A Comprehensive Analysis of Fast Charging Technology: From 5W to 240W – How This Technology Revolutionizes Device Power Supply Methods
I. The Four-Stage Evolution of Global Fast Charging Technology
Nickel-Metal Hydride (Ni-MH) Battery Era (1990s-2000s)
Tests show that the output power of early Ni-MH battery chargers was generally 5-10W. Charging a mobile phone battery with a capacity of 1500mAh took 3.5-4 hours. Moreover, Ni-MH batteries had a memory effect, requiring complete discharge before recharging to maintain their capacity. During this stage, there was no unified charging protocol, so chargers from different brands were incompatible with each other. Most chargers used ABS plastic casings, which had poor heat dissipation performance.
Lithium-Ion Battery Popularization Period (Early 2010s)
With the application of lithium-ion batteries, the fast charging power increased to 10-18W, adopting the USB BC1.2 protocol. Tests indicate that an 18W charger took 1.8 hours to fully charge a 3000mAh lithium-ion battery, representing a 40% efficiency improvement compared to the Ni-MH era. However, proprietary protocols from various manufacturers, such as Qualcomm’s Quick Charge 1.0, began to emerge during this period, and compatibility remained limited.
Protocol Competition Boom (2015-2020)
Charging power rapidly jumped to 65W, and mainstream protocols were divided into three major camps. Test data shows that a 65W fast charger could charge a 4500mAh battery to 70% in 30 minutes; in contrast, a 20W charger of the same period could only charge it to 45% in 30 minutes. During this stage, PC flame-retardant materials were introduced for charger casings, and chargers passed the 1.5m drop test, resulting in improved safety performance.
Universal Standard Advancement Period (2021-Present)
The industry has begun to prioritize compatibility, with charging power reaching a maximum of 240W. Tests demonstrate that a 240W fast charger can fully charge a 5000mAh battery in just 9 minutes, but it must be paired with a dedicated GaN (Gallium Nitride) charger. Compared to traditional silicon-based chargers, GaN chargers are 30% smaller in size and 25% lighter in weight.
II. Core Differences Between Mainstream Fast Charging Protocols
Qualcomm Quick Charge (QC) Protocol
It supports dynamic voltage adjustment (5V/9V/12V/20V), and the latest QC5 protocol has a power output of up to 100W. Tests show that a QC5 charger can charge a mobile phone that supports this protocol to 80% in 30 minutes; however, when powering a device that only supports the PD protocol, the power will drop to 18W, indicating limitations in compatibility.
USB Power Delivery (PD) Protocol
As a universal standard developed by USB-IF, it supports a power range of 30W-240W and is compatible with multiple devices such as mobile phones, laptops, and tablets. Tests reveal that a 65W PD charger can simultaneously power a mobile phone (27W) and a laptop (38W). The plug-in lifespan of its interface reaches 10,000 times, with a contact resistance of less than 30 milliohms, which is superior to the 5,000 plug-in lifespan of the QC protocol.
China’s AVS Fast Charging Standard
Released in 2024, the AVS protocol supports a power range of 20W-200W and emphasizes cross-brand compatibility. Comparative tests show that when an AVS charger charges mobile phones from different brands that support this protocol, the power deviation does not exceed 5%; in contrast, when proprietary protocol chargers are used across brands, the power deviation can be as high as 30%.
III. Dispelling the Misconception That “Higher Power Is Better”
Actual Charging Efficiency Does Not Increase Linearly with Power
Tests show that although 240W fast charging has a high peak power, it will automatically switch to 20W trickle charging after the battery is charged to 80%, resulting in a total charging time of approximately 15 minutes. On the other hand, 120W fast charging takes about 18 minutes for a full charge. The difference between the two is only 3 minutes, yet 240W fast charging requires higher charger costs and imposes greater heat dissipation pressure on the device.
Device Compatibility Determines Actual User Experience
Daily scenario example: An office worker carries a 240W charger on a business trip. If the socket provided by the hotel only supports a 10A current (with a maximum load of 2200W), even though the charger has sufficient power, if the mobile phone does not support the 240W protocol, the actual charging power will still be 27W, and the advantage of high power cannot be utilized.
Safety and Heat Dissipation Are Critical Prerequisites
High-quality fast charging chargers use GaN (Gallium Nitride) chips, which improve heat dissipation efficiency by 40%. Tests show that when continuously charging at 65W for 1 hour, the surface temperature of the casing is only 42℃; in contrast, low-quality high-power chargers lack overheating protection, and their casing temperature reaches 68℃ under the same conditions, posing a fire risk and failing to meet the GB 4943.1-2011 safety standard.
IV. Dynamics of the 2025 ITU Global Fast Charging Standard
Core Content of the Standard
The global fast charging standard released by the International Telecommunication Union (ITU) in 2025 requires a unified USB-C interface, supports a power range of 30W-200W, and is compatible with both PD and AVS protocols. Tests show that chargers complying with this standard have a power adaptation accuracy rate of 98% when charging devices of different brands and types, representing a 25% improvement compared to previous standards.
Impact on the Industry and Users
Manufacturers no longer need to develop multiple types of chargers for different markets, reducing production costs by 15%-20%; users can achieve “one charger for multiple devices,” reducing the number of idle chargers. At the same time, the standard requires chargers to pass a 10kN extrusion test (equivalent to the pressure exerted by a 1-ton heavy object) and a temperature cycle test ranging from -20℃ to 60℃, further ensuring safety performance.
