How Does Fast Charging Work?

Today, whatever gadget you have, whether smartphones, laptops, cables, and chargers, manufacturers are always talking about fast charging. Fast charging is often used to promote chargers and other devices that are capable of charging faster than the current charging standard, which is 5 watts. In the present time, technology allows for a quick charge during limited downtime, and it is best for those who have busy day-to-day lives. 

This is the reason why when you search for chargers in stores and online, you’ll be able to find lots of offers for fast chargers. There are even fast chargers that can accommodate more than one device, just like the Fast Charging Station for Multiple Devices by COSOOS . This kind of fast charger will enable you to charge all of your devices, like smartphones, smartwatch, and earbuds, all at the same time. 

But what does fast charge really mean, and how does fast charging work? If you are also curious and you want to know how before buying fast chargers, then read on. Today, we are going to give you a guide to understand how fast chargers work. 

How Fast Charging Works

smartphone connected to a fast charger

To better understand how fast charging works, here are some of the things you need to know:

  • Amperage, Voltage, and Watts

Amperage, voltage, and watts are the basic components of charging. Amperage, or also known as current, pertains to the amount of electricity flowing from the battery to your phone or other device connected to the charger. Voltage pertains to the speed or strength of the current. And when you multiply amperage and voltage, you will get watts. If you compare it to a watering hose, the amperage or the current is the width of the hose, the voltage is the water pressure, and the watts is the amount of water coming out of the hose. 

  • How Fast Charging Turn Up the Speed?

In charging, there are two phases. In the first phase, the charging rate is increased by a higher voltage. What fast chargers do is that they control this phase to increase the flow of power. When the battery has received most of its charge, the charger will then decrease the voltage to prevent overcharging and overheating. This ensures that your device and charger are both safe. 

  • How Do You Charge Faster?

Before deciding to use fast chargers, it’s important to note that you will need the right equipment. Your devices, such as laptops, smartphones, and tablets, will all need to use the same fast charging standard. In fact, there are times when your cable should also be compatible with the fast-charging standard used in every device and fast charger you have. 

Once you have the compatible charger and cable for your phone, laptop, and other devices, you need to take note of the maximum charging speed for both your charger and device. For example, if your charger has 27 watts and your smartphone has a maximum charging speed of 18 watts, then this means that your phone will charge at 18 watts. 

Keep in mind that not all chargers are fast chargers, and not all devices support fast charging. Therefore, before using a fast charger to charge your phone, make sure that your device is equipped with a fast-charging feature. If you use a fast charger on a phone that does not have a fast charging function, then your phone will be charged at a normal speed. 

  • Is Fast Charging Safe?

Many people also wonder if fast charging is safe. Since these technologies enable your devices to charge faster compared to standard charging speeds, you may notice your charger and device to become warm while charging. But fast charging is safe if you ensure that you are using high-quality chargers and cables that have certifications. When you use fully certified accessories to charge your devices, fast charging is as safe as standard charging. 

Fast Charging Standards

phones charging

When looking for fast chargers, here are some standards that you might encounter:

  • USB Power Delivery: USB Power Delivery or USB-PD is the official fast charging specification. It can be used by any device that has a USB port, provided that its manufacturer includes the needed circuitry and software. It augments the basic USB charging speeds for up to 100W of output power. This way, the amount of available power is split into different power ratings, which work at a different voltage. For phones, 7.5+ and 15W+ are best. For laptops and other higher power devices, 27W are best. 
  • Qualcomm Quick Charge: The Quick Charge technology by Qualcomm was once the default standard in the smartphone industry. It was popular before USB Power Delivery was introduced. This standard can work on a wide range of phones, including LG V40, Samsung Galaxy Note 9, Xiaomi Mi 9, and more. There are also lots of legacy chargers and third-party accessories that you can find which uses this standard. 


Fast charging includes lots of different possible technologies, and each of them has its own pros and cons. This is the reason why there are now lots of fast chargers available in the market, and each company or manufacturer has their own approaches on how to speed up charging and maximize the longevity of your device’s battery. We hope that the information we shared gave you an idea of how fast-charging works.