How Long Can a Car Battery Power a Laptop

Have you ever encountered a power outage or embarked on a road trip and wondered How Long Can a Car Battery Power a Laptop? I had the same question and decided to dissect the numbers to discover the answer. 

A car battery can charge a notebook for 6.5 hours, a 45-watt palm book for 5.1 hours, or a 60-watt notebook for 3.8 hours with an inverter while still starting the car. Of course, it assumes that your vehicle’s battery is relatively new and in good condition. 

The amount specified on the PSU is the maximum concentration of energy that the laptop can draw from a power source, but it is not always required. 

How Long Can a Car Battery Power a Laptop

Frequently, it will be significantly less. In reality, I’ve often seen it at 1/4 the amount nonetheless because there are so many variables that affect a laptop’s power consumption. 

We’re going to use standard ranges to provide some estimates. In this segment, we will discuss How Long Can a Car Battery Power a Laptop? The two primary methods for powering a laptop from a car battery are using an inverter or connecting directly to the battery via a DC (direct current) cable.

How Can a Car Battery Be Used to Charge a Laptop?

Of course, this is a question that most drivers constantly ask when they are left in the dark after their laptops run out of juice. Consider the following scenario: you are camping, and your lecturer requests that you resubmit the assignment. 

Your computer has run out of battery power, and sadly, the job is not saved on your smartphone. The experience can be traumatic, as you know that these assignments and work reports frequently have deadlines. 

It is not as ugly as it sounds. With your car nearby, you can easily charge the laptop and complete the task. There are two methods for connecting the computer to the vehicle’s battery. 

To begin, you can connect it directly to the grid without using an inverter, or you can use an inverter. Whichever option you select will impact the charging time. Naturally, without the inverter, the charging time increases.

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How Long Can a Car Battery Power a Laptop?

The capacity of a typical automobile battery is greater than 50 amp-hours or 600 watt-hours. When the engine switches off, the battery can power a standard laptop (60W) for more than ten hours while still allowing the engine to start.

It recommends that the engine be turned on for 30 minutes every three to four hours to permit the alternator to charge the battery. While car alternators produce a negligible amount of power (300W) when idle, extending the battery backup by a few hours is sufficient.

If you want to charge your notebook while the engine is off, you can usually do so safely for about 1-2 hours. It will provide enough power for your laptop to function normally while also leaving enough juice in the vehicle’s battery to restart the engine.

However, performing this action repeatedly will reduce the battery’s life. It is why you should only perform this maneuver in an emergency and not while the vehicle is running.

How to Power Your Laptop in a Car Using a Power Inverter?

When it comes to charging your laptop in a car, the best solution is to use a power inverter. The inverter simplifies the connection and is completely safe to use with both the car battery and the laptop. 

It is only possible if you have the inverter. Additionally, you’ll need a functional cigarette lighter. As a result, if your car is not functioning properly, the charging process will be ineffective. 

Remember that you can’t charge the laptop while the vehicle is stationary. By doing so, you will quickly drain your battery. The following is a step-by-step guide on how to charge your laptop like a pro.


Compared to charging your laptop via a wall socket, using your car’s battery requires a special DC adapter. As a result, before beginning the procedure, you must ensure that you have the proper adapter. 

To make the adapter work, you must cut a segment of your power cord and replace it with a DC cord. The DC cord is perfectly sized to fit into a cigarette lighter socket in a car. What if you’re missing an adapter? You can easily obtain one at your neighborhood electronics store. 

Additionally, these adapters are inexpensive at online retailers such as Amazon. When purchasing an adapter, it is recommended to buy the universal version rather than the model-specific version. By doing so, you will avoid the misery associated with the need to top up a different laptop.

Connect the Adapter to the Laptop

It’s time to get to work after ensuring that you have the correct DC adapter and that it connects to the other end of your laptop charger. Begin by plugging the charger’s right end into your laptop.

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Put the Battery in a Safe Place

Continue to locate a secure location for the laptop while the charger inserts into the device’s charging port. Bear in mind that you must charge the laptop while the car is in motion. As a result, you should ensure that it is placed on solid ground to avoid damage while in transit. An empty seat is ideal for securing the laptop.

Connect the Dc End to the Cigarette Lighter in Your Car

Continue with the charger plugged into the laptop’s charging port and the DC end plugged into the cigarette lighter in your car. It’s the same as with a phone charger. As a result, that should not be an issue.

Start the Automobile and Drive

How Long Can a Car Battery Power a Laptop

With both ends of the charger connected, you should proceed to start the vehicle. The laptop should begin charging immediately, depending on the model you purchased. It recommends that you allow the battery to charge for the estimated period to avoid depleting the battery. By exceeding the anticipated time, you risk a flat battery and subsequent difficulty starting your car the next time.

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Can the Inverter Deplete the Battery in Your Car?

At the moment, power inverters come in a variety of ratings. Consider the 150W, 240W, 240W, 300W, and 500W. When charging your laptop in your car, a laptop charger with a power rating of 150W or 300W is sufficient.

With the capacity, you can anticipate your battery draining more quickly than when using a lower-rated adapter. If left connected overnight, the inverter can deplete the battery in your car. As a result, it recommends that you not use the inverter to charge the vehicle while it is idling.

FAQs – How Long Can a Car Battery Power a Laptop?

Can We Charge a Laptop After Shutting Down?

You can recharge the battery of your laptop regardless of whether it completely depletes. It makes no difference, even more so when a lithium-ion battery powers your laptop. Even when the laptop shuts down, the battery continues to charge. If you use the laptop while charging, it does not take longer to recharge the battery.

Can You Charge a Macbook in a Car?

Apple sells an official car charger for charging the MacBook in their marketplace. All that is required is a power port in your car compartment compatible with the car charger.

What Can a Car Inverter Power?

A car power inverter enables you to run low-power alternating current electrical devices such as computers, video cameras, and even televisions in your vehicle. We inform you of your available alternatives. Inverters enable you to run low-power AC electrical devices in your cars, such as computers, video cameras, and even televisions.

How Much Voltage Does a Laptop Use?

The majority of laptop chargers have a 19-volt rating. The difference in voltage between a charger and a battery allows the charger to power the laptop while also charging the battery (if they had the same voltage rating, the charger would only have enough ability to run the laptop).


Now, You are probably aware of How Long Can a Car Battery Power a Laptop? Charging a laptop to your vehicle is simple and safe as long as you follow the instructions in this article.

You can use your car’s battery to power various electronic appliances and gadgets via an inverter or direct connection. However, this has limitations. 

You can charge your laptop and run it off a car battery, but the operation’s duration depends on the battery type and the power consumption of your device.

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