Battery Boosters and Chargers Guide

Battery chargers, maintainers, and boosters all perform slightly different functions, but all of them make fantastic gifts for holidays, or any season. Below, we break down the advantages and features of each:

Battery Chargers vs. Maintainers vs. Jump Starters

1. Battery Chargers

Battery chargers have come a long way from the old days of hooking up the clamps, plugging it in, and attempting to look at an old, analog gauge to understand whether or not the battery is charged. Today, battery chargers all use digital technology to sense charge, detect problems with bad batteries, reversed cables, and provide a safe, effective charge to the battery. On top of that, they let you know once the charge is complete, taking away the guesswork of the old days. An example of a charger using these features is the Duralast DL-75D, available in AutoZone stores.

When shopping for a battery charger, it’s important to understand several of the other functions that chargers can provide. Most chargers on the market provide 3 charging functions – a low amp, or trickle charge (which is generally 1 to 2 amps), a standard charge (generally 6 to 10 amps), and an engine starter, which is essentially a boost of 75 to 100 amps. Several other chargers also have a feature of a “maintain charge”. Let’s go through what each of these various charging cycles actually mean.

Low Amp/Trickle Charge: A trickle charge often is the most effective way of charging a battery. It’s very slow, steady, and often takes 1-2 days to properly charge the battery. It does so by providing a very low amperage. Trickle charging is what is also used in Battery Maintainers, which we will talk about their use and importance later.

Standard Charge: A standard charge allows you to charge a battery – in most cases – in 3-5 hours, sometimes sooner. Every battery, based on it’s use and age, responds differently to charging, but most people use a standard charge because they need use out of the battery as soon as possible.

Boost or Engine Starting: The Engine Starting Feature of a battery charger is designed to supply a strong current of 75-100 amps to help start a vehicle if the battery is charged enough to turn the engine over, but not enough to turn it with the speed needed to start the engine. This supplied boost generally only lasts 30-60 seconds before the charger shuts off the current. It’s important to note that this feature is different than that of a separate Battery Booster (discussed below), which supplies a much higher amperage boost and can start a car with a completely dead battery.

2. Battery Maintainers

One of the big killers of batteries is a series of constant discharges / recharges. A battery can only take so many of these before it simply loses its ability to take and maintain a charge. Many times, items that suffer from this are lawn and power sports equipment, or vehicles that are rarely driven or stored for the winter – anything that goes a long time in between use. Because of this, battery maintainers are a fantastic item to solve this problem.

A battery maintainer is essentially a very small version of a battery charger that serves one purpose – supply a very low-amperage trickle charge to the battery only when it needs it, and in that sense, keep it “maintained” at the proper voltage at all times. Maintainers are generally the size of the palm of your hand, and provide 2 types of ways to connect to a battery. You can use standard “alligator” clamps like all chargers use, or you can go with a permanent solution that allows you to wire a pigtail connector right into your battery cables. This way, when you want to hook the maintainer up, you simply plug the connector in, plug the maintainer in to the wall, and you are ready to go.

Maintainers are growing in popularity as customers realize that replacing a $100.00 battery every year, or 2 years on multiple pieces of equipment is far worse than buying a $30-50.00 maintainer to keep all your batteries in top shape when not being used. Many maintainers have multiple circuits, so you can maintain multiple batteries at once (think of boats that may contain 2-3 batteries), or, buy a maintainer for every piece of equipment you have that uses a battery. One such maintainer is the Duralast DL-2D.

Keep in mind, that many Battery Chargers also have a “maintainer” function, as discussed before. This means that when the battery is kept hooked up to the charger, the charger will sense if the battery drops below the ideal threshold of a charge, and will then subsequently charge the battery. While this is a great feature to have, it only works for one battery, whereas the smaller, cheaper maintainers can be purchased for multiple batteries. More recent technology has seen Solar Maintainers come on the market, which is also a great solution if getting power to the location of the batteries is an issue. A solar maintainer can be kept on a car parked in a driveway, or equipment inside a shed with no power, as long as the solar panel can be placed outside in the sun.

3. Battery Boosters

Battery Boosters, or Booster-packs are essentially a portable car battery. They provide high amperage (800-1200 amps) power through connector clamps, and can start a vehicle with or without a battery. Most standard jump packs are about a cubic foot in size, have a carry handle, and many can be rather heavy as they are housing a heavy duty battery. An example of this is the Duralast DL-1200AC, which is a Jump-starter and an emergency air compressor all in one. These boosters are a great addition to any garage or shop, making it much easier than the, “honey, can you pull the car around to the truck and get the jumper cables!” approach to starting something with a dead battery.

Over the past few years, Lithium Ion Boosters have risen rapidly in popularity. They are small in size, lightweight, and provide a ton of starting power, while at the same time, providing this in a small package that can easily be stowed in a Car, Truck, or Boat for emergency use. We run one of these Lithium Ion boosters, the Duralast DL-800L through the paces to show just how powerful it really is.

It’s important to note that starting a vehicle with a very-dead battery is not a best-practice and should be left to emergencies only. A modern-day alternator is not designed to completely charge a dead battery that could not start a car – it’s designed to provide power to a car that is already started, and maintain the battery’s constant charge, which is much easier than charging a battery that’s dead. It will, and can, but can be super taxing to an alternator, and many times, lead to failure. This is why many times, customers who come in for a battery replacement who have repeatedly jump-started the car over weeks and weeks suddenly find that their alternator is now not working either. When ever possible, always charge a battery properly first – if you have time.

Advice, how-to guides, and car care information featured on and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

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