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The Best Battery Maintainer 2021

Best Battery Maintainer

When a car isn’t being used on a regular basis, the battery can begin to lose its charge because it’s not being topped up by the alternator. This is a common occurrence for those that own performance or classic cars that are only used on sunny weekends as opposed to every day.

To keep the battery safely topped up, you’ll need the best battery maintainer, which is the Battery Tender ® Plus 021-0128. It ensures the battery has optimum charge by automatically switching from full to float charging modes to prevent overcharging. However, if you need to charge multiple batteries and don’t want to have multiple devices, the NOCO Genius G4 is the best alternative.

Maintaining your battery’s charge level increases its lifespan and ensures the car fires up with ease when it’s used. This saves the hassle of using jumper cables or other methods of starting up your car with a flat battery.

In terms of rating the battery maintainers within this article, we based our recommendations upon our experience of using them on our own cars as well as many factors. These factors included their different modes, amperage options, cord lengths, safety features, warranty and value for money.

Table of Contents

Car Battery Maintainer Comparison

Battery MaintainerFloat ModeAmperage
Battery Tender ® PlusYes1.25 Amps
Schumacher SC1300Yes0.8 - 3.0 Amps
NOCO Genius G4Yes4.4 Amps
BatteryMINDer 1510Yes1.5 Amps
Optima Digital 400Yes4.0 - 12 Amps
NOCO Genius 5Yes1.0 - 10 Amps
Black & Decker BM3BYes1.5 Amps

You can have the best car battery on the market but if it’s connected to a car that’s not in use, it will eventually lose charge. Using a battery maintainer is the best way to keep it topped up and ensure it’s at max capacity.

Simply hooking up a standard charger that runs at full charging speed isn’t good for the battery. Overcharging causes a range of potential issues that may result in extensive damage to the battery. However, depending upon your budget, there are many premium car battery chargers that double up as a maintainer.

Below is a list of the best battery maintainers that safely keep batteries topped up to their maximum capacity.

The Best Battery Maintainer

1. Battery Tender ® Plus 021-0128

Battery Tender Plus 021-0128The Battery Tender ® brand is at the forefront of battery maintaining technology and the 021-0128 Plus is their most popular model. It has an impressive 10 year warranty and has many intuitive features that make it one of the best battery maintainers on the market.

One of those intuitive features is that the device is temperature compensated. This means no matter the temperature, it will adjust to ensure the battery charges to the correct voltage. Once the battery is fully charged, it switches to a float mode to keep it safely topped up.

Other features of the Battery Tender ® Plus 021-0128 include:

  • 1.25 amps
  • 6 foot AC cord length
  • 1.5 foot DC output cord length
  • Included battery ring terminals and alligator clips
  • Red and green light condition indicators
  • Spark proof and reverse polarity protection
  • Automatically switches from full to float mode

Overall, the Battery Tender ® Plus 021-0128 is the best battery maintainer that safely keeps the battery topped up at a safe storage voltage. The brand also state that it will charge as fast or faster than any other 3 amp battery tender on the market.

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2. Schumacher SC1300 Battery Maintainer

Schumacher SC1300 Battery MaintainerThe cheaper alternative to the Battery Tender above is the Schumacher SC1300. It’s a similar battery maintainer that also has a 1.5 amp charge speed but only a 1 year warranty. However, the brand also produce other high performing models to best suit your requirements.

According to the brand, their 1.5 amp battery maintainer in particular meets the highest industry standards and is also DOE compliant for complete peace of mind.

Other features of the Schumacher SC1300 Battery Tender include:

  • 1.5 amps
  • Float mode monitoring
  • Auto voltage protection
  • Reverse polarity protection
  • Automatically adjusts amp rate to charge or maintain
  • LED indicators to display charge status

The Schumacher SC1300 is the best cheap car battery maintainer that’s small enough to be kept discretely within any garage. One design feature that we really like is the hole at the top and bottom, which you can easily use for mounting near the battery.

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3. NOCO Genius G4 Smart Battery Charger Maintainer

NOCO Genius G4 Smart Battery Charger Maintainer
For those that are lucky enough to have a multi-car garage, maintaining all the batteries can be a difficult task. Not only will you require multiple maintainers but you also have to deal with wires leading all round the garage to each car. However, the best solution to solve this issue is the NOCO Genius G4, which is a 4 bank smart charger and maintainer.

It does come with a premium price tag but when you add up the cost of multiple battery maintainers, it works out as great value for the money. It also acts as both a smart charger and maintainer for all-round battery maintenance.

Other features of the NOCO Genius G4 Battery Charger include:

  • Various amperage options (0.75 to 26 amps)
  • 4 banks for charging 4 batteries simultaneously
  • Works with both 6 and 12 volt batteries
  • Spark proof and reverse polarity protection
  • Includes clamps, terminals and extension cables
  • 5 year warranty
  • Provide intuitive diagnostic information

Although expensive, the NOCO Genuis G4 is the best option for maintaining multiple car batteries. It’s also backed by a reputable brand and comes with an impressive 5 year warranty for complete peace of mind.

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4. BatteryMINDer 1510 Battery Maintainer

BatteryMINDer 1510 Battery Maintainer
BatteryMINDer is another reputable brand that produce a range of battery maintaining devices. The 1510 model in particular is an all-in-one device that acts as a charger, maintainer and battery desulfator for complete battery maintenance.

Also included with the battery maintainer is a 12 feet power cord, insulated battery clips, ring terminal assembly and other hardware.

Other features of the BatteryMINDer 1510 include:

  • 1.5 amps
  • Automatic high frequency pulse desulfator
  • Ability to maintain 4 batteries at once
  • FFC certified to meet strict energy efficiency guidelines
  • Ambient temperature sensor
  • Suitable for a variety of battery types

The BatteryMINDer 1510 is the perfect solution for maintaining a variety of batteries without breaking the bank. It also has the unique bonus of featuring an automatic high frequency pulse desulfator for restoring battery health.

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5. Optima Digital 400 12V Performance Maintainer

Optima Digital 400 12V Performance Maintainer
Optima are well-known for producing a range of vehicle batteries but they have also offer this charger and maintainer device. It’s known as the Optima Digital 400, which is more sophisticated than the alternatives and suited to professional garages or enthusiasts.

According to the brand, their battery maintainer is able to recover discharged batteries that other devices cannot. They state that if a battery is down to just 1.25 volts, the Digital 400 12V Performance Maintainer is be able to recover it with ease.

Other features of the Optima Digital 400 include:

  • 4 amps
  • Built-in battery health mode
  • LED charging indicators
  • LCD display
  • Hook and stand for mounting near battery
  • Spark free connection technology
  • Suitable for charging, conditioning and maintaining
  • Additional options for optima batteries
  • Can be used on marine or motorcycle batteries

The highly rated Optima Digital 400 is the ultimate device for maintaining, charging and recovering batteries. It’s packed full of intuitive features and has the backing of the reputable Optima brand for compete peace of mind.

If you require a more powerful version of this battery maintainer, the brand also offer a 12000 model. For the additional cost, there are extra features such as enhanced performance, a max amperage of 12A, USB charging port and much more.

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6. NOCO Genius 5 Car Battery Maintainer

NOCO Genius 5 Car Battery Maintainer
Another option by the NOCO brand is their new and improved Genius 5 battery maintainer, which is a successor of the G3500 model. Compared to its predecessor, it’s 34% smaller in size but is able to deliver over 65% more power.

It’s a completely automatic maintainer that prevents overcharging and includes many intuitive features such as automatic detection, integrated thermal sensors and much more.

Other features of the NOCO Genius 5 include:

  • 5 amps
  • Compact design
  • Dedicated repair mode
  • Thermal compensation optimized
  • Charges and maintains all types of batteries
  • Improved and high quality clamps
  • Reverse polarity protection

The new and improved NOCO battery maintainer is an excellent all-round option that won’t disappoint. It uses all the latest technologies and is suitable for all types of vehicles and their charging requirements. NOCO also offer other models of this battery maintainer but the Genuis 5 is the best option for most car owners.

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7. BLACK+DECKER BM3B Automatic Battery Tender

BLACK+DECKER BM3B Automatic Battery TenderBlack and Decker have been a reputable worldwide tool brand for many years and are well-known for their reliability and build quality. The BM3B follows that great reputation and is their fully automatic battery maintainer that’s ideal for those on a budget.

In terms of the compatibility of this maintainer, the brand state that it’s suitable for 6V, 12V, AGM, GEL and WET battery types.

Other features of the BLACK+DECKER BM3B include:

  • 1.5 amps
  • Charges both 6 and 12 volt batteries
  • Suitable for AGM, Gel and Wet batteries
  • Includes clamps and terminals
  • Automatically switches between charging modes
  • Built-in mounting bracket
  • Short circuit and reverse polarity protection

The smart charging technology of the BM3B model ensures the battery remains at optimal charge at all times. It automatically switches between full charging and float modes, which is fairly impressive for such a cheap device. Although there are similar priced models available, none have a reputable brand backing like the Black and Decker BM3B.

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How We Rated The Battery Maintainers

Over the years, we have tried and tested a number of battery maintainers. The Battery Tender has been our favourite but we also own the Optima Digital 400 too as shown in the image below.

best battery tender

As well as our experience of using a number of maintainers, we also based our recommendations upon a number of factors. The factors that we considered included their different modes, amperage options, cord lengths, safety features, warranty and value for money.

Battery Maintainer Buying Guide

Car batteries can be expensive to replace and without proper maintenance, it can become a regular expense for cars that are in storage. From race cars to classic cars, no matter how good a battery is, it will eventually lose charge if the car isn’t used.

A battery maintainer simply connects into a regular mains sockets and uses very little electricity in order to function. When powered up, you can then attach the connectors to your battery terminals in order to maintain the battery. This short video shows our top rated recommendation (Battery Tender® Plus 021-0128) in action.

To provide more knowledge with regards to battery maintainers, we have devised an informative buyers guide to ensure you understand which is the best option for your requirements.

Amperage and Different Modes

When it comes to choosing a battery maintainer for your car, you will notice that you have various amperage options. This is the amount of current it allows to flow from the device to the car battery with the higher rating resulting in a faster charge. In terms of generic battery charging, a higher amperage is more desirable but this isn’t the case with a battery maintainer.

High amperage maintainers will have different modes that allows you to choose the type of charging that you require. For example, some may require a “fast charge” and this can usually be selected from the interface of the maintainer. However, most people that are in the market for one of these devices will most probably leave it on a safe automatic mode.

Safety Features and Diagnostics

Due to the amount of electrical current coming from a car battery, it’s important that the battery maintainer is safe for the user and the car itself.

Safety features that you can expect to see include:

  • Auto voltage and amperage to prevent the battery overcharging
  • Spark resistant clamps to reduce spark when connecting to the terminals
  • Reverse polarity features to prevent connecting to wrong terminals
  • Short circuit protection
  • … and much more

Some of the high end models will even provide diagnostic information regarding the health of the battery. It won’t be as detailed as a dedicated car battery tester but it will certainly provide an indication towards the health of the battery.

How to Use a Battery Maintainer

Connecting the maintainer to your car’s battery is simple and very similar to connecting a standard charger to your car.

To safely connect it to your car, follow the below steps:

  1. Remove the negative and then the positive cable from the battery terminals.
  2. Have the battery maintainer plugged into a socket but not switched on.
  3. Connect the positive cable from the maintainer to the positive terminal.
  4. Connect the negative cable from the maintainer to the negative terminal.
  5. Visually inspect the connection to ensure that it will not come loose.
  6. Select the charging mode that you require on the maintainer.
  7. Switch on the socket powering the maintainer.
  8. Monitor it and ensure everything is working before leaving it.

Although there is quite a few steps, it’s fairly straightforward to get it up and running. If you are leaving the car for a long period (i.e. over the winter), then regular checks are advised. You can usually just take a brief look at the maintainer and check for a green light, which is an indication that everything is working fine.

Battery Maintainers v Trickle Chargers

As the term “trickle” may suggest, a trickle charger will apply a constant charge to the battery regardless of whether it’s fully charged or not. This is different to a battery maintainer as this will charge the battery until it’s charged. Once charged, it will switch to a “float mode” that only charges the battery once it detects the voltage has dropped.

As you can imagine, a trickle charger that’s connected indefinitely isn’t healthy for the battery. Once a car battery is fully charged, it should not have the same voltage sent to it constantly. Trickle chargers do have their uses but if you want to leave a charger in for long periods of time, a battery maintainer is the best solution.

Benefits of Battery Float Chargers

The benefits of battery maintainers that use float charging modes are fairly obvious. The main being convenience of having a fully charged battery in a car that has been stored for a long period. Although there are many portable jump starters that will jump start the car, it’s much easier and safer to keep the battery topped up using a maintainer.

On top of this, battery maintainers ensure the battery is charged safely at the correct voltage. This means the battery won’t become damaged from being overcharged or being drained multiple times. If you have just bought a new car battery, you want to ensure its kept healthy and a battery maintainer will do exactly that.


Using a battery maintainer comes with various benefits as stated above and ensures your battery is topped up. Many car battery chargers come with this functionality but using a battery maintainer that has one purpose, which is to maintain the battery is the best option. All of our recommendations above perform this functionality and are relatively cheap to purchase too.

The Battery Tender® Plus is the best all rounder but for those that have a large garage or simply want more functionality, there are alternatives. The Noco Genuis G4 and Optima Digital 400 provide further features that can transform how you maintain your batteries.

procarreviews author

Written By Dan

About the Author

Dan is an automotive journalist and owner of over 10 cars ranging from supercars, tuned cars, classics and your good old beater cars. He always likes to get his hands dirty with nut and bolt restorations or detailing sessions using the best products on the market.

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