Reviews

Best Battery Maintainers: Keep Your Car Battery In Prime Condition

Affordable, high-quality battery maintainers to keep your car battery healthy.

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BY Corrina Murdoch / LAST UPDATED ON July 23, 2021

The hidden hero in your car, the battery is essential to making your vehicle move. Of course, being important doesn’t make it invulnerable. Batteries lose charge when you leave the car parked for long periods, if the weather gets too cold, or it simply gets too old. While, eventually, you will need to replace it, you should get several years of use out of the battery. That’s where a battery maintainer comes into play.

Unlike a battery charger, it flows a slow amount of electricity into the battery, keeping it working. Protecting against overheating and surges, it feeds the battery without overdoing it. When used properly, and in conjunction with regular vehicle upkeep, you can optimize the lifespan of your battery and save big over time. To do that, you need to pick out the best battery maintainer for your vehicle. To assist, we’ve curated a list of the leading candidates, along with some tips on making your pick. Let’s get started.

Best Overall
Battery Tender Four-Bank Battery Management System
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Summary
Summary

Able to maintain four batteries at the same time, this precisely machined device automatically controls output voltage. Each port offers 12-volts at 1.25 amps. 

Pros
Pros
  • Works on all AGM batteries
  • Protected against reverse polarity
  • Microprocessor optimizes electrical flow
Cons
Cons
  • Comes at a fairly high price point
  • Better if you’re working with multiple batteries
Best Overall
Battery Tender Four-Bank Battery Management System
Best Value
Everstart 12-Volt Battery Charger and Maintainer
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Summary
Summary

Cost-effective and user-friendly, this battery maintainer works on any type of car or water vessel. Complete with O-rings and clamps, it lets you restore your battery quickly.

Pros
Pros
  • Affordably priced
  • Includes long cabling for easier connections
  • Encased in a durable polymer exterior
Cons
Cons
  • Cord connections can get strained easily
  • Vulnerable to extremely cold situations
Best Value
Everstart 12-Volt Battery Charger and Maintainer
Honorable Mention
Coleman Two-Watt Solar Battery Maintainer
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Summary
Summary

A unique approach to battery upkeep, this maintainer relies on solar power to restore your battery quickly. Installing easily, it mounts on your windshield and connects via a 12-volt plugin.

Pros
Pros
  • Two watt output
  • Powerful solar panels work even in poor weather
  • Works on ATVs, cars, and other large-battery systems
Cons
Cons
  • Suction cups require a clean, dry surface
  • Only comes with 8 feet of wire
Honorable Mention
Coleman Two-Watt Solar Battery Maintainer

Why Trust Us


Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks.

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Why Buy a Battery Maintainer

  • Extend battery lifespan. While all batteries die eventually, you should be able to get a good few years out of them. Battery maintainers help keep them working for even longer by keeping a proper charge at all times. Because you won’t need to continually boost it, the maintainer drastically slows wear and tear. 
  • Prepare for all seasons. The colder it gets, the harder it is for your battery to get going. It gets even more difficult if your battery isn’t strong enough for the task. A battery maintainer keeps the battery working so that when you need it, you’ll be able to start your truck with ease. 
  • Peace of mind. Heading out for a vacation and planning to park the truck in the meantime? If your truck’s battery is left too long without someone turning it over, it will lose functionality. Instead of arriving back home to discover a dead battery, you can plan ahead and hook it up to a battery maintainer. 
  • Restoring tired batteries. Battery maintainers can actually jolt a little life into old car batteries. If you have a few dead(ish) batteries kicking around your garage, consider restoring them with a maintainer-charger alternator. Many maintainers can safely return an old battery to its former glory. 
  • Safe on your battery. You don’t chew on coffee grounds—you let them trickle through a strainer and then get the zap charge. Batteries are the same. Instead of having a sudden blast of amperage, maintainers overcharge and surges. It safely lets your battery return to full charge, with no stress involved.

Types of Battery Maintainers

Single Bank Battery Maintainers

Easily the most prevalent type of maintainer on the market, these are designed for dedicated use on one battery. As a result, the options tend to be affordably priced. Modern versions include smart-chip microprocessors that are able to detect the requisite charge and meet that demand precisely. As with all battery maintainers, they use the multi-tiered charging approach in order to prevent overcharge and surges.

Multiple Bank Battery Maintainers

Popular in commercial settings and multi-vehicle households, these maintainers are designed to work with several batteries concurrently. Depending on the situation, you can find them with as few as one or as many as 10 banks. Tending to be more expensive, these also have the most durable circuitry. Each bank operates on a parallel wiring platform; so, if one of the banks loses its efficacy over time, you can easily compensate. 

Hybrid Battery Maintainers

Typically, this type is used for a more specific purpose than merely keeping a battery working. Hybrid maintainers typically double as battery boosters, working to recharge the battery and maintain it. Because of this design, you can take worn down lead-acid batteries and restore them by alternating the maintainer’s features. Keep in mind that a restored battery would likely require the ongoing tending of a maintainer. If you are restoring several batteries, keep this in mind. 

Top Brands of Battery Maintainers

NOCO

Founded in 1914, this company originally went by the name Nook & O’Neill. A privately held corporation, it focuses on innovating batteries, chemicals for the automotive industry, and electrical supplies. Based out of Ohio, NOCO retails products internationally. Amongst its most popular items for car batteries is the NOCO Boost Plus Lithium Jump Starter

Battery Tender

Opening its doors in 1965, this company started out as the Deltran Battery Tender. It focuses on crafting high-end technology for all types of batteries. Selling products internationally, it offers batteries for all types of vehicles. Among its supplies are battery maintainers, solar panels, and jump starters. One of its top selections is the Battery Tender Four-Bank Battery Maintainer.  

Everstart

With a wide range of batteries, Everstart’s claim to fame is marine supplies. Made by Johnson Controls, it has a large hand in car batteries, as well as batteries for ATVs and motorcycles. Starting with the innovation of Warren Johnson in 1885, it has grown into an internationally reputed name in energy conservation. The Everstart 12-Volt Battery Charger is one of their best battery maintainers.

Battery Maintainer Pricing

  • Under $100: Budget maintainers tend to be either charging and maintainer combos meant for portable use or single-bank maintainers that pack some useful smart features. Either way, this is a good range to consider if you simply want a basic maintainer.
  • $100 to $200: This range is full of advanced single-bank maintainers mixed with a few multi-bank options. Most multi-bank maintainers here are generally limited to four or five batteries at a time.
  • $200 and up: The upper range of battery maintainers is also fairly limited to professional-grade maintainers with large battery bank capacities. Maintainers up to 10 banks, for example, are common in this range. You'll also find the most user-friendly options here.

Key Features

Charging Ports

All battery maintainers will have at least a single port; however, if you are looking to tend more than one battery, you’ll need a maintainer with more capacity. First, check the quantity and ensure that there is enough room to handle your needs. Next, look at the circuitry to ensure that the stations are wired independently from one another. This feature serves to prevent electrical overlap and stop batteries, being charged simultaneously, from pulling power from each other. 

Amperage Supply

Amperage is a measure of current, meaning it tells you how strongly the electricity is flowing into your battery. Most ring in at around two amps. Now, higher might sound better, but with a maintainer, it’s better to stick in the mid-range. Too high, you get an overcharge. Too low, there’s no result. Maintainers are designed to fall right in the middle, providing the ‘just right’ amount of electricity to the battery. If you plan to get a hybrid for use as a charger, make sure that there are ample safeguards and a well-structured charging approach. 

Charging Approach

The vast majority of battery maintainers on the market use the four-step charging approach. The first is initialization, basically when the unit starts up and connects with the battery. The microprocessor detects the necessary charge and it moves to step two: bulk charge. This is when a heavy, steady flow of electricity goes into the battery. Once the battery hits 80 percent full, it moves to tier three: absorption. Now, a steady voltage flows in, but the system titrates down the amperage. The final state is float mode. Basically, the float mode sets it so that a current only applies when the battery needs it, thus preventing overcharging. 

Safeguards

Another important feature is the safeties in place. Modern versions tend to incorporate the most safety features, having learned the pitfalls along the way. Keep your eye out for overcharge and short-circuit protection, features built into the microprocessor. Additional safeties include voltage and amperage limits, as well as protection against reverse polarity. Provided these safeguards are in place, and the attachment hardware is in good condition, it should be a safe maintainer to use on your car battery.

Other Considerations

  • Durability and maintenance. It might sound counterintuitive for a battery maintainer to require upkeep, but every car accessory needs TLC sooner or later. Though it does most of the work for you, checking its attachments and assessing performance is important to keeping it in good working condition. Opting for smart-chip versions mitigates a lot of this work, since you can simply do a visual check of the attachments and be good to go. 
  • Extra features. Depending on everything from your car to the climate, you’ll need different features out of your battery maintainer. Some feature a powerful bulk charge mode, letting you use it both as a maintainer and a charger. Here is where the smart components are really important, though. Without them, you run the risk of surges. Check that the maintainer is designed to double as a charger to avoid damage to your battery. 
  • External protections. The interior components of the circuitry handle the bulk of the machine’s safety needs. However, they can’t address outside circumstances. As a result, you need a maintainer that is sturdy. Ideally, it is easy to set down and built to breathe well such as to prevent overheating. Both the internal and external design features are essential to optimizing safety. 

Best Battery Maintainers Reviews & Recommendations 2021

Best Overall
Battery Tender Four-Bank Battery

Especially for those looking to improve the health of multiple batteries, the Battery Tender Four-Bank Battery Management System is a fantastic candidate. It is able to accommodate four batteries at any given time, with each port electrically independent. Lightweight and compact, this 3-pound battery tender provides a steady 1.25 amps to efficiently yet safely restore charge. The high-tech system is built to automatically adjust the output to a float setting once it hits the ideal charger. Since it has thorough safeguards against overcharging, it takes all the guesswork out of restoring your battery. Well-suited to sealed batteries, you can use it on most automobiles. Equipped with a reverse polarity safety, there is no risk of damage. Built to exceed United States safety regulations, this is a high-end battery maintainer that is designed to last. 


It’s worth a note that, since this unit is so powerful, it does come with a proportionately higher price tag. That said, if you have more than one vehicle, it is a perfect garage companion. 

Best Value
Everstart 12-Volt Battery Charger and Maintainer 

Keeping your car battery working shouldn’t drain your bank account. That’s what makes the Everstart 12-Volt Battery Charger and Maintainer such a popular option. It is priced affordably and is extremely compact. Though it has a straightforward design, it can perform all the necessary functions. Equipped with clamps and O-rings, this automatic one-amp battery maintainer works in any situation. It’s compatible with any standard lead-acid battery, meaning you can use it on both land and water vessels. Since this model includes lengthy cable, you can connect it from just about anywhere. At the center of the device is a simple piece, highlighting battery charging status with light indicators. Easy to use and extremely affordable, this charger and maintainer is a worthy value pick. 


If there was one thing with which we take issue, the cord attachments to the charger are a bit flimsy. Easy to bend, you can damage the circuitry easily if you tug on the cord. As long as you’re able to handle it with care, though, it is built to work for long periods.

 

Honorable Mention
Coleman Two-Watt Solar Battery Maintainer

As the world becomes increasingly aware of the long-term impacts of carbon, new tech hits the market to rise to the occasion. That’s precisely what the Coleman One-Watt Solar Battery Maintainer does. Instead of being bulky and chemically based, this 12-volt system attaches to your windshield through a suction cup. The amorphous system is able to draw power even in lousy weather. You can plug it into your 12-volt port or connect it directly to your car’s battery with the included clamps. Constructed using ABS plastic, this solar panel is able to run a reliable charge without the potential of overcharging or surges. There is no risk of damage to the battery of your car’s electricals. Versatile and reliable, this solar battery earns an honorable mention for its clever approach to maintaining batteries. 


Keep in mind that this maintainer is far from waterproof. It only works when you put it on the inside of your windshield and can get damaged by water easily. However, with 8 feet of wire, you can easily connect it to most vehicles.

Honorable Mention
MOTOPOWER Automatic Battery Charger

Durable and versatile, the MOTOPOWER Automatic Battery Charger is a jack of all trades in the world of maintainers. Ideal for climates where the weather continually impacts battery performance, this model can be used as a trickle charger, desulfator, and battery maintainer. Compatible with 12-volt lead batteries, AGM, and gel cell batteries, this charger is safe to use in just about any situation. To desulfate (fix damage from undercharge), it sends a pulsing current to free your plates from the buildup. 


Fitted with safeguards, after the charge is complete, it returns to float mode. The maintainer prevents issues with overcharge, shorts, and reverse polarity. A simple, plug-and-play design, you attach it to the battery and it goes right to work. With an impressive five-tier charging approach, it diagnoses, starts slow, moves through the bulk, absorption, and float state. You can use it on batteries of all sizes and types, including those on motorcycles and off-road vehicles.


The only significant drawback is that, when compared with other models, the cord length leaves something to be desired. In terms of performance, it’s a great pick. Be sure, however, that you can reach the battery and attach the maintainer safely before you make your pick. 

Honorable Mention
BLACK+DECKER BM3B Fully Automatic 6V/12V Battery Charger

This streamlined Battery Maintainer will charge and maintain 6 and 12 volt batteries. It works best with GEL, AGM, and wet cell batteries. This tender will actively charge your battery until it’s fully charged. It will then automatically switch to maintenance or float mode to maintain your battery. There’s a light indicator to tell you the status of your battery. It has a built-in mounting bracket so you can choose a permanent placement for your tender. 


You can easily connect this to any battery with either the clips or the O-ring terminals. This makes it easy to use this tender with several different vehicles. This tender also comes with several safety and battery saving features. These include protections like reverse polarity, overcharging, and short circuiting. 


Unfortunately, the circuit board and screws holding the unit together are prone to corrosion. This will render the unit useless. This unit also has a tendency to randomly fail after a day, a few weeks, or several months of use.

Honorable Mention
Schumacher SP1297 12V Fully Automatic Battery Charger and 3A Maintainer

This battery charger will effectively charge and maintain your car, motorcycle, or marine battery. It delivers a 3A charge that’s controlled by a microprocessor. It uses multi-stage charging to protect and extend the life of your battery. You connect it to your battery using the included clamps. 


The charger has reverse polarity protection in case you hook it up wrong. This is an important safety feature that will protect you, your battery, and the maintainer. It comes with a hook attachment that lets you hang it outside of your work area. This charger can also effectively charge and maintain lithium (LiFePO4) batteries. 


Unfortunately, this is not a fully automatic charger. You’ll need to tell it what type of battery you’re connecting it to. You’ll also need to reset it if the power goes out while you're charging. It also won’t charge 6V batteries, as claimed.

Honorable Mention
CTEK MXS 5.0 Battery Charger and Maintainer

The CTEK MXS 5.0 Battery Charger and Maintainer is designed for automotive and motorcycle use. This advanced microprocessor-controlled charger includes a reconditioning mode and is ideal for use with lead-acid batteries. Other features include battery diagnosis, automatic desulfation, and a float/pulse system that efficiently maintains the battery when it's connected for long periods of time.


The device has a built-in automatic temperature sensor and comes with alligator clamps and eyelets. It's splash and dust-resistant and protects against sparking, reverse polarity, and short circuiting. It has an easy-to-read LED display, is perfect for start-stop systems, and comes with a five-year warranty. Users report that it's small, light, and easy to use.


There have been some complaints that it can get warm to the touch. Also, the instructions aren't very detailed, and the electrical cord isn't very long.

Honorable Mention
Schumacher SP-200 2.4W 12V Solar Battery Charger and Maintainer

This solar-powered battery charger and maintainer uses the power of the sun to charge your vehicle battery. It works in both full sun and cloudy conditions. The unit is water resistant and comes with clamp connections to attach it to your battery. It’s ideal for boats, motorcycles, snowmobiles, cars, trucks, and RVs. It will maintain a 12V lead-acid battery. 


This charger and maintainer doesn’t need electricity to work. It’s also rated for indoor and outdoor use. This gives you complete freedom in how and where you use this battery charger. 


Unfortunately, this charger and maintainer doesn’t put out enough power to keep the battery charged if you have other components in your vehicle using the power. This means it won’t be effective on modern or higher-end vehicles that have a lot of electricity-demanding features. The fact that this unit is solar also makes its charging ability spotty since you’re dependent on the sun for it to work. While you can use it outside, it isn’t waterproof, so exposing it to rain or snow will ruin the charger. There is also no indication of whether the unit is working or not.

Honorable Mention
Battery Tender JR High-Efficiency Battery Charger

While it might be modeled against a standard trickle charger, the Battery Tender JR High-Efficiency Battery Charger performs far more advanced functions. This 800mA charger is designed to automate battery preservation. The included microprocessor is able to detect the optimal charge of any battery and provide it with the precise amount of electricity it requires. After reaching that state, it returns to float mode. Incorporating LED indicators for ease of use, this set also comes with all the hardware you need to get it up and working. A 12-foot extension cord lets you connect from anywhere. The alligator clips and O-rings make attachment easy. With a four-step charging setup, it quickly initializes, moves to bulk charge, shifts to absorption settings, then returns to float. Safe and reliable, this battery maintainer works on all types of vehicles. 


It’s worth a mention that, while the cord is long, it is not very tough. All the other parts of the maintainer are sturdy, but its physical connection where the cord meets the plastic casing is easy to damage. Store it securely and avoid tugging on the cord to help it work for longer.

Tips

  • Store it in a safe space. Your battery maintainer is vulnerable to overheating and impact damage, all of which can damage its abilities. Take care of it to maximize utility. 
  • Use it regularly to get the full benefits of the maintainer. If the temperature drops or the car will be out of use, the maintainer can pick up the slack. 
  • Keep it simple. Aim for a simple ‘set-and-forget’ model where you plug it in and leave the maintainer to do its work. 
  • Look for smart features such as smart charging. If it automatically turns off and on, then there is a lot less to worry about.
  • Focus on models that are easy to use. The best battery maintainers set up quickly and perform for a long time. 
  • Take a moment for safety. From overheating to overcharging, any time you deal with electricity, safety must be on your mind. Familiarize yourself with the instructions before you get to work. 
  • Think about the requisite output. The more electrical output, the faster the work potential, but the risk of wear and tear increases. When it comes to battery maintainers, slow and steady wins the race.

FAQ

Q: What does a battery maintainer do? 

Battery maintainers keep your battery at full charge. They also help the battery last for longer. A battery maintainer detects the charge needed by your battery and determines the correct amount of current required. By restoring and maintaining optimal levels in your battery, the maintainer can really stretch out its shelf life. 

Q: Can you leave a battery maintainer on all the time? 

Yes, you can. Unlike a battery charger, a maintainer will stop pushing a charge once the battery is full. While a charger will overcharge it, the microprocessor technology in a battery tender ensures that there is no circuitry damage. It can actually improve the health of your battery if left on consistently. 

Q: Is a battery maintainer the same as a trickle charger? 

While they are similar, a battery maintainer is more advanced than a trickle charger. Maintainers adjust the flow of electricity based on the battery’s state and are able to shut down or return to float settings. Trickle chargers simply push a small current through the battery at a steady rate. They can help, but can’t quite live up to the standards of a battery maintainer. 

Q: Will a battery maintainer charge a dead battery? 

No, a battery maintainer does not carry the power necessary to charge a dead battery. It can keep a live battery from dying, even if it has a low charge. However, if the battery is completely drained, you would need a boost. From there, you can apply the battery maintainer to prevent it from losing power in the future. 

Q: How do I know if my battery is dead?

The first sign will likely be a check engine light, and a slow decline in performance. If your car starts then dies right away or simply won’t start at all, it’s likely the battery. If you can get the lights going but it won’t turn over, that’s a battery problem. The older your battery is, the more likely a culprit it is. A maintainer is better prophylactic, though you can try a hybrid model to boost and then sustain the battery. 

Q: How long does it take to charge a battery?

To get a battery from zero to full, using a regular charger at between four and eight amps, it would take between 10 hours and a full day. If you use a boost first, then you can tackle the job in under four hours. A maintainer uses an average of two amps. It is meant to attach to your battery and prevent you from dealing with the hassle of recharging it every time you need the battery. 

Q: Why is under or overcharging a battery an issue?

If you undercharge your battery, sulfur builds up on the plates, limiting the battery’s performance ability. Overcharging is worse. It results in excess oxygen and hydrogen building up. If the battery’s vented, then it wears away at the sides and exposes the plates. If the battery is sealed, it could rupture. Battery maintainers are designed to prevent these issues and keep your battery healthy. 

Final Thoughts

Now that you know the finer points of battery maintainers, you can make your pick. It could be the Battery Tender Four-Bank Battery Management System, a reliable and powerful option. You might prefer the Everstart 12-Volt Battery Charger and Maintainer, a cost-effective pick that works wonders.