How to Charge a Car Battery

Want to learn how to charge a car battery to maintain or restore it? This article reviews the different methods and devices you can use to maintain or recharge a car battery.

How to Maintain and Charge a Battery in Your Car, Truck, or SUV

Different Tools and Ways to Maintain and Charge a Car Battery

1A Auto expert mechanic Len breaks down battery chargers into three main categories.

1. Maintainers

Maintainers provide a low current charge.

There are different types of maintainers

  1. Solar-powered battery maintainers
  2. Electrical battery maintainers

Solar-Powered Battery Maintainers

Solar-powered battery maintainers are powered by sunlight. They can sit on areas like the windshield or they can plug into the auxiliary port and charge from the dash as long as there is sunlight and the vehicle has constant power (meaning the vehicle has power whether the car is on or off).

How to Use a Solar-Powered Battery Charger

Steps for how to charge a car battery with a solar-powered charger

  1. Decide if you want to put the charger inside or outside the car

    If you want to place the charger outside of your car, skip to step 3. If you want to put the solar-powered charger inside your car, go to the next step.

  2. Find out if your vehicle is keypowered or has constant power

    Vehicles with constant power have power even if the car is off.

    Vehicles that are keypowered only have power if the key is in the on position or if the vehicle is on.

    To find out if your car or truck is keypowered or has constant power, plug a device like a phone charger into the auxiliary port. If the charger works when the car is off, the car has constant power. If the charger only works when the key is in the on position, it is keypowered.

  3. Attach the solar-powered device to the battery

    Attach the clamps to the terminal and place the charger in an area that has sunlight, like on the windshield.

    If you want to put the charger inside your car, go to the next step.

  4. Attach the solar-powered device to the auxiliary port

    If the car has constant power, plug the charger into an auxiliary port and place it in an area that has sunlight like the dash.

    Note: Dirty and tinted windows can reduce the charger’s capabilities. If the charger is not in direct sunlight, it will not have full charging capability.

    It is also not a good idea to leave a device like a phone charger plugged in for days if you have constant power, because it is pulling a draw on the battery.

Electrical Battery Maintainers

Electrical Battery Maintainer

Electrical battery maintainers are simple. They plug in to an electrical outlet and attach to the battery terminals with clamps.

This category trickle charges, which means it maintains or “trickles” a small charge to the battery. These tools are useful for keeping up maintenance on a good battery.

How to Use an Electrical Battery Maintainer
Electrical Battery Maintainer

You can connect the maintainer to an extension cord, rest it on a safe spot, and close the hood, and you can leave it charging for days, weeks, or months.

2. Maintainers and Chargers

Tools that can charge and maintain the battery will generally, and especially the new ones, have a microchip processor that allows them to monitor the voltage and turn the charge on and off as needed. If it doesn’t have a microchip processor, it won’t be able to manage the charge. These tools can also monitor and keep track of the battery’s health, and they are most useful for recharging a dying or older battery.

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How to Use a Battery Maintainer and Charger

car battery charger that can maintain or charge a battery
  1. Connect red clamp to the positive battery terminal and the black clamp to the negative/ground terminal.
  2. Press start. The device will tell you that it’s charging. It will charge to peak voltage and keep it there, turning off and on as needed.

Difference Between an Electronic Trickle Charger and a Battery Charger

There are a few differences between a maintainer and charger and an electrical maintainer that trickle charges.

  1. Trickle chargers are meant to maintain a battery, while a device that can maintain/charge the battery can restore it
  2. A trickle charger consistently trickles a charge while devices that can maintain/charge a battery turn on and off. This means trickle chargers can overcharge the battery, and maintainer/charger devices can maintain or give a little extra boost by charging
  3. Trickle chargers will have a thinner wire since less current is flowing

Like a trickle charger, older battery chargers will likely overcharge the battery, cause issues, and/or destroy the battery if it’s left on for too long. Since the wire is thicker on older chargers that run a consistent current, there will be less time to respond if it overcharges.

3. Charging, Maintaining, and Jump Starting

Devices that can charge, maintain, and jump start a battery have thick cables for all 3 functions since they will need to send a larger charge than devices that trickle or maintain a charge. They will likely plug into an outlet.

These devices also offer more than basic battery maintainers or devices that can also charge or restore the battery.

Smart Chargers

Smart car battery charger

Smart charger devices will tell you the battery’s charge by percentage. It will also tell you the voltage, amps, and it may have other functions like a boost, or a list of options for different batteries, like a glass mat or standard lead acid battery. If this is the case, make sure choose the right battery.

Some will only work once connected to the battery or a complete circuit, which also means you don’t have to worry about getting hurt if for example the cables touch.

Older Versions

Older car battery charger

Other likely older chargers consist of hooking up the cables and plugging the charger into the wall, turning the dial on, and charging the battery.

These chargers may not stop charging the battery until you turn the switch off or unplug it. If you leave it to charge and come back and notice a weird smell with smoke emitting from the hood, and upon further inspection the smell is pungent and smoke pours, you need to turn off the charger and unplug it, and then get the vehicle to a well-ventilated area. If you’re in a garage, open the doors as far as possible, because the battery is overheated and it’s starting to boil. Once it boils, there will be detrimental damage and it will need to be replaced.

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How to Charge a Car Battery - How to Maintain a Car Battery - 1A Auto
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How to Charge a Car Battery - How to Maintain a Car Battery - 1A Auto
Learn how to charge a battery if you want to recharge or maintain it. This article reviews the different tools you can use to charge or maintain your car battery
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1A Auto
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