How To Charge A Car Battery Without A Charger (6 Best Ways)

The problem of a flat battery on your car is common to everyone. There are several reasons why a car battery wears down, and there are several ways to recharge it. Most people often try to figure out how to charge a car battery without a charger.

However, the best and safest way to charge a car battery is with the appropriate charger. This charger is specifically designed to charge the battery of a car.

If you don’t have a battery charger and want to know how to charge a car battery without a charger, here are some methods to try out.

How to Charge a Car Battery Without a Charger Using Jump Leads and a Donor Vehicle

How to Jump-Start a Car

The jump lead and donor vehicle are the most common way to charge a dead car battery.

Using jump leads is a safe and easy way to ignite a vehicle that has a dead battery when you do not have access to a car battery charger.

The jump leads method will charge only enough battery to ignite the car while the alternator takes over the battery charging process. Nevertheless, if the battery charging system or alternator is faulty, jump leads will not be very helpful.

The battery charging jump wires help transfer power from the donor battery to a dead battery.

It is important to follow and read the owner’s manual of both vehicles before hooking up the leads.

Because modern cars are susceptible and have complicated electrical systems, that is to say, when connecting the jump leads, it should be in a certain order to avoid damage to other electrical components.

How to Jump-Start a Car

Step 1

As a driver, always carry an auto repair kit in your trunk in case of emergencies. This portable kit includes a flashlight, screwdriver, extra fuses, blanket, and other tools that you may need, such as jumper cables.

Step 2

Bring out the jumper cable from the kit. The jumper cables are covered with red and black plastic material. These two colors stand for positive and negative terminals of the charged and charging car.

Step 3

you should fully charge your cell phone in case of an emergency. It is better to call a family member or friend who will meet up with you and help you jump-start your car or find a nearby mechanic shop to assist you to jump-start your vehicle.

Step 4

Before performing any process of jump-starting your car, make sure the key is turned to the “off” direction. And also, ensure the vehicle is in a safe position and if you are on a hill or slope, engage the parking brake (hand brake).

Step 5

You should connect the negative jumper cable to the negative terminal on the battery. Also, connect the black clamps on the metal chases of your car. Fix the connection firmly to avoid movement.

But in case you don’t have a secured connection, put the black clamps on the black terminal of the battery and carry the other end of the black clamp to the negative terminal side of the battery.

Step 6

You should also connect the positive jumper on each car’s battery’s red positive terminal side. Then connect the red clamps on the positive terminal of your vehicle.

Connect the other end of the clamps on the battery’s positive terminal. The charging car, which is the leading car, will start first for about two to three minutes.

The weak battery should be allowed to draw power for a few minutes. Then start the car immediately and if the car refuses to start, still allow it to charge for more time.

Try it again, and once the car engine starts running, you will allow the battery to gain enough charge before disconnecting the cables.

But there are other few tips or ways of jump-starting a car.

These tips are:

Tip1: always check if the battery terminal on the dead battery is free from corrosion and dirt before connecting the jump leads cables and clamps. If there is dirt, clean with a brush wire or use a baking soda solution.

Tip2: Make sure the jump leads provide enough power to start the dead battery. The number of gauges should not be more than six; it is preferable to have four gauges to ensure the current moves safely without melting the cables.

Tip3: The donor car engine should be allowed to run for 15 minutes before starting the vehicle with the dead battery. This process will ensure enough charge in the dead battery to start and keep the engine running.

Also Read: Car won’t start? Causes and How To Fix

How to Charge a Car Battery Without a Charger Using a Solar Panel

How to Charge a Car Battery Using a Solar Panel

The solar panel or the solar battery charger is another way to charge a car battery without a charger.

This charging method is not very effective but is safe and straightforward if you know how to charge volts and amps. When the car battery is dead, charging by this method is not wise.

A dead car battery takes 8 to 9 hours to charge fully, depending on the amount of current produced to charge the battery and the battery size.

A solar panel charger is not the best, but if you decide to use a solar panel to charge your car battery, you must know what you are doing. You should carefully observe a solar panel when using it to charge your car’s battery.

We have two different ways of hooking a standalone solar panel to a car battery. One way is always recommended, which is the solar charger controller. the first way is using a solar charge controller. Typically a 12V solar charge controller.

The solar charger controller controls the currents that flow while charging a battery and prevents overcharging of a battery.

Another way you can use a solar panel is by using a solar panel battery charger. This is an excellent way to recharge a car battery. The solar panel charger is safe; it protects the battery’s lifespan by not letting the battery overcharge and stops it from going completely flat.

The size of your car battery determines the size of the solar panel needed to charge it and also determines the time it will take for the battery to fully charge.

For example, a 100W solar panel charger will produce about six amps of current. The current generated would be enough to charge a car battery from a flat to a full state, which usually takes about 8 to 10 hours.

How to Charge a Car Battery Without a Charger Using a Home UPS Inverter

How to Charge a Car Battery Using a Home UPS Inverter

The UPS inverter is a system that converts DC battery power to AC battery power. The UPS inverter is installed in our homes as backup power in a home or business place. The inverter carries an inverter battery of about 12V, enough as backup power.

The inverter battery is a battery that can be used to power things in our homes (electrical appliances) just for a short period when there is a power failure.

There are many different inverters, but the tubular inverter battery is the most common. It is the most popular inverter used as backup power in campsites, RVs, and even in homes.

You can also use the UPS inverter to charge a car battery. However, check the manual or handbook to confirm that charging a car battery with that particular inverter is safe.

Some inverters have safety measures that monitor the battery’s voltage to prevent overheating and overcharging. Before charging your car battery, it is important to determine the inverter’s strength.

How to Charge a Car Battery Without a Charger by Putting the Battery Into Another Vehicle

When you have a flat battery and don’t have access to a charger, your next option is to find a car with a similar battery to the flat one and then charge your flat battery with it.

This method is less effective without a battery car charger. It mainly benefits older, simpler vehicles because their electrical systems are less complicated. But this method can be useful to charge a car battery used in an RV or campsite.

But before changing the battery for charging, there are a few things you need to consider.

  1. Ensure the dead battery is of the same size and shape as the other car.
  2. Check for the mAh rating of the dead battery and that of the donor vehicle.
  3. When Charging a dead battery with a donor vehicle, you will have to jump-start the car after installing the dead battery.
  4. You must note that before performing this process, make sure the car engine is switched off and every auxiliary electricity is switched off. Once this precaution is followed, you can install the dead battery in the donor’s car.
  5. If the car battery is dead, you will need to jump-start the vehicle for the dead battery to be revived by the alternator.
  6. When placing the dead battery in the car, ignite the engine to run for a few minutes (20-30min) or gently drive the vehicle around to charge the battery fully.

Also Read: How To Test An Alternator (3 Best Ways)

How to Charge a Car Battery Without a Charger Using a Portable Car Jump Starter

How to Charge a Car Battery Using a Portable Car Jump Starter

Using a portable car jump starter may not seem very clear at first, but it will make sense once you figure it out. The jump starter is not used to charge a battery;

it is like a trigger to start a car’s engine; meanwhile, when this happens, the alternator immediately picks it up to charge the dead battery.

Here are a few tips when using a jump starter.

  1. Before fixing a dead battery, always check the battery’s condition before starting the engine. Check if the battery is old or completely dead before jump-starting the engine. If it is, there is no point in doing so. Always use a multimeter to check if a battery is in good condition or not.
  2. Turning off or disconnecting the lights, audio equipment, phone charger, air conditioner, and auxiliary electrical systems is a good idea. These few components drain the battery and may make the jump starter ineffective.
  3. Ensure the battery is free of dirt and corrosion before connecting the jump starter.
  4. Make sure you turn off your vehicle’s engine before connecting the jump starter, as failure to do so may damage the vehicle’s electronic system.

How to Charge a Car Battery Without a Charger Using a Battery Isolator

Battery isolators are very important, and they are a popular choice for RV drives and regular campers. The isolator enables you to charge a secondary battery using electric power from the alternator.

The isolator sends some current generated from the alternator to another battery. This does not provide enough current to charge the flat battery fully.

While the engine is running, the alternator does some minor work, such as charging the primary car battery that is supplying power to other auxiliary systems installed in the car.

It is beneficial to top up a 12V vehicle battery because it can be used as a power source while camping or in an RV. Solar panels are also an excellent alternative way to charge a secondary battery.

Here is a video demonstration that teaches and explains battery isolators. The video shows how to fix them to power a car battery.


It is important to always have your charging kit with you as a driver. Having read this article, you should have been able to determine what to do when you have an unannounced emergency and need to charge your car battery quickly.

Whenever you are trying to charge your battery with any type of kit, you need to be cautious and follow the manual, so the cable is connected correctly. Failure to do so might damage electrical components and other delicate objects in the car.

But if you don’t feel confident you can handle it yourself, you should seek the advice of a professional mechanic or take your vehicle to a workshop.

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