What is a vehicle battery charger? It charges car batteries, right? How complicated can it be? Believe it or not, there are literally hundreds of models of chargers to fill every situation. What’s your situation? Your particular situation will determine which vehicle battery charger you will choose for your car.


Vehicle Battery Charger: NOCO Genius G3500 Smart Battery Charger Under Hood ViewVehicle Battery Charger or Jump Starter?

The first question to ask is if you actually need a vehicle battery charger at all or are just looking for an emergency jump starter to carry in your car. Battery chargers typically stay at home in the garage or shop and are plugged into household current in order to charge a battery, and in many cases, maintain its charge as well. Jump Starters are really portable batteries with built-in jumper cables that you can carry with you in your car and in an emergency, use to jump start your low car battery. If you’re looking for a jump starter, this article is not for you. I will write another article on how to choose a jump starter.


Interested in seeing 12V battery charger choices?  Be sure to see our other articles about some of the best!


Battery Size and Voltage

Next you need to ask yourself, in what vehicle will the battery be used; a car, boat, light truck, garden tractor, classic car, etc.? The vehicle will determine whether the device will need to charge a large battery or a small one and if it needs to handle only 12 Volts or will need to also handle 6-Volt applications. A common inexpensive car battery charger for home use can typically accommodate 12-volt batteries and in some cases, will handle 6-volt batteries as well. If you don’t have a need for 6 Volts (some classic cars and some tractor batteries), and don’t think you ever will, then you can save money if you choose a 12 Volt vehicle battery charger. These days, some of the best home chargers are still relatively inexpensive and will handle both 6- and 12-Volt applications.

Vehicle Battery Charger: Schumacher SP-1 Full ViewBattery Chemistry

And you thought you left chemistry behind at school… I promise I will make it simple! Most all car batteries are lead-acid batteries with lead plates in an acid bath. Where they differ in chemistry is whether they are standard lead-acid, AGM, Gel Cel, or Deep Cycle. You don’t need to know what those chemistries mean, you just need to know which type they are. Not all chargers are designed to handle the special needs of AGM, Gel Cel or Deep Cycle types. Most are standard lead-acid. The specialty types can be found in applications designed for other equipment besides cars.

Fully Automatic

Battery chargers can be manual or automatic. Many are fully automatic which means they can detect when your vehicle’s battery is fully charged and automatically switch to a maintenance charge or float mode to protect it from overcharging. This is an important feature that is available on many better-quality vehicle battery chargers.






Safety First

There are many safety features available on modern car battery chargers and the more you have, the better. Some safety features to look for include:

1) Vehicle Battery Charger Reverse Polarity Warning

An auto battery charger can warn you if you have the wrong cable hooked up to the wrong post and in many cases, prevent dangerous sparking. Without this protection, reversing polarity can cause sparking which could ignite gas around the battery and cause an explosion.

Vehicle Battery Charger: Eco-Worthy 100W Foldable Solar Suitcase2) Float Mode

A fully automatic charger will have a float or maintenance mode which detects when it is fully charged and backs off the primary charging process step so as not to harm the battery from overcharging. In some cases, severe overcharging can cause overheating, damage or even explosions.

3) Spark Proof Clamps

No matter how careful you are sparking is still possible when connecting the charger clamps of a 12V battery charger.  Some devices have a safety feature that reduces or even prevents sparking at the connection.

4) Battery Tester

Some chargers can detect the health of your battery. Over time lead-acid batteries can build up sulfate on their plates reducing their ability to accept a full charge. Some devices can detect that it is unable to accept a full charge and alert you to the problem or even attempt to correct it.

5) Battery Tending/Maintenance

Many chargers can provide maintenance or tending for your battery while connected. This is especially useful for those vehicles with batteries which are only used rarely or are in storage for part of the time like garden tractors, motorcycles, boats, RVs, classic cars, etc.

Vehicle Battery Charger: Optimate 6 Ampmatic TM-181 Charger Maintainer6) Clamp Amps

Clamps that connect to the posts have an amp rating. Usually that rating is 50 amps or more. It should not be less.


That’s right, you can even buy a vehicle battery charger that gets its power from the sun.  A solar car battery charger will generally do a better job as a battery maintainer than as a battery charger. That’s because the amperage of solar car battery chargers is so low.  That said, if you’re going to be off the grid for any period and need to keep a vehicle battery charged, a solar charger is one option.

Other Desirable Features

1) Microprocessor Control

Basically a microprocessor is a computer on a chip that can direct the entire charging process based on feedback from the 12 volt battery charger and the battery itself. Many modern chargers are microprocessor-controlled and those that are have more options for conditioning or recovering batteries and have much finer control over the charging process, even improving charging performance.

2) Multi-Step Charging

Some chargers have the capability to charge in multiple steps which gives them the flexibility to more finely control the charging process. Steps can range from just charging and float modes to as many as 7 steps as provided by, for example, NOCO Genius Chargers:

Vehicle Battery Charger: CTEK 56-864 MUS 4.3 12V Automatic Charger MaintainerStep 1: Diagnostics
Checks the voltage to make sure connections are good and the battery is in a stable condition before beginning the charge process.

Step 2: Recovery
Initializes the Recovery process, if needed, for deeply discharged or sulfated (desulfation) batteries by pulsing small amounts of current.

Step 3: Soft Start
Begins Bulk charging process with a gentle (soft) charge.

Step 4: Bulk
The Bulk charging process continues and returns 80% of the battery capacity. Indicated by the 25%, 50% and 75% CHARGE LEDs.

Step 5: Absorption
Brings the charge level to 90%. The charger will deliver small amounts of current to provide a safe, efficient charge and limit gassing.

Step 6: Trickle
The battery is fully charged and ready to use. In this step, the charger will only deliver enough current as it is required. If more current is needed, the charger will switch to Maintenance.

Vehicle Battery Charger: Solar Array ViewStep 7: Maintenance
Continuously monitors the voltage to determine if a maintenance charge should be initiated. If the terminal voltage falls below a specific value, the charger will start the Maintenance cycle until voltage reaches the proper value and then discontinues the charge cycle. The cycle between Trickle and Maintenance is repeated indefinitely to keep a full charge, without overcharging. The charger can be left connected indefinitely.

3) Multiple or Appropriate Charging Amp Rates

Many chargers will either have multiple charging amp rates depending on whether you are charging a small battery, a large one, or you are maintaining or tending one. It’s common to see at least 2-amp and 10-amp charging rates if not a medium 4-6 amp rate as well. It’s not critical to have large charging amp rates unless charging time is important to you. A microprocessor controlled battery charger with a lower amp rate will charge more slowly but, if the duration is not unacceptable, will do the job. Check the battery charger to make sure it matches your application as far as charge time and charging amps.

4) Ease of Use

If it’s important to you that a charger is easy to use then fully automatic with minimal adjustment is the way to go. If you have more than one battery and each is a different type, then you may need a little more complicated setup and a more capable charger with selections for output voltage, charging rate, battery chemistry, etc. Chargers can be heavy or light, large or small, bulky or easy to carry. Look for handles on bigger chargers if you need it to be more portable.





Vehicle Battery Charger



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There you have it. In this article, I have covered many of the features and specifications that you should consider when choosing a car battery charger. A great place to look for a charger is on Amazon.com where you can compare the features of their most popular models and read the reviews of each vehicle battery charger by owners who already made their choice.