Using 65w charger on 45w laptop

Oftentimes, we find ourselves looking for substitutes for our technical devices in certain situations. Which is why most laptop users tend to use laptop chargers of a lower wattage power adapter. Although this seems like a nice hack for a while, there might be a few consequences of using a lower wattage charger for your laptop.

Also Read: How Many Watts Does It Take to Charge a Laptop?

What Does Charger Wattage Mean?

To put it simply, the wattage indicates the amount of power that can be drawn in once your laptop is connected to the power outlet. Each and every single charger has its own level of wattage, which is why they are categorized as either “high wattage chargers” or “low wattage chargers”.

How Exactly Does a Laptop Power Supply Work?

We can compare the power demanded by your laptop with the need for lighting in your room. Although you might be alright with dimmer lights or lights with lower brightness levels and power such as 45W or 60W bulbs, they won’t be as effective for when you need extremely bright light for work.

Also Read: Can I Leave My Laptop Plugged in Overnight?

Similarly, the supplied power supply of your laptop is built to handle and endure the worst possible charging conditions. And although it may seem to function normally in most cases, it won’t be getting enough power to run high capacity programs.

Once your charger has been plugged into the wall socket, the AC power is automatically converted into DC power and transmitted to the motherboard. The motherboard will then distribute it to various other parts of your laptop, especially the battery as it will be storing DC power that can be used later.

Can I use a Lower Wattage Charger for my Laptop?

The answer is yes. You definitely can use a lower wattage charger for your laptop (you can even charge your laptop without a charger!), but this will directly impact the performance of your laptop itself. For instance, using a 45 watt charger for a laptop that requires 90 watts might not enable it to function at its maximum potential. Again, this greatly depends on the type of activity being carried out on your laptop itself.

Also Read: Laptop Won’t Turn on OR Charge [FIXED]

For instance, if you’re using your laptop to read some article, or if your laptop stays idle with minimal brightness level, the low wattage charger will work perfectly fine. But if you plan on watching a video or a movie at high volume, it is highly likely that your laptop rejects the power coming in through the charger, and switches over to the DC power stored in its battery. Since the laptop will not be gaining any power through the low wattage charger, it will ultimately shut down once the battery runs out.

Also Read: Can You Use a Laptop Without a Battery?

Using a low wattage charger for your laptop will be more of a frustration, rather than a convenience to you. Based on multiple reviews and experiences by users, as well as professionals, it can become quite difficult to properly charge your laptop through a low wattage charger. Since the power trickles in slowly, it might take hours to fully charge your laptop, which is definitely not an ideal situation if you’re in a hurry.

It is possible to charge your laptop battery externally (without a charger) using the USB-C port.

What are the Risks Associated with Using a Low Wattage Charger for your Laptop?

With a low powerage, you can potentially cause a fuse in the power supply, damaging it and various other components of your laptop. Since your laptop will be charging at a slower rate than usual, despite having a high current, the battery of your laptop will get ruined as well. The life of your battery will be substantially reduced, and it will get drained at a much faster rate as well.

Also Read: How to Replace Laptop Battery Cells

Most users also complain about their device and the adapter overheating, since it takes a longer time for the battery to fill up. These cooling problems could also have some other negative impacts on your device, further reducing the performance and capability of your laptop.

There will also be the risk of breaking some components of your laptop as they will be demanding power, but will be unable to get it due to a power shortage resulting from using a lower wattage charger.

Also Read: Laptop Lags Slows Down When Plugged In Charging? [FIXED]

When you use a lower wattage charger, the voltage regulator inside of the motherboard adjusts the voltage in the current to match with the requirements of the internal components of your laptop. This way, you can easily power up your device with a lower wattage charger that has a minimal difference than the one actually required to power up your device. For instance, you can easily charge your 20V PC with a 19V charger without any complications.

But if the difference ends up being significantly higher, you might end up facing complications with the voltage regulator, so much so that it ends up failing or breaking down.

Is it Possible to use a Lower Wattage Charger Without Harming your Laptop?

Realistically, there is one situation where you could use a lower wattage charger without negatively impacting your device and its performance. If you plug in your laptop when the battery is fully charged for external power support, you can avoid both overheating your device as well as ruining the life of your battery.

In case the battery of your device is not charged, make sure that you’re not currently using the laptop while it charges. Doing so will further protect the life of both your laptop, as well as its battery.

Although it isn’t recommended to use a lower wattage charger for a substantially high powered device due to the complications that can occur from it, professionals have deemed it to be safe to use when in a sticky situation. Continuous usage of a lower wattage charger will, however, will be risking serious damage to your precious device.

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Posted By: Elliott Published: 02/07/2019 Times Read: 171812 Comments: 33

Question: Can I use a laptop charger with a higher wattage?

The short answer is yes you can use a laptop charger with a higher wattage, however, there are some caveats. The wattage rating of a laptop charger is a maximum rating which means that the charger is capable of providing power up to the output wattage rating and or course anything in between. 

A brief explanation of Volts, Amps and Watts.

A commonly used analogy to explain the concept of Volts, Amps and Watts is to think of electricity as water flowing through a pipe. Amps is the amount of water flowing through the pipe, Voltage is the water pressure ie. the speed at which the water is pushed through the pipe and Watts is the power exerted by the water when it exists the pipe at the other end.

Amps and Watts are Related.

Watts is calculated by multiplying the Volts by the Amps. Therefore a 19V charger with an Amps rating of 3.42A would be a 65W charger 19V x 3.42A = 65W. The higher the Amps the higher the Watts, provided the Voltage remains constant.

It's a Maximum Rating.

The Amps and Watts rating on a laptop charger is a maximum output rating. This means that the charger is capable of outputting up to the maximum Watts rating. ie it can push up to x Amps of water through the pipe at a force of up to x Watts at the pressure (Volts) provided by the charger.

I'm still confused. Can I use a laptop charger with a higher wattage?

Yes, Your laptop has been designed to draw up to a certain amount of power when running at full power. When the laptop is idle it may only draw a small amount of power from the charger but when you are rendering a 4K video for your youtube channel and charging the battery at the same time, the laptop is going to be drawing a lot more power. The manufacturer would have calculated the maximum power draw of the laptop and will have supplied a charger with a sufficient maximum rating to be able to provide this power. This means that you can quite safely use a charger with a higher wattage (or amps) rating as the laptop will only ever draw the amount of power required at the time. If your laptop was supplied with a 65W charger we know that the laptop will never draw more than 65W, so you can use a 65W, 90W,120W, 150W, 180W, 240W or higher charger. You can not use a charger with a lower wattage rating. A 30W or a 45W charger can not supply sufficient power for your laptops needs which means you could damage the laptop and/or the charger.

The Caveats.

I said in the beginning that there were a few caveats. 

1. The Voltage needs to be the same or at least very close to that required by the laptop. We would generally not recommend using a charger or more or less than 1V of what is required by the laptop. HP have 18.5V, 19V and 19.5V laptops and we've never had a problem with supplying either of these charger for any HP laptop. Fujitsu laptops generally require 20V, but we've never had a problem with 19V chargers. You can not however use a 15V charger on a laptop that requires 19V or vice versa.
2. The output tip needs to match. There are many types of tips. There is the traditional barrel tip which is a simple barrel shape connector with a hole in the middle. These are measured in the form of 5.5mm x 2.5mm which us the external and internal diameter of the tip. These need to match or else the connector will not fit or will be too loose. Some chargers have a small pin in the centre and some manufacturers (HP and Dell) that have what is known as a smart tip, where there is some electronics in the tip which is used to communicate with the laptop to ensure the correct charger is connected. Whilst these tips are physically the same size, you can not use a Dell charger on a HP laptop or vice versa. 
3. The Polarity must match. Barrel connectors usually have the negative on the outer sheath and the positive inside the inner hole and to be honest we have never come across a laptop charger which is different. However, to avoid any damage to your laptop it's usually a good idea to check the polarity against that of the laptop or your original charger.

A Laptop will normally use a positive polarity. In 10 years at The Laptop Power Supply shop, I've never seen anything different.