Find the right laptop AC charger

Laptop charger - How to find the right charging cable for your Laptop

You always have your laptop with you and you also use it frequently. The battery lasts a long time, but you often use the device with the power adapter. In addition, the battery must also be charged in between. But then the day came when your charger failed. Now you have to make sure that you get a new one as soon as possible. Does it have to be an laptop charger, or can you simply use any other one? These are the questions you have to deal with now. We will give you all the informations you need to know on this topic.


How do I find the right charger for my laptop?

white Macbook Charging

Every commercially available power adapter is compatible with different laptops. This means that no laptop has a power adapter that is designed exclusively for use with that particular model. Often, these chargers can fit laptops from different manufacturers. Nevertheless, it is advisable to choose a power adapter that is sold by the manufacturer of the device. If the matching adapter is not available, other models can be used. They have to fit the device exactly, otherwise damage can occur. To find a compatible power charger, the values of the previous model should be compared with those of possibly matching variants. The following information is needed for this:


Every user knows the manufacturer of the laptop that is used. If that is not the case, the manufacturer's name can also be found on the device's.


This refers to the operating voltage of the laptop. This is provided by the power supply and is specified in volts (V). It is important that this operating voltage is exactly the same between the laptop and the power supply. The corresponding value can be found on the old power supply under "Output". The voltage number can also be found on the laptop's bottom and in the user manual.


The power of the charger is defined by the amperage. It is important that the amperage is at least as high as it is indicated on the old Laptop charger. If the value is higher, this is not a problem. So you should make sure that the amperage of the power supply is the same or higher than the amperage of the laptop. In no case should the amperage be lower, this can lead to damage. The current is indicated in amperes (A). Usually, this information can be found directly next to the voltage information or below it.


The power is specified in watts (W). It does not play a role when looking for a new power supply, as it is calculated from voltage x amperage.

Plug dimensions

Connector dimensions are usually given in the format outer diameter x inner diameter, in mm. There are a few tolerances in this range. It is recommended to make sure that the deviation of the connector dimensions is less than 1 mm.

When searching, the manufacturer should be specified, as well as the required voltage and amperage . If the corresponding power supply units were found, only the plug dimensions have to be checked. It is always important to make sure that the voltage in volts and the plug dimensions always fit the laptop perfectly.

Does it always have to be a laptop charger directly from the manufacturer?

It is not absolutely necessary to buy a new power supply directly from the manufacturer. It is definitely the easiest option. It is usually quite eays to enter the product number at the manufacturer store or the exact name of the laptop, and the right power supply can be found. The power supply will fit the laptop perfectly. If the original charger is no longer available you hve to search for based on the required specifications. Alternatively, a universal laptop charger is a good solution.

Power supply from the manufacturer

What should I consider with a universal adapter

Besides the usual power supplies, there are also so-called universal power adapter charger on offer. Here it is always important to make sure that these devices are really safe. They should have the CE mark. In addition, it is important that the connector plug fits the laptop. Universal power supplies usually come with different tips, so they can fit many different ports by using the appropriate adapter. For models that are only designed for a certain voltage, you have to make sure that it fits the laptop. There are also universal power chargers that are equipped with a voltage regulator. These allow the adjustment to different voltages, so they can be used much more flexibly.

Universal power adapter

What are the consequences of using an incompatible adapter?

If a power supply is used to operate a laptop that is unsuitable for the device, serious damage can occur. It can quickly happen that the power supply overheats and damages the laptop's battery. In the worst case, even the laptop's motherboard can be damaged. A repair can become very expensive and in many cases is not even possible. When buying a power supply, it is important to always make sure that it fits the laptop perfectly.

What does AC input and DC output mean on a laptop adapter?

On each adapter there is certain information that is important for which devices the power supply can be used with. Among other things, this is also input and output information, which is often found on it in the following form: AC INPUT and DC OUTPUT.

The abbreviation AC stands for "Alternating Current". DC, on the other hand, is the abbreviation for "Direct Current". With alternating current, the polarity of the current is changed at regular intervals (50 times per second). This creates a balance of negative and positive directions. Alternating current (AC) has numerous advantages, which is the reason why it is most widely used worldwide.

It is a fact that batteries can be charged better with direct current (DC). That's why DC power is used not only for laptops, but also for smartphones and tablets. AC current comes from the wall socket. Accordingly, the DC current must be converted. This is the task of the power supply unit. The AC input means that alternating current flows into the power supply unit, is then converted into direct current and passed on to the laptop via DC output.

What kind of plug is needed for the laptop

Laptop wih interchangeable tips of universal power adapter

A look at the laptop's user manual is enough to find the dimensions for the plug. These are usually given in the following scheme: Outer dimension x inner dimension in mm. If the user manual is no longer available and no information can be found online, you can simply measure by hand. It is absolutely necessary to be very precise when doing so. It is very important to really determine the exact dimensions. Since there is no standard for the hollow plugs for laptops, finding a suitable model is not exactly easy. In this case, a universal laptop power adapter with different tips is often the best choice. Most common plug sizes are included, so the plug of the power supply can be adapted with it and plugged into the port of the laptop. There are also some laptop manufacturers that equip their plugs with very special characteristics. For example, this may be a pin in the middle. Then a special adapter is often necessary, which is not included in the scope of delivery of a conventional universal power adapter.

How many watts does my laptop need?

It is quite easy to determine how many watts the laptop requires. The information can either be found on the label on the laptop's bottom or directly on the power supply's label. There you can usually find all the important data, including the wattage. If the wattage can't be found there, it can easily be calculated using the other data. For this, volts and amperes are needed. The calculation goes like this:

Volt (V) x Ampere (A) = Watt (W)

Can I use a different universioal charger for my laptop?

If another power supply offers the same output voltage and at least the same or a higher amperage and the plugs also fit, such a power supply can also be used. It is really always important that the values fit, otherwise damage can occur.

Is it possible to use a stronger or weaker one?

That depends on the range in which the power supply is stronger or weaker. When it comes to voltage in volts, it should always exactly match the voltage of the laptop. A power supply that has a voltage that is too low can cause the device to not work. In the worst case, the battery can be damaged. A voltage that is too high is even more dangerous, not only for the power supply itself, but above all for the connected device. A voltage deviation of 5% is considered harmless. The deviation should not be greater in any case. It is therefore not advisable to exchange a power supply with 16 volts for one with 20 volts. The maximum current of the power supply (amperes) may be higher, but in no case lower. In this case, the power supply could become very hot, and there is even a risk of fire.

Can I charge my laptop with a powerbank?

The small but very powerful powerbanks are very popular today. With them it is possible to charge mobile devices quickly and easily. This is also possible with a laptop. This requires a suitable powerbank. Conventional models are not suitable for this due to the connection and also the lack of capacity. So, a suitable powerbank has to be bought first. Certain high-performance models with a capacity of more than 50,000 milliampere hours are best suited for this. This makes it possible to charge a laptop even twice. This depends on the model of the laptop. Such a special powerbank also has disadvantages. For one, it is not exactly light, it can weigh quite two kilos, and for another, it is very expensive.

When buying the powerbank, make sure that it fits the laptop. The decisive factor is what power the laptop needs. In addition, the laptop must have a DC output or alternatively have a corresponding adapter. Ideally, the powerbank should also offer overvoltage and discharge protection. Charging the laptop is as simple as activating the powerbank, connecting it to the laptop and letting it charge.

Can I charge a laptop with a USB cable?

It is possible to charge a laptop via a USB cable. A very specific USB type is required for this. Charging only works with a USB port type C. This type has already been installed in various devices since 2015. It is possible to charge the laptop via this. A suitable cable is also needed for this. If a laptop has a USB-C 3.1 port, it is quite possible that it can be charged via it. More information about this should be found in the user manual. The cable should already be included in the scope of delivery.

How to charge a laptop without a cable?

There are ways to charge a laptop without a charging cable. This often requires a few detours, it is generally possible to use other power sources for charging.

Charge laptop via other laptop

Some laptop models can also be charged with the help of another laptop. A USB charging cable is required for this. This connects both devices with each other. Not all laptops provide this option. Information about whether a laptop can be used for this or not can usually be found in the laptop's description.

Charge laptop using car charger cable

All laptops can be easily charged in the vehicle with an adapter for the cigarette lighter. All that is needed is the appropriate car adapter. One end of the charging cable is simply connected to the lighter. At the other end, there is either a simple USB plug or also a plug that fits the power connection of the laptop. Plug it in, charge it, and you're done.

Charge laptop with docking station

Usually, there is a suitable docking station for every laptop, which is compatible with the device. Thanks to such a docking station, it is possible to charge the laptop on the go.

How much power does a laptop consume per hour?

That depends entirely on the laptop. In general, laptops consume much less power than desktop computers. Many factors play a role, including the graphics card, the screen size, the processor and also the ventilation and lighting. For example, a laptop with a power rating of 60 watts that is used for four hours a day costs about 10 cents a day. This assumes an electricity price of 30 cents. The power consumption per hour is therefore very low, but varies from device to device. Therefore, no generally valid statement can be made on this question.


If the laptop power supply has a defect, there are several ways to purchase a new charger. Replace a laptop power supply is quite simple. There are only a few important values that must definitely match the values of the laptop. If you pay attention to this, it's not absolutely necessary to buy the often quite expensive original replacement power supplies from the manufacturer. Third-party models or universal laptop charger also fulfill their tasks very well. Just make sure that the selected power supply is really compatible with your laptop. Then you can use other power supplies and do not necessarily have to rely on an original replacement.

Created: 28 October 2022