How to Charge a Car Battery the Proper Way

how to charge a car battery

Car batteries give power to vehicles. With constant use or disuse, car batteries drain eventually, causing them to lose power and die. Having a dead or weak car battery often means that it’s due for a replacement. However, sometimes batteries just need a little recharging to bring back their power. This is where knowing how to charge a car battery becomes valuable. 

In this article, we discuss tips to do it the right way while keeping yourself away from harm (since car battery acid is hazardous and requires precaution). 

Signs Your Car Battery Needs Recharging

There’s probably something wrong with your battery when your car refuses to start. While jump-starting your car might be able to bring it up and running again, it is not necessarily the best way to do it. If you don’t know how to charge your car battery, you’re in the right place to learn how.

How do you know when to charge car battery? Here are some warning signs to look for:

  • A slow starting engine
  • Dim lights and electrical issues
  • The check engine light is on
  • An old battery

Things to Do Before Charging a Car Battery

Car battery charging may be a simple task, but you should exercise caution when charging a car battery as it contains elements that could be dangerous if not handled carefully. Start with these steps before charging your car battery.

  • Refer to your owner’s manual
  • Find a safe place
  • Wear protective equipment (gloves, glasses)
  • Smell for gas leakage (smells like rotten eggs)
  • Check for heat and let it cool
  • Look for corrosion

Things You Need to Charge a Car Battery

Before you can charge your battery, you need to disconnect them first. If you don’t know how to disconnect a car battery, you can refer to this guide

Since charging a car battery requires disconnecting them, the tools needed are the same except for the car battery charger. Be sure to secure the following: 

  • Car battery charger
  • 10 mm open-end wrench
  • 10 mm drive socket wrench (check owner’s manual for reference)
  • Drive socket extension set 
  • Battery terminal cleaning brush
  • Battery terminal dielectric grease (optional)
  • Anti-rust spray (optional)
  • Gloves (optional)
  • Goggles (optional)

How to Charge a Car Battery

With all the necessary tools ready and set, you can now safely start bringing your battery back to life by following these 6 simple steps on how to recharge a car battery:

1. Prepare the car battery

Before you proceed with charging your battery, you need to prepare it first by determining whether you need to remove them out from your car to perform the charge. Some batteries can be charged as they are, while others require to be lifted out of their holding trays. With most conventional vehicles, you can charge your battery without having to remove them. 

However, if you’re in a situation where you need to remove your car battery to charge it, do so first to avoid mistakes and accidents. 

2. Switch off all car electronics

Once your battery is prepared for charging, make sure you turn off all the electronics in your vehicle, including any accessories like stereo or cabin lights. If your electronic are turned on while charging, there’s a high probability of your battery fuse blowing up or damaging your battery in the process.

3. Remove the negative (ground) cable

After confirming all powers are off, you can now start removing the negative cable from your car battery’s negative terminals. It is usually a black cable that is marked with a minus “-” symbol. Some batteries have a plastic cap covering their terminals. You need to remove them first if necessary so you could access the terminals.  Once you’ve gained access to the terminals, use a socket wrench to loosen the negative cable and push it far away from the battery. 

Important: Ensure that your wrench will not touch both terminals at the same time. This prevents your battery from shorting out or creating sparks.

4. Remove the positive cable

The same process applies here. Only this time you will be removing the positive cable. It is usually a red cable marked with a plus “+” symbol. Again, make sure both cables are far away from the battery. 

5. Clean the car battery

Since the battery cables are already disconnected, this is a perfect opportunity for you to clean the battery terminals. You can do so by using a brush and a cleaning solution. If you don’t have one, you can make your own by mixing baking soda and water. By cleaning the terminals, battery acid can be neutralized and malfunctions can be prevented as you charge and reconnect your battery. 

Note: Always use face and eye protection while cleaning battery terminals to ensure safety. 

6. Connect the car battery charger

With all the prior steps now completed, you’re now ready to hook up the battery charger. Here’s how you should connect your battery charger:

  • Make sure the battery charger is turned off before beginning use
  • Hook the positive cable on the charging unit to the corresponding positive terminal of your car battery.
  • Repeat the process and hook up the negative cable to the negative terminal. Do not reverse the process.
  • With both cables connected, you can now turn on the charger. Start by setting it to its lowest rate. If it comes with a timer, set it for the appropriate charge time. 

How Long Does it Take to Charge a Car Battery?

The charging time depends on the charger. But with a 20 amp charger, it usually takes 2-4 hours for the car battery to be fully charged.

What to Do if the Car Battery Won’t Charge?

If your battery won’t charge, you can perform a load test to rule out other possible problems. If it turns on, then your battery isn’t the problem. 

Frequently Asked Questions

Can you charge a car battery with another car?

The simple answer is yes. Charging a car battery with another car is called a jump-start. Here’s a guide on how to jumpstart your car. 

Can a completely dead car battery be recharged?

Car battery chargers can regenerate power into a battery. Keeping it plugged for 24 hours can recharge your battery fully.

Can you trickle charge a car battery when it’s connected?

Yes. In fact, you can only trickle charge your battery when it is connected to your vehicle. However, you won’t be able to revive a totally flat battery. 


Charging a car battery is not a complicated task. You can easily do this on your own. However, make sure you do it in a safe place and follow the above-mentioned guidelines carefully to ensure your safety. 
But if after completing each step you still can’t charge your battery, know that Neighborhood Roadside Assistance is here to help. We offer a fast and reliable battery replacement service that will charge up your battery in no time.