Written By
Published Sep. 29, 2021

You might think your engine breathes life into your car but, without a good battery, you’re not going anywhere. The problem is the vehicles that give us the most enjoyment are often the ones we get to take out the least. And when you finally get a chance to turn the key in your favorite vehicle, the last response you want is a strained churn or, worse, rapid clicking noise. Thankfully, you can hook up a battery maintainer to your motorcycle or classic car to keep their battery healthy year-round. These devices can even restore batteries that are essentially dead, giving them a few more years of life. Below is a battery maintainer buying guide and a list of all the top products in the niche.

Best Battery Maintainers Reviews & Recommendations

Best Overall

The Noco Genius1 is designed to perform the duty of a battery maintainer exceptionally well, while not breaking the bank. This model delivers a 1-amp charging current, making it 35 percent more powerful than the previous Noco G750. It’s also 35 percent smaller than the G750, measuring 3.43 x 4.02 x 6.73 inches. Since it weighs just 0.95 pounds, it’s extremely portable. This is one of the most diverse models on the market, with the capacity to charge 6-volt and 12-volt lead-acid automotive, deep-cycle, gel, AGM, and lithium-ion batteries. An integrated thermal sensor ensures that this device won’t overcharge in hot climates or undercharge when it’s cold.

There’s a nine-step charging sequence, which is as follows: analyze, diagnose, recovery, initialize, opportunity, bulk, absorption, optimization, maintenance. During the recovery stage, it starts the desulfation process for deeply discharged or sulfated batteries, if needed. You can safely leave this model plugged in and charging year-round, as its zero-overcharge feature ensures it’ll stop charging your battery when it’s full. The Genius1 will automatically charge batteries as low as 1-volt, or you can manually use the new Force mode to charge a completely dead battery.

Specs
  • Brand Noco
  • Model Genius1
  • Weight 12.3 ounces
PROS

IP65 rating

35 percent smaller and more powerful than the previous version

Force mode

Suitable for all battery types

Nine-stage charging sequence

CONS

1-amp current won’t recharge a low battery quickly

Anyone who’s looking for a simple, cost-effective battery maintainer should consider the Motorpower 12V 800mA Automatic Battery Charger. This is one of the lowest cost products on the market and designed for anyone who knows they won’t be able to maintain their battery for a while. It’s suitable for all 12-volt lead-acid, flooded or sealed, and maintenance-free batteries (AGM and gel-cell).

This model detects if your battery has a sulfation problem and repairs it using pulse current technology. Once you connect this maintainer, it will run through five charging stages including diagnosis, soft start, bulk charge, absorption, and float/maintenance. During the five-stage process, it removes troublesome crystals and absorbs them into the charging cycle, increasing your battery’s lifespan. The downside to this model is that it’s only rated at 800mA, so if you’re trying to breathe life into a battery that’s almost completely dead, it’s going to take a while.

Specs
  • Brand Motopower
  • Model MP00205A
  • Weight 11.7 ounces
PROS

Excellent value for money

Five-stage charging sequence

Suitable for all 12-volt lead-acid, flooded or sealed, and maintenance-free batteries

CONS

Low current of 800mA

Not a great long-term maintainer

Not suitable for 6V batteries

Premium Pick

The Noco Genius10 is one of the most diverse battery maintainers on the market, thanks to its power, portability, and adaptability. It’s similar to the old G7200, except it’s 17 percent smaller and 115 percent more powerful. This model has a 10-amp charging current, making it one of the most powerful on the market, so it’s a great option for anyone who needs to charge their battery relatively quickly. It measures 4.41 x 4.48 x 9.1 inches and weighs just 3.33 pounds. Unfortunately, running so much power through such a small charger drives the price up considerably, which is its only real negative point.

You can use this model on 6-volt and 12-volt lead-acid automotive, marine, deep-cycle, and maintenance-free batteries. It’ll automatically recharge batteries that are as low as one volt. But if a battery is completely dead, then you can use the Force mode to manually bring it back to life. This model can accurately charge your batteries in temperatures as low as minus 4 degrees Fahrenheit to 104 degrees Celsius thanks to its in-built thermal sensor. Thankfully, it’s IP65 rated, so you can rest assured that it’s built to last and spark-proof technology and reverse-polarity protection, keep you and your battery safe during the connection process.

Specs
  • Brand Noco
  • Model Genius10
  • Weight 3.3 pounds
PROS

10-amp current

IP65 rating

17 percent smaller and 115 percent more powerful than the previous generation

Nine-stage charging sequence

Suitable for all battery types

CONS

High price point

No boost function found on some other high-end maintainers

The 2/10/25A 12V Smart Battery Charger/Maintainer can handle practically any 12V battery maintenance task. You can set it to one of three modes: 2-amp trickle charger, 10-amp quick charge, and 25-amp boost charge. This is the most powerful maintainer on this list by a large margin. If you use the 25-amp setting, this model can charge most batteries to around 80 percent in just two minutes flat.

One of this maintainer’s stand-out features is its seven-step charging program: desulphation, soft start, bulk charge, absorption, battery test, reconditioning, floating. It can charge all types of 12V lead-acid batteries, including gel, AGM, and STD. Unfortunately, you won’t be able to charge 6V batteries with this model and this is easily the heaviest and bulkiest unit on this list but, on the upside, its hard ABS shell is highly protective and impact-resistant.

Specs
  • Brand TowerTop
  • Model TP108MB
  • Weight 5.26 pounds
PROS

Can charge a battery with sufficient power in 120 seconds

Seven-stage charging sequence

Charging current up to 25 amps

Three maintenance/charging modes

CONS

Bulky

Relatively heavy

Higher-end of the price range

Pick up the Battery Tender Junior 12V, and you shouldn’t need to buy another maintainer for years to come. This model has an industry-leading five-year manufacturer’s warranty and it’s suitable for all lead-acid and lithium-ion 12V batteries, although you can use it with an AGM battery, it might reduce the battery’s lifespan. If you need a maintainer for an AGM battery, then check out the ‘Plus’ version of this model.

Once you connect this maintainer, you can forget about it as it automatically manages your battery’s health. This model is rated at 800mA, so it’s not going to charge any automotive battery in a hurry. There’s an ISM microcontroller that constantly updates the charge sequence depending on what your battery requires at any given moment. The four-stage charging sequence is as follows: initialization, bulk charge, absorption mode, and float/maintenance mode. You’ll never need to worry when connecting this maintainer, as it has reverse hook-up protection.

Specs
  • Brand Deltran USA LLC
  • Model 022-0199-DL-WH
  • Weight 1.17 pounds
PROS

Renowned for its reliability

Five-year manufacturer warranty

Recovery stage

CONS

Not the best option for AGM batteries

Low 800mA current

How We Selected Battery Maintainers

We considered dozens of battery maintainers before choosing our top contenders. Some brands are already well-established in this niche, and priority was given to their products provided they had positive user feedback. Other lesser-known brands were also evaluated as long as there were a sufficient amount of owner testimonials. The main features taken into consideration were amperage, durability, reliability, price, safety features, charging sequences/modes, and portability. We avoided products that had multiple reports of malfunctions, which caused damage to the connected battery. 

Our product selections, rankings, and awards for this story are based on research. While we haven’t conducted real-world testing on all of these products yet, we’ve looked at consumer testimonials and data, tutorials, and general discussions on social media and in forums. We also consider price and specification in the context of the segment. And, of course, we rely on our institutional knowledge of the automotive landscape to weed out weak products.

Buying Guide/What to Look For 

Battery maintainers all perform the same basic function. So, why do they vary in price so much? The main differentiator is how much current the maintainers can process. Some models have extra features, which can quickly get you out of a sticky situation. There’s also a notable improvement in reliability and durability when you use a maintainer made from high-quality materials. 

This guide will explain the different battery maintainer features and types to look out for. So you can decide what ones you need and avoid paying for anything unnecessary. 

What to Consider When Buying A Battery Maintainer

Types of Battery Maintainers

Single Bank

Single bank battery maintainers are extremely common and they’re designed to maintain a single battery at any one time. These maintainers are more affordably priced than their counterparts and the most economic option if you only intend to maintain one battery. 

Multiple Bank

Multiple bank battery maintainers can maintain up to 10 batteries at once. These types are more common in commercial settings, but they’re useful for people who have a few automobiles that you don’t drive very often. The only downside to these battery maintainers is that they’re more expensive than single bank models. 

Hybrid Maintainers

Hybrid battery maintainers do more than just keep your battery topped up. These devices work as battery boosters as well as maintainers, so if your battery is low before hooking it up to a hybrid maintainer, it’ll be restored to full power. These maintainers can also restore batteries that are damaged. Although the maintainer can’t restore batteries to their original health, their lifespan will increase notably.

Battery Maintainer Key Features

Amperage

The amperage is the measure of current that runs through a battery maintainer. In essence, this is how powerful the maintainer is. Some maintainers will be as low as 800mA, and others can be up to 25 amps. Bigger isn’t necessarily better, as maintainers are designed to be used over long periods. So a low amperage maintainer should perform just as well as a high-current model over months of use. 

The only benefit of getting a high-amperage maintainer is that it can charge your battery quickly. Some of these chargers/maintainers can get your battery up to around 80 percent in 120 seconds. But you’ll pay for all these extra amps, so choose a model with an amperage that’ll suit your needs.

Safety Features

The beauty of a battery maintainer is that you can plug it in and forget about it. The device’s built-in safety features are what allow us to leave it running with peace of mind. The most important feature is arguably short-circuiting protection, as a short-circuit could cause the maintainer to explode. But you should also look out for voltage protection, which stops and adjusts the maintenance process if the battery’s voltage is too high for the charge mode.

Another feature we recommend having is reverse polarity protection. So, if you accidentally connect the clamps in reverse order, the maintainer will cut the power instantly. All maintainers should have an overcharge safety feature, which stops them from continuing to charge your battery when it’s full.

Charging Sequence

Battery maintainers have a charging sequence designed to charge and maintain your battery in a safe, effective manner. The most common charging sequence is as follows: Initialization, bulk charge, absorption mode, and float/maintenance mode. However, some premium battery maintainers have charging sequences that consist of up to nine stages.

Extra charging sequences can help keep your battery in better condition. For example, some maintainers have a ‘recondition’ or ‘recovery’ stage, which is a unique charge state to recover deeply discharged or sulfated batteries. If you use expensive batteries, it could be worth investing in a maintainer with extra protective sequences.

Durability

A battery maintainer is designed to be left alone, not requiring any maintenance from you. But if you live in a climate that changes from damp and cold to hot and dry throughout the year, it can take its toll on the device. Ideally, you’d get a battery maintainer with weather protection, so you don’t need to worry about it getting damp over winter. The best weather protection you’re likely to find is an IP65 rating, so look for that. A device with this rating will be water-repellent, but you should never soak it entirely. 

Reliability

If you buy an unreliable maintainer, the best-case scenario is that the device breaks. The worst-case scenario is that it destroys your battery and damages your vehicle’s engine bay. Before choosing a battery maintainer, check out user reviews and look for any trending reliability issues. The length of a manufacturer’s warranty can also indicate how reliable the product might be. 

FAQs

Q: Is it OK to leave a battery maintainer on all the time?

Yes, this is what these devices are designed to do. A maintainer won’t overcharge your battery as it will stop charging once the battery is full.

Q: What’s the difference between a battery charger and a maintainer?

A battery charger will apply a constant charge to your battery, even after it’s full. For this reason, you can’t leave a battery charger connected and unattended for extended periods. A battery maintainer will stop charging your battery once it’s full.

Q: When should I use a battery maintainer?

Use a battery maintainer when you have a battery that won’t be used for long periods. 

Final Thoughts

We’ve chosen the Noco Genius1 as our best overall battery maintainer. This product is one of the most reliable and durable maintainers on the market and also won’t break the bank. But if you’re on a really tight budget, then check out the Motorpower 12V 800mA Automatic Battery Charger. This model will perform the basic needs you need to keep your battery alive through the off-season.

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