How To Charge a Car Battery Without a Charger?

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Last Updated on May 2, 2022 by Ellis Gibson (B.Sc. in Mechanical Engineering)

Most vehicle owners or drivers know that car batteries are charged constantly by the car’s electrical system. Actually, it’s true and it means that you have no reason to pull out the car battery for this purpose. 

Car batteries can be used for other purposes outside the car. Knowing how to charge your car battery without a charger will come in handy. So, how do you do it?

Simple 07 Steps To Charge Your Car Battery Without a Charger

Step-01: Collect your car parts

Before you search online for solutions, consider safety precautions. Remember, dealing with a car battery means that you are handling toxic chemicals, significant current, and voltage that are running through those terminals. Start by collecting items such as

  • Sturdy gloves
  • Protective eyewear
  • Wire probes with clips
  • Three holiday lights
  • Jumper cables

The items enable you to recharge your car battery safely. Safety is a priority, and the holiday lights provide illumination for current control. 

Step-02: Choose a power supply

You need some kind of power supply to enable a slow charge of your car battery. Think in the line of energy reserves present. For instance, the technician’s bench may have some power supply. Also, you can use another battery with a similar voltage. However, ensure the power source is reliable as a dead battery will only give you more frustrations in charging. 

Step-03: Check your output power

Slow charging your car battery components is the best approach if you don’t have a charger. The resultant trickle effect prevents your car battery from overcharging, exploding, or fuming. Volatile conditions are unhealthy for the battery. Therefore, you need to maintain a charging session. 

Start by checking the output power on your power source using the wire probes. Verify your current and voltage. Also, check the voltage on your questionable battery. It helps give you a rough idea of how long to expect the charging session to last. 

Step-04: Add the lights

Place your battery and power source far from each other. The spacing is necessary to ensure you are charging the car battery components safely. It prevents sparks from forming between the two devices, which can cause an explosion or harm. Connect your three-holiday lights between your car battery and the power source. The role of the lights is to give you visual cues when the current is flowing. Besides the lights draw down any intense current to ensure you have an effective charger that works perfectly.

Step-05: Connect your clips

Now you are ready to connect the power source, car battery, and lights together. Place this set up far away from traffic or other people. Choosing the best place to charge your car battery component is vital for safety reasons.

Start by connecting the negative clip to your power source then attach the remaining negative clip to the car battery to complete the circuit. Do the same for the positive clip and when done, power should be flowing. 

Step-06: Watch the setup

The setup will be trickling power as your car battery gains some voltage for the next 10 to 20 minutes of the charging process. To know the progress, use a multimeter attached to your car battery terminals. Also, at this point, the holiday lights are illuminated with some heat on the exterior surfaces. 

If the holiday lights get excessively bright or hot, it means there is much power running to your battery. To remedy the situation, disconnect and troubleshoot your setup.

Step-07: Remove the setup and verify power

After like 30 minutes of charging, remove the power from the car battery by unplugging the negative clip first followed by the positive clip. Use your multimeter to know the battery voltage without the power supply load. 

It’s not a must that the battery be charged to 12 volts and overcharging is not good for the battery lifespan. Therefore, you are safer charging the car battery to a partial state as it doesn’t cause harm to your battery or bring safety issues. 

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Is There Another Way To Charge The Car Battery Without a Charger?

An alternative approach involves using your jumper cables and another car. Maybe your friend has another car or you have a good Samaritan willing to assist.

Follow the steps below to get it done.

  • Take out your jumper cables from your kit. The cables have metal clamps on both ends and colored in black and red, showing negative and positive respectively of the charged and charging car. 
  • Be ready with one or two friends who will help you jump-start the car.
  • Turn the keys on the off position and ensure the car is safe and will not move. If you are on a slope, engage the parking brake then lift your car hood. 
  • Place the negative sections of the jumper cables on the battery terminals. Place your black clamps on the car’s metal frame to ensure the connections are secure. Alternatively, you can place the black clamps on your black terminal and the other end of the black clamp on your good car battery’s negative terminal. 
  • Place the next pair of your jumper cables on the positive terminals of each car. Positive terminals are red. The red clamp goes on the positive terminal of the car battery to be charged and the other red clamp to the positive terminal of the good battery. Tell your friend or good Samaritan to start their car first and let the car run for two minutes. 
  • Allow the car battery to charge for some minutes before starting your car. The car will start immediately. In case the car doesn’t start, wait for the charging to continue for a few more minutes before trying again.
  • Once the car starts, allow it to run to gain charge before you turn it off. Disconnect the cables as the process is complete. Try starting the car again to be sure. 


The above-discussed two methods are very useful in charging your car battery without a charger. Always ensure your toolkit has the above-mentioned items and other necessary tools when traveling. You can help someone in trouble or be the one in trouble and get help. It’s difficult to use the steps above if you pack the items mentioned. Therefore, invest in them and read the process discussed above carefully as you will find them useful in emergency situations. 


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