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What is a Battery Maintainer?

A parked car sits in storage that will need a battery maintainer.

If you plan to leave your car parked and out of use for long periods, it’s important to give some thought to the health of the vehicle’s battery. Leaving your vehicle inactive for an extended stretch of time could cause the battery to lose its charge, but a battery maintainer can prevent this from happening.

What is a battery maintainer? It’s a device that can deliver the right amount of charge to your vehicle’s battery to keep it charged when it’s not being used regularly. Here we’ll take a closer look at these devices and how to select the right type for your vehicle.

What Causes a Parked Car’s Battery to Drain?

Your car may have been sitting parked for weeks, but that doesn’t mean its battery hasn’t been in use during that time. Even when your car is parked, the battery is powering your vehicle’s alarm system, computer systems and other electrical features. All of this can slowly drain power from your vehicle’s battery if the car isn’t being driven enough to recharge on its own.

Another factor that can cause the battery of a parked car to lose its juice is temperature. If you live in extremely hot weather, the heat of your surroundings can drain your car’s battery while it’s parked. At the other temperature extreme, very cold weather can also be taxing on batteries — the chemical reaction that generates electricity slows, yielding less power, and oil becomes thicker, which means more power is needed to get the engine started. Even in ideal temperatures, batteries slowly discharge, so it’s important to use your vehicle regularly to keep it with raised hood

Your car’s alternator is essentially a generator for your vehicle’s electrical system that’s responsible for recharging the battery. However, it’s mechanically powered, so it only kicks in when the engine is running. If the car is parked for long periods, the alternator won’t have a chance to do its job, and it becomes much easier for your car’s battery to lose power.

Battery Maintainer Basics

So, what is a battery maintainer? This tool dispenses small increments of electricity to the battery over time while the car is inactive, ensuring that the battery always has enough charge to power the vehicle’s systems.

In some respects, a battery maintainer is similar to a battery charger. But the two products differ in key ways. A battery charger delivers a steady flow of electricity until the car battery is fully charged, and once charging is complete, it needs to be disconnected.

A battery maintainer, on the other hand, monitors the charge, delivering more only when the battery’s voltage drops. Because of this, a battery maintainer can be left unattended while it’s connected to a vehicle for a long period of time, which isn’t the case with a standard battery charger.

How to Choose a Battery Maintainer

It’s important to choose a battery maintainer that will provide the right amount of voltage for your car’s battery. Most cars use 12-volt batteries. If this is the case for your vehicle, you’ll need a 12-volt battery maintainer.

Still, there are some older cars that use 6-volt batteries. This type of battery is also used by golf carts and RVs, so if you have one of these vehicles, it’s essential to use a 6-volt battery maintainer. Using a battery maintainer with too much voltage can damage your battery.

You’ll also need to consider whether you have a standard or absorbed glass mat (AGM) battery, as the two types may require different battery maintainers. The packaging for the battery maintainer should let you know whether the product is compatible with your battery.

If you leave your car parked over the winter or during a long vacation without taking proper precautions, you could return to a dead car battery. Avoid this frustration and look into picking up a maintainer today.

Check out all the batteries and battery accessories available on NAPA Online, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on choosing a battery maintainer, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.


Warren Clarke View All

I'm a writer and editor who's a regular contributor with the New York Daily News and Carfax, and my content has appeared in over 20 publications. I've written content that covers industries such as automotive, medical, insurance, healthcare, real estate, plumbing, pest control, dental and hospitality.

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