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Can I Charge Car Battery With 12V Adapter?


Owning a car doesn’t mean knowing everything concerning car performance. The complex electrical system of the car plays a vital role, and you should treat it with great concern. The battery charging system is the key player in every car running tool. So, can I charge car battery with 12v adapter?

A 12v adapter can recharge the battery but only to 12v. To fully charge your car battery, you must raise the voltage to 13.8v. Using a 16v adapter can spoil your car battery due to the heat produced. The heat production is because the 16v adapter raises the voltage too high; this can damage your battery.

Do you need to expand your knowledge in everything concerning adapters? You should be in the right place. Explore more in this article.

What Is the Difference Between Adapters and Chargers?

Adapter  Charger
Adapts and converts the voltages  Takes electric current out of the adapter
Charges a charger  Charges battery
An AC adapter converts current to DC  Some chargers convert AC to DC
Helps in providing power supply  Not all the chargers work the same

Before we go deep, let us discuss the difference.

Charger vs. Adapter

Like other electronics, you can confuse the working of an adapter with that of a charger; they all seem like they perform the same thing, but they do not. However, their work complements each other.

The adapter helps to charge a charger—the adapter helps in providing a powerful supply of power and converts AC to DC.


Chargers help to charge electronic devices by taking power from an adapter. Your car charging system works in the same way as simple chargers. The only difference is that you may not use an adapter for the simple chargers.

Some of the simple chargers can convert AC to DC. It’s not the same case with a car charging system; you’ll always need an adapter to help in charging your car battery.


For every electronic tool, adapters perform an essential role in protective charging. Generally, adapters help connect two electronic items and make them work together. In cars, adapters help tap electric energy and use the latter in charging the car battery.

However, the car battery’s safe and total charge heavily depends on the type of charger you use. Higher voltage chargers can cause overheating of the battery, hence damaging it.

Before charging your car battery, consider the type of adapter that best fits car battery voltage.

Besides, only two types of adapters exist in the market (the AC and DC). Depending on the type of electrical current you need to tap, you’ll have to choose the correct adapter.

Car Batteries and Power Supplies

The 12v battery being the industry standard mainly for cars, differs from the deep cycle batteries. You’ll find six cells in a 12v car battery, each having 2.1 volts when charged fully.

The 16v cells have eight cells that charge 16.8 volts. You’ll find the 16v batteries mainly used in the race cars. Let us stick to the 12v variety throughout the article.

You’ll find most of our cars using 12-volts lead-acid batteries. But, you can recharge these batteries. They can only store the charge, but they cannot generate the power themselves. However, this battery will need a charging system or power supply. If you need the car battery to fully charge, ensure a higher terminal voltage above the 12v.

Can a 12-Volt Power Supply Fully Charge a Car Battery?

The 12v power supply can charge a car battery, but it’s not the safest way. For your car’s complete and safest charging, you should use a power supply of around 13 volts.

Whenever you charge the battery with insufficient voltage, it can sink the charging source. It’s because the current required increases as the battery gets charged. It’ll reach a point where no charging takes place. It cannot supply more current as required by the car battery.

As soon as the battery resistance is below charger internal resistance, it’ll need more current to charge.

When the charger current does not exceed that of the battery, then the charger starts withdrawing battery power.

Whenever you lack a charging option, it’ll be better to take out the battery from the engine bay. It’ll help in preventing electronic damage. Keep the battery in a well-ventilated room at room temperature when charging.

You should wear safety gear like gloves and eye protection when charging the car battery. Observe the battery temperature and voltage when charging. After a few hours, it would be best if you get a crank. Most of the adapters with a 12v DC power supply have over-current protection. So whenever you use it, you’ll not experience overheating problems.

However, it’ll be very hard to predict the outcome. You should never lightly use lead-acid batteries when handling.

How Long Will It Take to Charge a Car Battery With a 12V Charger?

It takes almost 12hrs to charge a car battery with a 12-volt charger. However, the time taken depends on the current capacity of the power supply and how draining the battery is. The safest way of charging your car battery, turn the car off together with the electrical devices.

Slow charging is the best option to ensure the battery doesn’t heat up.

Can You Charge a 16-Volt Battery With a 12-Volt Power Supply?

It’s impossible to charge a 16v battery with a 12-volt power supply. The 12v power supply can only raise the battery to 12v, but the 16v battery requires more current power. You should know that under-volt charging is harmless.

Is It Possible to Recharge a Dead Car Battery?

You’ll find it possible to recharge a dead battery using a good-conditioned car. You should jump-start or push-start your car. Switch off the car’s electrical devices and run the car with an idle engine.


You can use a 12-volt adapter to recharge your car battery but only 12 volts. If you need to charge your car battery fully, you must use a 13v adapter. A 16-volt adapter can cause overheating to your battery, eventually damaging it.

However, do not forget safety measures while charging a car battery in an open space at room temperature. Car batteries produce dangerous gas while charging. They should always be treated with respect. Besides, the acid from the battery can severely harm. Use the correct charger for your lead-acid battery.

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