How Long Can a Car Battery Power a Laptop

When you’re engaging with no access to power, and you’re heading to a location where you won’t have access to electricity, what will your car’s battery be able to do for your laptop?

Like my former question, I conducted a little investigation to get an answer.

A car battery can charge a laptop. But How Long Can a Car Battery Power a Laptop?

When a car battery powers a laptop for 6.5 hours, a laptop powered by 45 watts can run for 5.1 hours, and a laptop powered by 60 watts can run for 3.8 hours when equipped with an inverter.


If you can assume your car battery is healthy and not uses for a long time, this should work. When you add up the PSU block (the adapter on your charging cord) with what your laptop will pull from a power source, you end up with the upper limit of what your computer uses. But this number does not represent the level of power required all the time. Even if it is less, it may still be challenging to achieve. Mostly what I’ve seen is 1/4 of the actual quantity.

We will, however, continue to use a universal standard range for our estimates as so many different elements affect laptop power usage (graphics card, brightness, volume, streaming, and several programs). Laptops with automobile batteries can be powered in two main ways: an inverter or DC (direct current) cable, without an inverter.

First, I will explain what a car battery is, how it works, and it’s capacity. Additionally, I will explain how inverters are inefficient, explain why a laptop chord is better than a traditional cord, and explain DC to DC connections. Then I’ll give a detailed analysis of each laptop type and a description of the various powering ways.

How to Charge Your computer Using a Car Battery?

How Long Can a Car Battery Power a Laptop

No matter where they are, every motorist asks themselves this question whenever their laptop batteries run out of juice. Say, for instance, you are camping out in the great outdoors, and suddenly your lecturer emails you, asking you to submit the homework all over again. Unfortunately, the work saves on your smartphone.

Studying these work reports and assignments can be painful because you know that you must hand them in with time constraints. While it doesn’t have to be as hideous as it sounds, it does not have to be lovely. Without your car, you have to cope with the laptop powered, which adds anxiety to the situation.


Follow the below procedure to know How Long Can a Car Battery Power a Laptop?


Instead of plugging your laptop into an outlet in your home, use your automobile batteries while using DC power instead. It would help if you verified that you have the correct adapter before beginning the operation. You will have to remove a power cord section and replace it with a DC cord for the converter to work. This DC cord is making to suit the vehicle’s cigarette lighter socket flawlessly.

What if you don’t have an adapter? 

You may purchase one at any electronics store in your area. Finding these adapters is easy, too. You can find them on Amazon. It is advisable to get a universal adapter as opposed to a model-specific adaptor. When you take this approach, you’ll escape the anguish resulting from updating your laptop’s content when you’ve already topped up a different one.

First, Connect the Adapter to Your Laptop:

Once you are satisfied that you have connected the correct DC adapter to your laptop charger and links to the other end, it is ready to begin. Place the appropriate end of the charger into your laptop, and then start.

To Prevent Damage, Place the Battery in a Secure Location:

To begin charging, insert the charging cable into the device’s charging port. Next, locate a place where may place the laptop safely. Remember, when you’re on the move, you must trust the computer. Therefore, you should guarantee that it is set on a stable foundation not to be damaged when moving. An empty seat does an excellent job of safeguarding the laptop because it provides a suitable place to store it.

Plug the Dc (or Din) Power Cord Into Your Car’s Cigarette Lighter:

You can continue charging your laptop with the charger plugged into the DC port in the computer, then hit the DC end into your car’s lighter. Just like a phone charger, you would do the same thing with this. Thus, no issues should arise.

Turn the Key in the Ignition and Hit the Gas:

Should start the vehicle while the charger connects on both ends. The computer will start charging as soon as it’s turned on, and that depends on the model you purchased. Your battery should be allowed to continue charging until it has fully recharged so that you don’t drain your battery. Forgetting to charge your car’s battery before leaving the house can lead to a flat battery on your return, necessitating another trip to the charging station.

 How Long Can a Car Battery Power a Laptop?

It is rather difficult to explain, as a car battery can be considered a “starter battery” and a “deep cycle” kind of battery. The internal makeup of a car battery consists of thin lead plates with more surface area for conducting current. It can stress itself (2-3%) for around two to three seconds before beginning to provide power to your vehicle. 

After you start driving, it gets recharged by the alternator. You won’t get more than ten or so total discharges by powering different gadgets or appliances with the discharged battery because it would be damaged by doing so.

Furthermore, deep-cycle batteries include more substantial plates, protective alloys on the dishes, and a smaller surface area, enabling them to go through hundreds of full or partial discharges.

Ineffectiveness of an Inverter When Charging My Laptop:

It is the most commonly employed manner that individuals would use to power laptops when they buy it new. You will need an inverter to charge your battery if you want to keep doing that. An inverter transforms DC battery power into AC power, making it possible for you to power your gadgets with it.

By inverting this power, inefficiencies and heat dissipated. The average inverter will have an inefficiency of roughly 15 percent. Some people are more, while others are less. We will use a 15% inefficiency (or 85% efficiency for those “glass half full” people) for our calculations.

Ineffectiveness of Laptop Port:

Laptop power sources are never 100% efficient even when you are running them off wall power. The cord you are following connects to a rectangular box in the middle. It is the PSU, and it converts the 110-volt AC electricity coming from the wall into 19-volt DC.

Despite your laptop plugs into your house’s alternating electricity, it runs on direct current (DC). Inefficiencies that occur in the PSU include the inverter, and 10% is a reasonably common percentage.

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

  1. Can You Run a Laptop Off a Car Battery?

    You will need a power inverter (a DC to AC inverter) that enables you to plug in almost any electronic gadget into your car's battery. However, in a DC charger, you will not able to utilize the cable provided with your laptop for charging.

  2. Can We Charge Laptop With 12v Battery?

    The laptops can't use this charger since most of them require a 16V power source powered by a 19.5V, 4.5A charger. If the 12-volt battery cannot power the laptop, then the laptop will not work. Instead of using adapters, you might use cars.

  3. How long can a car battery power?

    Once a battery has lost its ability to generate enough power to start an engine, it has completely degraded. Another factor influencing the rate at which a battery age is vehicle usag


Many studies indicate that How Long Can a Car Battery Power a Laptop? is an important question. Charging the laptop when the automobile is running is an excellent practice.

An automobile inverter is required. To be able to select an inverter, you must be able to provide a 12V power source. Unless you have a long-lasting battery installed, don’t charge your laptop when the automobile is not running.