Battery Chargers vs. Battery Maintainers

While battery chargers and battery maintainers are both helpful tools for vehicle owners meant to help keep your battery charged, they do have a few significant differences that make these tools stand on their own. A battery charger is typically used when your battery needs a significant charge, or a complete recharge. A battery maintainer is different from a battery charger in that it’s designed to supply your battery with a small amount of charge for long periods of inactivity. Both tools are designed to charge and extend your automotive battery’s life, and some battery chargers may also feature a maintainer feature to allow them to operate using either charging method. Keep reading to learn more about the differences between battery chargers and battery maintainers, as well as a few helpful product tips.

O'Reilly employee working on a vehicle with the hood up

The main difference between a battery charger and a battery maintainer is that a charger applies a constant charge until the battery is fully recharged, which means it needs to be disconnected once the battery’s charge is replenished. This means that some older battery chargers cannot be left connected and unattended for long periods, though most modern battery chargers are equipped with a maintenance feature to help prevent overcharging. Jump-starting your car and forcing the alternator to restore battery charge can take 30 minutes or more, and may cause excess stress on the alternator, leading to premature failure. If your vehicle's battery has sufficiently drained, it’s recommended to recharge it using a battery charger whenever possible.

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A battery maintainer, on the other hand, will charge only when the voltage of the battery has dropped below a specific level, so it can be left connected and unattended for much longer periods. This makes battery maintainers particularly useful for storing vehicles or batteries over extended lengths of time. While both tools are designed to charge your car battery, a battery charger is ideal for substantial recharges while a battery maintainer can be used to increase your car battery’s lifespan when the battery or vehicle aren’t being used for extended periods of time. This can also be applied to vehicles like lawn tractors or lawn mowers, ATVs and UTVs, or other applications that might require seasonal or longer-term storage to prevent the battery from discharging and failing over time.

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Schumacher Battery Maintainer

The Schumacher Battery Maintainer is the perfect solution for someone looking to maintain 12-volt batteries. With a charging rating of 8/10 of an amp, it can provide steady current for overnight battery charging OR longer-term battery maintenance.

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Schumacher 12-Volt Battery Maintainer

The next option is a higher-performance Schumacher 12-volt maintainer with a 3-amp output, so it will restore battery charge levels much faster. This maintainer can be used for both 6-volt AND 12-volt batteries, as well as AGM batteries. This battery maintainer offers a great, versatile choice if you’re dealing with different battery types.

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Schumacher Bank Maintainer

If you have more than one battery to maintain, we also have multi-bank maintainers like this Schumacher Bank Charger. This 2-amp maintainer has 2 banks, and is also capable of handling both 6- and 12-volt batteries and AGM batteries.

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When it comes time to make a purchase, the first thing to determine is whether your battery and charging system is set up for 6-volt or 12-volt power. Most vehicles run on 12-volt batteries. However, you can still find 6-volt systems and batteries in older cars, some motorcycles, lawn equipment, and golf carts. If you have a 6-volt battery, be sure only to use a 6-volt maintainer. Applying too much voltage can cause damage to the battery. When purchasing a battery charger or maintainer, you’ll also need to consider whether your battery is a standard or AGM, or absorbed glass mat, battery. If you use a standard battery charger or maintainer on an AGM battery, damage can occur that may shorten the battery’s lifespan. Lastly, the amperage of the battery charger or maintainer is also an important factor to consider. The amperage of a battery charger will determine how quickly a battery is charged: The higher the charger amperage, the more quickly it will recharge a car battery.

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When you store a vehicle for long stretches—for example, over the winter months—whether that’s a boat, motorcycle, lawn mower, ATV, or classic car, its battery can discharge through the electrical system. The longer a battery is discharged or the longer your vehicle sits without running, the less likely the battery is to start the vehicle again when the time comes. A battery maintainer can not only help keep the battery charged, but keeping consistent charge supplied to the battery can help extend its life.

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Battery maintainer being connected for a long period of time.

Battery maintainers are also designed to be completely automatic, so you can leave them connected for long periods of time. They use a system that applies the appropriate amount of current based on the charge level of the battery. When the battery is fully charged, the maintainer will switch over to float mode to maintain the battery at full charge. That means the battery maintainer will only charge the battery when it drops below a certain voltage, and never more than necessary.

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If your car battery isn’t charging, or if it is losing charge quickly or turning your engine over slowly, bring your battery into your local O’Reilly Auto Parts store and have your car battery tested for free. We also offer free battery charging if you can’t charge or jump-start your vehicle’s battery at home. While you’re there, our parts professionals can help you find the batteries, battery chargers, battery maintainers, and other battery tools you need to keep your car running its best.

The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.

Battery Chargers and Battery Maintainers