The best car battery chargers and battery maintainers

The pandemic lockdown of 2020 was a rude awakening for some car owners who didn’t have a portable jump starter or car battery charger in their garage. After not driving their vehicles for a few weeks or longer, they realized their car’s battery was dead and they had no easy way to get it going again. As expected, the market saw a huge jump in not only sales of portable jump starters, car battery chargers, and car battery maintainers, but also the number of companies manufacturing and selling those products. As a result, it has become difficult to pick out the good brands from the bad, and you don’t want a bad product being hooked up to your car’s battery.

There was a time when car battery chargers and car battery maintainers were two separate products. Battery chargers were designed to do just that: charge your car’s battery. Once it did its job, you would have to disconnect it because it served no other purpose. A car battery maintainer is what you would then use to make sure your car’s battery stays topped off over time, providing a charge only when voltage has dropped. Battery maintainers are best used when a vehicle is being parked for a long period of time and you don’t want the battery to die.

Nowadays, advancements in technology have allowed the functionalities of a car battery charger and a car battery maintainer to be combined into one convenient, portable product. Those are the products we’ll be focusing on in this article, and we recommend every car owner to have one in their garage. You simply never know when your car’s battery needs a charge, and we especially recommend one if you often store your car for winter.

1. Top pick: NOCO GENIUS10 fully automatic smart charger/maintainer

Our top pick comes from the same company that makes our best portable jump starter. Through the years, I have personally turned to NOCO’s products for their quality and reliability and the GENIUS10 is my preferred car battery charger and maintainer. This all-in-one product can serve as your battery charger and battery maintainer, as well as a battery desulfator. It’s compatible with 6- and 12-volt sealed lead-acid automotive, marine, RV, powersport, and deep-cycle batteries, fully capable of charging batteries as low as one volt, or you can attempt to use the “force mode” to take control and manually try to charge a battery that’s down to zero volts.

As a smart charger, it is equipped with an integrated digital thermal sensor, which automatically detects the ambient temperature and adjusts the charge so you don’t overcharge in hot weather or undercharge in cold temperatures. You can also use its battery repair mode, which is a slow pulse reconditioner technology that detects battery sulfation and acid stratification to restore lost battery performance.

This battery charger/maintainer is safe to keep plugged in all day long, for weeks or months. It’ll automatically maintain your car’s battery at a healthy charge. NOCO has a wide assortment of car battery-related products, so if this is a bit out of your budget, feel free to check out the rest of its lineup for something that is more affordable.

2. Runner-up: Battery Tender 4-amp car battery charger/maintainer

Our runner-up pick comes from another well-known brand in the battery industry, Battery Tender by Deltran. This brand is so popular, that some car owners mistaken “battery tender” as the product itself, much like “band-aid” for bandages. Like NOCO, Battery Tender has a huge lineup of offerings to cater to your car’s battery needs but for something that’s compact and easy to use, we recommend this 4-amp charger/maintainer. Once it fully charges your car’s battery, it will automatically switch to float mode and act as a maintainer, keeping proper voltage levels for your battery without overcharging.

With this battery charger and maintainer, you can easily switch from AGM or flooded and lithium-ion batteries, making it compatible for 6- and 12-volt batteries. This recommendation is ideal for car owners who want something simple and just works once it’s plugged in and connected. It’s spark-proof during lead connection and also has built-in reverse polarity detection before sending power. Battery Tender also provides an industry leading five-year warranty with its products.

3. Premium pick: Schumacher SC1281 fully automatic smart battery charger/maintainer

If you prefer to have a heavy-duty car battery charger/maintainer in your garage and aren’t necessarily a fan of smaller, more compact devices, take a look at Schumacher’s SC1281. It’s a full-featured smart battery charger and maintainer that has 30-amp quick boost and 100-amp jump starter, which makes it ideal for larger vehicles like a Porsche Cayenne. It offers up to 6 amps for charging and 2 amps as a maintainer.

The built-in auto-voltage detection means the charger will know whether you’ve connected a 6- or 12-volt battery to it, and it will automatically adjust the amperage rate for optimal charging. It also comes with advanced diagnostic features to help you troubleshoot issues with your battery or alternator.

4. Best on a budget: BLACK+DECKER BM3B fully automatic battery charger/maintainer

Not everyone needs or wants an advanced battery charger/maintainer. Some people prefer simplicity and knowing it just works. Others, well, they just want something more affordable because they won’t need to depend on it very often. If you’re one of these people and need something more for emergencies than general maintenance, consider BLACK+DECKER’s BM3B. It’s a basic and affordable battery charger/maintainer that is compatible with 6- and 12-volt batteries.

Like many of our recommendations, this little device will fully charge your car’s battery and then automatically switch to float mode to maintain that charge. The front display is pretty basic, with indicators for reverse polarity detection and whether your battery is fully charged. You will have to choose the battery voltage, as it won’t automatically detect it.

Despite its affordable price tag, this charger/maintainer is still packed with your standard safety features including built-in circuit protection to prevent overcharging, and it is ETL-certified for performance and safety. BLACK+DECKER also includes a mounting bracket so you can conveniently place this charger where you need it.

5. Honorable mention: HULKMAN Sigma 5 car battery charger/maintainer

Our final recommendation comes from HULKMAN, and although I haven’t personally tested this battery charger/maintainer yet, I have used the company’s portable jump starters with positive results. HULKMAN produces quality products so I have no reason to believe its battery charger/maintainer would cause you any issues. A total of five charging modes is offered on the Sigma 5, making it compatible with 99.9 percent of lead-acid batteries, including all types of 6- and 12-volt batteries, as well as lithium-ion batteries. It features a built-in sensor that detects the charging stage and ambient temperature, adjusting the charger as needed for those conditions.

It’s a bit of a high-tech option, with its 3.2-inch display in lieu of just indicator lights. The AI Smart Maintainer feature will automatically maintain your car’s optimal battery level and a 12-volt Force Charge mode lets you take full control to charge a battery as low as 0.3 volts.

It too has a battery sulfation and acid stratification detection feature, and it can be used to attempt to recover and repair your car battery. Safety features include high-temp, short-circuit, overcurrent, over-voltage, and reverse-polarity protection. The entire unit is IP67 rated, so it’s nice and durable.

What is a battery charger/maintainer?

As I mentioned in the introduction, there was a time where you had to purchase two separate products: one to charge your battery and one to maintain its charge. Now, you can purchase an all-in-one device that will first charge your car’s battery before switching to a float mode, topping off the battery when needed.

Who needs a battery charger/maintainer?

Everyone! And we’re not just saying that so you buy one. You never know when your car’s battery dies and sometimes you need more than just a portable jump starter. But for those who leave their cars parked for an extended period of time, you definitely want to keep the battery hooked up to a maintainer. This way, when it’s ready to be driven again, you don’t have to worry about charging the car’s battery.

Can I leave a charger/maintainer hooked up to my car’s battery for a long time?

If you purchased one of our recommendations, then yes. These devices are designed to fully charge your car’s battery and then maintain its charge for however long it’s attached to your battery. We do not recommend doing this with older battery chargers or trickle chargers as they aren’t designed for long-term use like these battery maintainers.

What are the differences between cheap and expensive battery chargers/maintainers?

The main difference besides quality and reliability is generally how long it takes the charger function to work. More affordable car battery chargers/maintainers tend to take a lot longer to fully charge your car’s battery. For some, that won’t matter.

What is maintain mode or float mode?

Many automatic battery chargers and maintainers use a feature called maintain mode or float mode. In this mode, the unit will keep your car’s battery charged by delivering small amounts of current when needed. If the unit detects that the voltage of the battery drops below a certain threshold, the charger will switch back to its charging mode. If your vehicle is being stored for a long period of time, a battery maintainer is the best way to ensure it starts up when you need it once again.

What is a trickle charger?

Trickle chargers aren’t the same as float chargers or some battery maintainers. The difference with trickle chargers is that they don’t have a sensor to check if a battery is fully charged. Instead, trickle chargers just continue to deliver current to the battery until it’s disconnected.

What is a manual battery charger?

Manual battery chargers are considered the simplest type of battery charger. You select a setting, hook it up to your car’s battery, and it’ll continue to provide that charge until you disconnect it. They don’t use any type of fancy sensors to determine the battery’s charge level. Nowadays, manual battery chargers aren’t recommended unless you are able to continuously keep an eye on the charging process. Once the battery is full, you’ll want to disconnect a manual charger, otherwise it could damage the battery.

Recent updates:

Updated (6:07 p.m. EST, 12/01/2022): Added a few more FAQs that explain the differences across battery chargers.