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Best Battery Maintainer – Buying Guide and Top Products in 2020

Car battery trouble can be a major inconvenience. Many of us have had to jumpstart a car – our own or someone else’s – at least once in our lives.

If you own a vehicle that isn’t driven very often, the risk of your battery becoming totally flat increases. In this case, a little maintenance can go a long way toward preventing this sort of trouble.

In this article on the best battery maintainers, we discuss the relative merits of owning and using this preventative piece of equipment to keep your vehicle batteries in tip-top condition, even after months or years of no use and storage.

Battery maintainer cables transferring power to a battery still in the engine compartment

Below, you’re going to learn what a battery maintainer is, what these gadgets do and how you could benefit from using one.

We discuss what separates a battery maintainer from a charger, what you should be keeping in mind when shopping for one of your own, and end by taking a detailed look at what are, in our opinion, some of the best battery maintainers available on the market for you to choose from.

Quick Links to Our Top Recommendations for Best Battery Maintainer

Note: Clicking the above links will take you to further information, current prices and customer reviews on Amazon.

What is a Car Battery Maintainer? Why Might You Want One?

Also known as a tender, this is an instrument that works to maintain unused batteries, prolonging how long a car battery lasts. A maintainer senses how much (or how little) charge is required to keep a battery in good shape, automatically stopping power delivery when a full charge is reached.

Let’s say you’re the proud owner of a classic car or a recreational vehicle. I’ll go out on a limb and assume that you don’t use it for your daily commute to and from work. Am I right?

At the same time, you may not be able to take a leisurely drive every day, perhaps for maintenance reasons or in the case of inclement weather. This means your vehicle might spend weeks or months at a time in storage. Which, in turn, can result in a depleted battery; having a maintainer can be a big help.

The capabilities of battery maintainers will vary. Almost all offer bulk charging for when the power supply is nearly or completely drained. The highest amperage and voltage is put out by these gizmos when they are on bulk mode.

Some models provide floating charges. This refers to the fact that the voltage going into unit declines as it gets closer to 100 percent.

Others offer absorption charges. Amperage will decline while voltage stays steady once the cells are almost at 100 percent. This usually starts to happen when you’ve reached between 80 and 90 percent capacity.

Additionally, some brands can alert you when they identify problems. They can diagnose when it may be time for a replacement, or warn you of other issues.

With the best battery maintainer, you can rest assured your vehicle will start up without an issue. That is, of course, as long as everything else in your vehicle is in working order.

Without one, you may find yourself having to source a battery charger and giving your car a jump start. Worst case scenario, you might have to buy a replacement battery—and car batteries don’t come cheap.

How do Car Batteries Work?

Now that you understand what a maintainer or tender does, let’s delve into how the cells in your vehicle work. This is a chance to get familiar with the basic terminology if you don’t already know it.

Two Different Types of Cells

First of all, there are two broad categories of power units or cells. These include primary batteries, and secondary or storage.

The first type is disposable, like what most of us use in our remote controls. Once they’re out of juice, we toss them in the trash.

Our vehicles are equipped with the second variety. Secondary, or storage batteries, are rechargeable.

Cathodes, Anodes, and Electrolytes

All batteries, regardless of size or type, have similar principles of operation. There is a positive plate (cathode) and a negative plate (anode). The collective term used to describe the cathode and anode is “electrodes.” These two terminals must be kept separated.

Typically, the electrodes are immersed in a substance that allows electricity to be conducted between them. This is referred to as an electrolyte. This arrangement produces electromotive force and electric current, measured in volts and amperes, respectively.

All of this is kept inside a structure to protect it from the elements. In many cases, electrolytes are toxic substances that must be kept contained anyway. The electrolyte material and placement depends on the purpose of the unit. The same goes for the size and number of cells within the unit.

Lead Acid

A common type of car battery is lead-acid. The name is derived from the materials it’s made from. The walls are made of lead, and the electrolyte is sulfuric acid, giving the name: lead-acid. The fluid can be in liquid or gel form, depending on the type.

If the battery uses a gel electrolyte, it’s known as valve-regulated lead acid (VRLA). These have also been given the moniker “maintenance-free,” as water loss is less of an issue.

There are also absorbent glass mat (AGM) models. These make use of fiberglass mat so that the electrolyte can’t spill. This type will work faster and is more resistant to extreme temperatures than other types.

Lead-acid models of any sort are a great choice for automotive use for a few reasons. They have a lengthy lifespan, high voltage capacity, and are easy to build.

Sli Power Units

Most gasoline and diesel vehicles use so-called “SLI” power units. SLI stands for start, light, and ignition.

The roles of car batteries are simple but essential. Powering your interior lights and windows is just the beginning. They also run power to the starter, which gets your engine running.

Afterward, the alternator will take over. The alternator supplies the continuous power for your headlights, and pretty much every other electric-run component in your car.

You may be wondering why the alternator is necessary at this point? It’s because SLIs are intended for shallow rather than deep discharges. If the SLI had to keep everything in your vehicle running alone, it would run flat quickly. That’s what happens when you leave your headlights on all night, for example.

Instead, SLIs provide maximum currents over short bursts of time.


The majority of lead-acid SLIs are 12-volt. These are suitable for most types of light trucks, sedans, and SUVs.

Heavier vehicles like load-bearing trucks or construction equipment are different. They need more power, often using 24-volt instead.

Hybrid and fully electric vehicles often make use of lead-acid SLIs. Other variations include lithium-ion, ultracapacitors, and nickel-metal hydride.

As you can see, there is a range of options on the market. The specific type you have under your hood will be based on the make, model, and year of your vehicle.

What Causes Battery Depletion?

There are a couple of things that can result in depletion. Extreme temperatures—cold or hot—are a very common cause.

Human error is another frequent culprit. For instance, forgetting to switch off your headlights or leaving an interior light on overnight.

Frequent, short discharges can deplete batteries as well, such as constant short journeys. Some people can do this during the winter months, too, when they aren’t driving their vehicles.

By running your engine for a brief period and then switching it off, the alternator isn’t taking much of the load off. In the end, all you’re doing is discharging, not maintaining.

Repeatedly overcharging is another bad idea. You could accidentally cause sulfation, which can be a death sentence for the battery.

Sulfation occurs when lead sulfate crystals build up in the electrolyte fluid. In turn, this will impede electrical conversion. In VRLA models, overheating due to excess charge can encourage corrosion and water loss.

Age, corrosion, or defective alternators are other possibilities. If you can’t seem to hold a charge, no matter what, you might want to take your car to a mechanic. The problem may not actually be with the battery itself.

What is the Difference Between a Battery Charger and a Maintainer or Tender?

Tenders and chargers are not the same. A maintainer, tender (or trickle charger) is more refined in how it works.

This is not to say that chargers are to be avoided. However, there are circumstances where using a tender is a better option.

As we mentioned earlier, they’re equipped with sensory mechanisms. This means energy is transmitted as needed. It stops delivering once a full charge is attained. If you’re going to be leaving your car out of action for a while, this is practical.

On the other hand, chargers can work indefinitely. You have to monitor what’s going on—there’s no automatic switch-off.

If you leave a charger hooked up continuously, this can result in overcharging if you aren’t careful. Remember that overcharging is one of the things that can contribute to a shorter battery lifespan.

What to Consider When Buying a Battery Maintainer

Now you know what these gadgets are for, you’re likely eager to start shopping. We suggest you take a moment to read this buyer’s guide.

You want to get your purchase right the first time, and there are safety and compatibility features you should be aware of.

Types of Battery it Can Maintain

There are many types of car batteries available. When you’re looking at maintainers, make sure to check for compatibility. Consult your owner’s manual if you aren’t sure what battery type your vehicle has.

Is the tender you’re considering suitable for gel or fluid? Is it appropriate for lithium-ion, lead-acid, or both? Again, be sure!

Amperage and Voltage

What voltage is the tender you’re considering rated for? If your car runs off 12 volts, a 6-volt maintainer will be useless.

What about peak amperage? If the current is too powerful, you run the risk of damage. Too weak and the gadget will take forever to deliver a full charge.

How Many Batteries Can it Maintain at Once?

This applies to those of you with more than one vehicle in storage. Why purchase two or more products? You can look for a tender that’s capable of trickle charging more than one car or truck at a time.

Number and Type of Charging Modes

Some products are better equipped than others. If you’re looking for a no-frills piece of equipment, you can choose one with limited functions.

If you want something more, look at devices that have a wider range. Is it able to sustain floating and absorption charges? What about bulk?

Ideally, a maintainer should be adaptable. The better it can compensate for changes, the less likely it is to do harm.

Diagnostic Features

If you want to head off trouble before it begins, you may appreciate a model that has diagnostic features. This way, you can take action to address potential complications.

You’ll be able to learn if your battery is discharged, defective, is saveable or needs replacing, with all the guesswork removed.

Safety Features

When you’re dealing with electricity in any form, safety is a priority. A good quality maintainer should have most or all of the following safety features:

Spark Resistant Clamps

Spark-resistant clamps lower the chances of fire. You don’t want sparks flying in and around your engine.

Most spark-resistant materials are able to spark, but the sparks are not hazardous. They’re not hot like regular sparks, so you don’t have to panic if you see any.

Short Circuit Protection

This will prevent damage to the maintainer and your battery in the event it gets overloaded. Without short circuit protection, it will continue operating and risk overheating.

Auto Voltage and Amperage

This auto-feature enables the gadget to adapt voltage and amperage levels. For example, lowering and controlling output as the charge nears 100 percent.

Reverse Polarity Features

This is handy for those of you who may worry about making mistakes connecting their batteries.

There are two terminals on a battery, negative and positive. In simpler maintainers, there is one cable suited for each one of the two terminals, and they’re not interchangeable. If you attach a cable to the wrong terminals, the consequences can be serious.

You could blow fuses or even destroy major components, like your alternator. If you make an error with the connections, the tender won’t work correctly at the very least. It’s equipped to charge only when correctly connected.

With reverse polarity protection, this isn’t a problem. You can eliminate the risk of damage by looking for a unit that has this feature.

Override Switch or Button

An override switch will let you take over rather than have the device work automatically. If you want to program the device manually, you have the option to do so.

Price and Value

Be wary of low-prices; you don’t want to endanger yourself or your automobile. Look at the overall value of the product compared to the price.

Will you be getting extra accessories, like a spare cable? How many modes of operation does it have? What about crucial safety features, such as short circuit protection?


A warranty is always beneficial when it comes to automotive equipment. It’s also an extra measure of security in case your product arrives damaged or defective.

With anything containing either electrical or mechanical components, you want a good manufacturer backed warranty because it shows they themselves have confidence in the quality, effectiveness, and longevity of their products.

No warranty? Avoid the product if you ask me.

Best Battery Maintainer – a Detailed Look at Our Top Recommendations

We’ve detailed our top recommended battery maintainers on the market. We hope you find one to meet you and your vehicle’s needs.

Deltran Battery Tender Junior 021-0123 12v, 0.75a Charger

Battery Tender Junior Charger and Maintainer: Automatic 12V Powersports Battery Charger and Maintainer for Motorcycle, ATVs, and More - Smart 12 Volt, 750mA Battery Float Chargers - 021-0123

If you have a small car or other small vehicles in storage, Deltran’s lightweight maintainer will appeal to you. It’s rated to work on any 12-volt lead acid battery. This device can charge as well as maintain cars, scooters, jet skis, motorcycles, and ATV’s.

Everything you need to get started is in the box. You’ll receive clamps and a cord. As the clamps are spark-proof, you won’t have to worry about accidental contact. It also

has reverse polarity as a safety precaution.

An advantage of the Tender Junior is the four-step automated program. It will sense the needs of your battery and adapt to compensate.

The steps include initialization, bulk, absorption, and float mode. Regardless of what state your power unit is in, you can set and forget this device. It has a quick-disconnect harness for convenient detachment.

Diagnostic readings are delivered through an LED light system. The descriptors of each (e.g. red, green, flashing) are on the side of the gadget itself. You won’t have to dig around for the instruction manual while you’re learning to use it.

Features and Specifications

  • Amperage: 0.75 amps.
  • Compatible with all 12-volt AGM or gel lead-acid batteries.
  • Single-battery maintainer.
  • Spark resistant; reverse polarity and overcharge protected.
  • Four-step charging program.
  • LED indicators.
  • Includes 12-foot output cord, harness, alligator clamps, and ring terminals.
  • 5-year warranty.

What We Like

  • Long warranty.
  • Adaptable modes.
  • Portable.
  • Simple to connect.
  • Designed with essential safety features.
  • Accessories included.
  • Easy to read display.

What We Don’t Like

  • Display is somewhat simplistic.
  • Not rated for use on larger vehicles (e.g., SUVs, trucks, etc.)


The Deltran Tender Junior is user-friendly and portable for small vehicle and car owners. The 5-year warranty and security features are additional enticements.

If you’re curious to know more, click the link below:


Click to Learn More / Buy from Amazon


Deltran Battery Tender Plus 021-0128, 1.25 Amp Charger

Battery Tender Plus Charger and Maintainer: 12V, 1.25 Amp Powersport Battery Charger and Maintainer for Motorcycles, ATVs, UTVs, and More - Smart 12 Volt Automatic Float Chargers by Deltran - 021-0128

This Deltran Tender Plus is for those of you with heavily upgraded cars. As with the Deltran Tender Junior model reviewed above, it’s suitable for cars and most popular small vehicles.

If your car has lots of electronic additions (e.g., aftermarket alarm), you may want to try this maintainer. The same goes for users who continuously make use of their automobile’s electronics.

The Tender Plus compensates for constant drain by charging rapidly. It provides 1.25 amps of delivery to ensure your power unit stays at 100 percent. Then, it sustains that on storage mode (similar to a floating mode). Two large LED lights will tell you whether the gadget is charging (red) or on storage (green).

Designed to be temperature resistant, it is resilient to harsh climates. Users have reported that it can withstand low and high temperatures alike. The box includes all the necessary accessories. The harness can be attached and removed effortlessly.

If you’re using it for maintenance purposes between rides, this is helpful. A poorly-made attachment mechanism can be frustrating to handle regularly, though.

Features and Specifications

  • Amperage: 1.25 amps.
  • Suitable for 6-cell lead-acid batteries, 1.2 to 200 Ah.
  • Spark resistant; overcharge and reverse polarity protected.
  • LED indicators.
  • Includes harness, ring terminals, power cord, and alligator clamps.
  • Single-battery maintainer.
  • 10-year warranty.
  • Weight: 3 pounds.

What We Like

  • Required equipment included.
  • Simple to attach and read.
  • Powerful charging ability.
  • Safe to use.
  • LED lights are easy to read.
  • Temperature resistant.
  • Generous warranty.

What We Don’t Like

  • Clamps can be tricky to attach.
  • After 90 days, buyer is responsible for return shipping costs to receive warranty.
  • Basic display.


The Tender Plus is excellent for car owners with battery-draining electronic features. It also doubles as a charger for when your vehicle is running low on juice.

If you want to buy one for yourself, follow the link below:


Click to Learn More / Buy from Amazon


Noco Genius G3500 6v/12v 3.5a Ultrasafe Smart Battery Charger

NOCO Genius G3500 6V/12V 3.5 Amp Battery Charger and Maintainer

The NOCO Genius G3500 will appeal to those of you with a lot of vehicles or other motorized equipment to maintain. It can be used with six and 12-volt batteries of nearly every variety.

It also comes with a range of modes. You can set it on cold/AGM mode for when the temperature drops. Or, you can use it on high voltage to repair discharged cells.

You may find that a battery you thought to be expired still has life in it. The high voltage pulses work to combat sulfation and other effects of disuse. The monitor will tell you whether you’re at 25, 50, 75, or 100 percent.

There are LED lights marked under different types (12 volts, 12 volts AGM, etc.). This is practical since it has so many applications. On the same note, individuals who aren’t car-savvy should find the NOCO Genius G3500 simple to use.

Despite all the options for various modes, the display isn’t complicated. In case you’re still unsure, the package includes explicit instructions.

Features and Specifications

  • Amperage: 3.5 amps.
  • Also available as 0.75, 1.1, 4-bank 4.4, 7.2, 15, and 26 amp.
  • Suitable for six and 12-volt batteries.
  • Compatible with lead-acid, wet-cell, gel-cell, lithium-ion, calcium, and all maintenance-free batteries.
  • Single-battery maintainer.
  • Spark-resistant, reverse polarity and overcharge protected.
  • Includes clamps, terminal connectors, and power cord.
  • 5-year warranty.
  • Weight: 1.86 pounds.

What We Like

  • Comprehensive monitor and modes.
  • Versatile.
  • Can repair damage.
  • Lightweight, easily transportable.
  • Long warranty.
  • Explicit guidelines for the inexperienced.
  • Quick charging.

What We Don’t Like

  • Users have occasionally reported receiving faulty products.
  • After 2.5 years, warranty doesn’t cover full value.


If you have a multitude of power units to maintain, the NOCO Genius G3500 is for you. Vehicle owners of all experience levels can appreciate the user-friendliness of this model.

If you want to see it for yourself, click the link:


Click to Learn More / Buy from Amazon


Schumacher Sc1319 1.5a 6v/12v Fully Automatic Battery Maintainer

Schumacher SC1319 1.5A 6/12V Fully Automatic Battery Maintainer

The Schumacher product is a no-frills, fully automated maintainer. If you want something that you can set and forget, this model is for you.

It’s designed with built-in programs for maintaining and charging. All you’ll be responsible for is plugging it in and connecting the clamps or ring terminals.

You won’t even have to press a button to select 12 or six volts. The Schumacher can automatically sense the voltage of the unit you connect it to.

The reverse polarity protection guarantees it won’t switch on unless it’s attached to the right terminals. There’s no need to be concerned about overcharging. It won’t work on defective units either. The display is in the form of LED lights. You’ll be able to see whether it’s charging or floating optimal charge (95 percent and above).

Features and Specifications

  • Suitable for six and 12-volt lead-acid batteries.
  • Single-battery maintainer.
  • Includes clamps, cord, and ring terminals.
  • LED light display.
  • Multi-stage precision programs.
  • Fully automated.
  • Spark-resistant; overcharge and reverse polarity protected.
  • Weight: 1.36 pounds.

What We Like

  • Fully automated.
  • Easy to set up and use.
  • Sensitive.
  • Long-lasting.

What We Don’t Like

  • LED indicators are basic.
  • Must disconnect battery cables beforehand.
  • Limited mounting/harnessing options.


If you want a tender that’s the epitome of “set it and forget it,” the Schumacher fully automatic battery maintainer may be right for you. The simple design and all-automated system require little human intervention to function.

Click this link if you want to buy one for yourself:


Click to Learn More / Buy from Amazon


Deltran Battery Tender 12-Volt 2-Bank Management System

Battery Tender 2-Bank Charger: 12V, 1.25 Amp Battery Charger with 2 Charging Banks - Smart Battery Charger and Maintainer Station Charges Up to 2 Powersport Batteries at Once - 022-0165-DL-WH

The Deltran 2-bank management system can work on 12-volt batteries, large and small. It can serve as a tender, charger, or both. This product is compatible with flooded, sealed, and maintenance-free lead-acid varieties.

The best aspect of the 2-bank design is that you can use it on two different units at once. If you have two vehicles that need maintaining at once, this product might work for you.

If you have a classic car in storage but need to recharge your daily ride, you can use the 2-bank for maintaining as well as charging the other battery. Anything that requires a 12-volt battery will be able to benefit from this unit too.

As with other Deltran models, this device is automated. It senses what mode to deliver power for—floating for maintenance, bulk, etc. The charge provided by this item is powerful. You’ll be able to get to 100 percent from nearly-dead faster than you expect.

Once you connect the power cord, there’s little left for you to do. Attaching it to power units of all sizes is easy, with included hardware plus harness. The LED lights will let you know what’s going on. The corresponding indications for each light setting are on the device itself, in case you forget the manual.

Features and Specifications

  • Amperage: 1.25 amps per bank (two banks).
  • Also available in four, five or 10-bank models.
  • Suitable for 12-volt batteries.
  • Compatible with lead-acid, flooded, sealed, AGM, and maintenance-free batteries.
  • LED display.
  • Spark-resistant and reverse polarity protected.
  • Dual-battery maintainer.
  • 2-year warranty.
  • Includes alligator clips, harness, ring terminals, and power cord.

What We Like

  • Temperature-resistant.
  • Wide range of applications.
  • Simple to set up.
  • Powerful charge.
  • Can be used on two power units simultaneously.
  • Compact.

What We Don’t Like

  • Short cable.
  • Can’t charge or maintain batteries of voltages beside 12 volts.


If you need to charge more than one 12-volt at a time, the Deltran 2-Bank is an optimal choice. As with other maintainers in this line, it’s simple to handle.

If this item sounds right for you, buy one here:


Click to Learn More / Buy from Amazon


Ctek Mus 4.3 12-Volt Fully Automatic 8 Step Battery Charger

CTEK (56-864) MUS4.3 12 Volt Fully Automatic 8 Step Battery Charger,Black

The CTEK MUS 4.3 is going to appeal to those of you who need a durable maintainer. This resistant device can run in temperatures from minus 4 to 122 degrees Fahrenheit.

It’s hardy in other ways too. The device itself is splash and dust resistant, which is great if your vehicle will be outside while it’s hooked up. CTEK maintainers are approved for

outdoor use year-round.

It’s equipped with an eight-step automated program. This enables the tender to diagnose, repair, and maintain as needed.

You’ll know immediately if there’s a problem. The second step of the program will evaluate whether or not your battery is defective. If it is, the gadget won’t deliver power to it.

You can modify the program if needed. There’s an option to create controlled gassing inside the power unit to mix the acid, which promotes energy, long term.

Ease of use is a standout benefit of the CTEK MUS 4.3 device. It’s designed with overcharge protection, to protect itself as well as your battery. Other safety features include being spark-resistant as well as reverse polarity protected.

The instruction manual provides clear, detailed instructions. You’ll also get in-depth information on how the device should be used to maintain and charge. Additionally, you’ll be able to see how long each stage of the program will take. A table is included in the guidelines for this purpose.

Features and Specifications

  • Amperage: 4.3 amps.
  • Suitable for all 12-volt lead acid batteries.
  • Spark-resistant; reverse polarity, overcharge, and short-circuit protected.
  • Water and dust resistant.
  • Eight-step program.
  • Cold-weather option.
  • Single-battery maintainer.
  • 5-year warranty.
  • Approved for year-round outdoor use.

What We Like

  • Detailed instruction manual.
  • Extra security features.
  • Can run in nearly any environment.
  • Excellent diagnostics.
  • Resilient to external damage.
  • Can be used outside.

What We Don’t Like

  • Accessories must be purchased separately.
  • Clamp wires are short.


This tough-tender from CTEK will fit the needs of vehicles kept in extreme conditions. The automated program is beneficial to the health of 12-volt lead acid batteries of all types.

If you’re thinking about making a purchase, follow this link:


Click to Learn More / Buy from Amazon


Mroinge Mbc055 6v/12v 5.5a Smart Vehicle Battery Charger

Mroinge MBC055 6V/12V 5.5A Smart Vehicle Battery Charger Maintainer for Cars Motorcycles RVs TVs Boat for Normal Lead Acid GEL AGM SEALED WET or 12V-Lithium(LiFePO4) Batteries, With IP65 Waterproof

This energy-saving product from Mroinge can maintain or charge more than one type of vehicle. It comes with a pair of clamps as well as terminal rings. You’ll like this gadget if you value precision in your automotive equipment. It is sensitive enough to gauge almost any change.

For example, let’s say you open your car door, and the interior light goes on. You’ll see the LED indicator light on the unit flash to indicate charging to replenish that small bit of power.

Another benefit is the four-step modes of operation. The initial soft-start program will determine the state of your power unit. If it’s severely depleted or discharged, a soft current will be delivered. This is to reduce the risk of damage until the voltage is high enough to sustain a normal charge.

The other three steps are bulk, absorption, and float. These ensure that you’ll get a full charge without overcharging. As an added measure, it has protection against short-circuiting. On the same note, this durable gadget has all the safety features you need. It’s temperature-resistant and waterproof to operate under different conditions.

Features and Specifications

  • Suitable for six and 12-volt lead-acid and lithium batteries.
  • Other models are available for other voltages and amperages.
  • Spark-resistant; reverse polarity, overcharge, and short-circuit protected.
  • Dual-battery maintainer.
  • Four modes of operation.
  • Temperature and dust-resistant.
  • LED light display.
  • Waterproof.
  • Energy-saving.
  • Includes harness, clamps, terminal rings, and power cord.
  • 2-year warranty.

What We Like

  • Lightweight
  • Hardware comes with purchase.
  • Sensitive.
  • Can repair discharges.
  • Simple-to-read LED display.
  • Built for safety.

What We Don’t Like

  • Less effective as a charger (takes a long time).
  • The clamps are smaller than average and not as easy to attach.


If you want a transportable maintainer that’s built for safety, this product from Mroinge may be the right selection for you. It’s also gentle on discharged batteries.

Check it out for yourself at this link:


Click to Learn More / Buy from Amazon


Ampeak 2/8/15a 12v Smart Battery Charger/Maintainer With Winter Mode

Ampeak 2/8/15A 12V Smart Battery Charger/Maintainer Automatic with Winter Mode

Those of you who appreciate technology will enjoy Ampeak’s 12-volt maintainer. This smart gadget is equipped with advanced diagnostics.

The six-step program compensates for batteries in a variety of states. The desulphation and soft-start modes can work on discharged or nearly-drained units. There’s little risk of overcharging or damage. The device will determine the optimal setting automatically.

It has a display screen for convenient usage. You’ll see the condition of your battery and what mode the device is operating on. This is practical for reducing or eliminating errors. With more basic LED light displays, it can be tricky to determine the source of the problem. The screen on the Ampeak will share in plain text what’s going on.

The most attractive aspect of the Ampeak device is flexibility. You can be involved as little or as much as you want in setting the programs up. For example, you can select the desired amperage—two, eight, or 15. Or, you can choose auto-mode and let the gadget do it for you.

If you’re storing your vehicle during the colder months, you can select winter mode. This tender can work in temperatures from 32 to 104 degrees Fahrenheit.

All this technology is shielded against potential failure. The product contains a cooling fan to prevent overheating. It also has protection against all the basics: reverse polarity, short circuits, and excess voltage.

Features and Specifications

  • Amperage: two, eight, or 15 amps.
  • Suitable for all 12-volt lead acid batteries.
  • Protected against over-voltage, over-heating, overcharging, reverse polarity, and short-circuiting.
  • Display screen.
  • Six-step charging program.
  • Single-battery maintainer.
  • Includes power cord and alligator clips.
  • Temperature-resistant.
  • 18-month warranty.

What We Like

  • Interactive monitor.
  • Intuitive diagnostics.
  • Winter mode.
  • Automatic programming.
  • Lightweight.
  • Thorough safety features.
  • Can repair discharged units.

What We Don’t Like

  • Vulnerable to the elements (e.g., condensation, dust, etc.)
  • Although it has a winter mode, it can’t be used at temperatures below freezing.


If you want a tender that’s both automated and programmable, you’ll want to think about this Ampeak model. The display screen is excellent for a user-friendly experience.

If you’re curious to see it in action, follow the link below:


Click to Learn More / Buy from Amazon


Optima Digital 400 12V Performance Maintainer and Charger

Optima Digital 400 12V Performance Maintainer and Battery Charger - 150-40000

The Optima Digital 400 has multiple settings to meet various needs. If you have a discharged battery you want to salvage, this gadget might be able to help. A distinct advantage is that there are separate modes for healthy and unhealthy (discharged) power units. This product is also adaptable to different types of vehicle.

In both standard and repair mode, you can customize the settings even further. You have the choice of picking motorcycle/power sport or auto/marine. There’s also a button for temperature compensation.

Despite all these options, this gadget isn’t a challenge to handle. The user interface includes a small display monitor, LED lights, and buttons.

Everything is labeled with easily-readable text. There are lights to inform you whether you need to check your power unit for a problem and when the tender is connected.

The user manual covers operation and function extensively. Even novices should be able to use this model without issue. Note, however, that the instructions state you shouldn’t connect it to 4D, 8D or other high capacity 6, 8 or 12-volt batteries, or lithium ion or dry cell batteries.

Features and Specifications

  • Suitable for all 12-volt lead-acid batteries.
  • Includes clamps, ring terminals, power cord, and wall mount.
  • Spark-resistant.
  • 3-year warranty.
  • Display monitor and LED lights.
    Spark-resistant; reverse polarity and overheat protected.
  • Six-step program.
  • Single-battery maintainer.

What We Like

  • Built-in hook for the hood of your vehicle.
  • Wall-mount for convenient storage.
  • Perfect for Optima batteries but also good for other makes.
  • Great user interface.
  • Can repair severely discharged batteries.
  • Explicit user manual.

What We Don’t Like

  • No power switch on the device.
  • Display monitor can fade over time.


The interactive interface of this product’s monitor is great for those of you who aren’t car-savvy. This maintainer is also optimal for users looking to save money by reviving near-dead six or 12-volt batteries.

If you want to buy one of these tenders for your automobile, click this link:


Click to Learn More / Buy from Amazon



A tender is a piece of equipment that almost anyone can benefit from. You don’t have to own a classic car or antique vehicle to use one.

It’s always convenient to have one of these devices around, to keep your vehicle’s battery in optimum condition when not in regular use. Most of them can be used for charging vehicles, too, and not just to maintain batteries outside of vehicles, which is useful for us all.

We hope with our help you’ve found the best battery maintainer for your needs. If you have any comments or questions, please do share your thoughts with us below. We’ll make sure to respond to all!


Product image credits: © Amazon.com

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From childhood go karting and motocross, to collecting and obsessing over scalextric, matchbox and radio controlled cars, I've always had an obsession with cars. Learning through manuals, books, trial and error, and more knowledgeable family members, I've also enjoyed tinkering with the mechanics and electronics of any vehicles I've owned. Now, over 3 decades later, I've started this site as a place for me to share my knowledge, to teach others how to care for and maintain their vehicles themselves, at home, so they can get the most of their vehicles and save a pretty penny compared to always seeking out professional help.

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