 10 years old and driven regularly for moderate distances, there’s absolutely no reason that you need to upgrade to AGM from a regular battery. Other things equal, AGM batteries should last longer, but not necessarily longer enough to make up for the higher initial purchase price.
You’ll find a significant price spread even among conventional flooded lead-acid batteries. That can be attributed to three key factors: group number, rated CCA and reserve capacity, and warranty. If a brand offers a nice three- or even four-year full replacement warranty, you can be sure that will be reflected in the retail price.
If your car is a more recent vintage, and you plan to keep if for several years, and it’s loaded with features such as cooled seats, power liftgates, DVD players and a mega-watt audio system you like to play loud, you should probably be thinking about AGM – even if your car came from the factory with a flooded battery. If your vehicle is equipped with a stop/start auto-shutoff feature, you definitely want AGM. AGM car batteries are generally more heat resistant than flooded batteries (heat is no battery’s friend). They tolerate deep cycling, or deep drains of reserve power without significant charging, with less risk of long-term damage. We’ve recently seen used-car ads that note a replacement AGM battery as an upgrade or sell-up feature.
Many automotive battery brands offer two grades of AGM. We’ll call one standard grade and the other super-premium. Super-premium AGMs are marketed toward vehicles that operate in the most demanding conditions where failure is not an option – say, first-responder vehicles or serious off-roaders headed far from the beaten path, with electric winches and high-wattage auxiliary lighting. If you drive a luxury sedan or crossover with a lot of bells and whistles, you can probably stick with the standard grade.
Vehicle manufacturers are slowly rolling out cars and trucks that come standard with AGM. If that’s the case with your car, stick with AGM. It’s not that a flooded conventional battery won’t work – it will. But battery life probably won’t last long and it could create warranty issues. Some vehicles have battery sensors that detect the type of battery, and if an owner switches to another type, the control system may need to be reprogrammed to account for it. At the very least, consult your owner’s manual.
Lithium batteries have legitimate value if weight is a significant issue – as in a race car or even a track car – or if you’re a tech geek who just wants the latest. They can offer some interesting features, including fail-safes that won’t allow them to be completely drained. A lithium-ion battery can hold a usable charge sitting idle much longer than a lead-acid battery, and for some people that could matter.
Still, there are some AGM batteries that approach lithium in weight reduction for a lot less cash. Lithium may ultimately last longer, but if you can buy two or three conventional batteries for the same money, you’re not really winning in value. All you’re doing is delaying the point where you get under the hood to replace your battery. If you consider yourself the frugal, practical type, there’s probably no reason to buy lithium.
Car battery pro tips
Some 12-volt car batteries come with a built-in handle or removable strap. A handle would never be the biggest reason behind our buying decision, but its value shouldn’t be underestimated, either. With typical weights between 25 and 60 pounds, a car battery is hard to lift over a fender and into its spot.
Age is a big indicator that a 12-volt car battery might be on its way out, so you’ll want to know how old yours is. You’ll find its manufacture date on a sticker on the top or side of the case, but you need to know the code. In some cases, it’s a numeric designation with the month first and the year second, as in 11/20 for November 2020. Sometimes it uses an alpha designation for the month, starting with A for January and skipping the letter I, with a single digit for the year. In this scheme, our battery manufactured in November 2020 is an L-0. Yes, a battery with the same L-0 label could have been built in 2010, but you’ll probably be able to make a good guess.
The manufacture date matters when you’re buying, too. Ideally, you’ll want a new battery that’s less than three months old when you get it, because it’s almost certainly been sitting around discharging since it was built. Try not to buy one more than six months old. A longer discharge period than that means you’re not launching your new battery’s career on the most solid foundation.
Remember that old story about cleaning battery terminal posts with Coke? It’s not a crazy idea. Keeping posts and cable connectors clean and corrosion-free is never a bad idea, as it ensures optimum contact and performance. Drizzling them with Coca-Cola (or vinegar) is a good start, followed with a little light-duty lubricant.
Car batteries could make an interesting case study in branding. Everyone has their brand affinities, based on personal experience, performance, image or all of the above. Yet nearly all the 12-volt car batteries built and sold in the US come from either Clarios, East Penn or Exide, the main manufacturers. All of those car battery brand products – AC Delco, Deka, Diehard, Duracell, Duralast, Interstate, Mopar, Motorcraft, Odyssey, Optima and so on – are designed to each’s specification and built by one of the big three manufacturers.
Lab testing has shown that battery performance and life vary within model lines from the same brand. Consumer Reports will not make a recommendation based on specific brands or model lines because its test results vary across those model lines, and from year to year. A Diehard Gold, for example, may outperform a Duracell Advanced in one group number, but the Duracell may outperform the DieHard battery in another group number. And the test results can change for a specific group number over a year or two. You can’t be certain that buying the same battery you’re replacing will deliver the same results.
Perhaps the best advice for buying a battery is common sense. Choose a type that best meets your needs, a model that has your specifications and the price you’re comfortable with. Then make it last as long as you can.
Do 12-volt car batteries really wear out faster than they did 20 or 30 years ago? We found no objective data supporting that assertion. What’s clear is that demands on those good ole 12-volt batteries have increased exponentially over that period. The electrical draw from new systems and accessories in the typical automobile has tripled over the last decade, and it’s expected to double again over the next five years. The 12-volt battery is more critical to an automobile’s proper operation than it’s ever been, whether that vehicle is powered by petroleum, electricity or a combination of the two.
What causes car batteries to go bad?
One of the primary battery killers is beyond any individual’s immediate control, and it was the same 20 or 30 years ago. That would be climate, or at least ambient temperatures. No battery, whether it’s AAA alkaline, mobile-phone lithium or 12-volt automotive, likes extremes in temperature. They don’t like subfreezing temperatures, and they like 100 F even less. Automotive batteries, whatever the type, are going to generally last longer in Portland, Oregon, than in Alaska or Phoenix.
The biggest controllable threat to your battery’s life is excessive discharge. If the battery charge level drops to the point where you need a jump to start your car, you’ve already done damage. Allow that to happen multiple times and your battery won’t be long for this world. Put another way, the shallower the average discharge, the longer a 12-volt battery will last. Automotive batteries of all types last longest if they consistently stay near a full charge. That’s one reason it’s hard to over-battery your car. The larger the reserve capacity, the smaller a given discharge is, relative to the total available energy.
Car batteries don’t like sitting idle. Like all batteries, they self-discharge, and if they sit idle long enough they’ll go dead. In cold climates, discharging lead-acid batteries can freeze, and that’s never good for a long, productive life. Driving patterns play into the deep-discharge problem and can lead to a dead battery. If you use a car once or twice a week for errands that amount to a few miles, at relatively slow speeds, you could be building a discharge deficit. The car may not be running enough to fully recharge the battery, and the deficit can get bigger over time. It sounds odd that your battery didn’t last very long because you didn’t use it much, but it could be true.
There’s a simple solution to this discharge problem, of course, if it’s practicable to apply. That would be a battery maintainer or trickle battery charger, which feeds your battery a low-grade charge even when the car is parked.
If you park your vehicle in a garage, or within reach of an electrical outlet, you should use a trickle charger – especially if the vehicle sits for extended periods, and during winter. Trickle chargers are relatively inexpensive, and all but the cheapest will shut themselves off before they overcharge your battery (make sure of this). They’re easy to use. They can be attached to your battery posts with alligator-style clips, though many come with easily installed attachments that allow you to use them without lifting the hood (through a lighter socket, for example). No tool is more effective than a trickle car battery charger to ensure that your 12-volt car battery lasts as long as it possibly can.
If a trickle charger isn’t practicable to your circumstances, at least take your vehicle for a good, long drive every week or so.
“Clean the terminals, use a maintainer when that’s possible and get your battery tested at least once a year when it hits 3 years old,” says Conway. “That’s really all you need to do. But if you do those things, you can avoid the worst-case battery scenarios.”
Written by J.P. Vettraino for Roadshow