Fast chargers juice up your phone quick, but pose risks for some older devices
Charging speeds for mobile phones have hit a new milestone: A phone can be juiced from zero to 100 per cent in 25 minutes.
The breakthrough, achieved by a slate of new smartphones from Chinese makers, places their charging speeds well ahead of the offerings of big boys such as Samsung, Google and Apple.
Specifically, flagship models from Chinese smartphone makers Oppo, Honor and OnePlus come with the latest ultra-fast 100-Watt (W) chargers, which takes just 25 minutes to achieve a full charge to last for a day’s use.
Wattage indicates the amount of electrical current pushed towards the phone; the higher the wattage, the higher the amount of energy and the faster the charge.
Comparatively, the latest flagship models like the Samsung Galaxy S23 series, the Google Pixel 7 and Apple’s iPhone 14 generally use 20W to 45W chargers and can take more than an hour to achieve the same full charge. For instance, the standard power brick for iPhones charges at 20W will fill up the device in around 1.5 hours.
The latest of these fast-charging phones is the Oppo Reno10 Pro+, the first in the Chinese manufacturer’s line-up in Singapore to come with its 100W SuperVOOC Flash Charge technology that can fully charge the phone in around 20 minutes.
Released in July, it follows other recent devices that also come with proprietary 100W fast chargers, like the Oppo Find X6, Honor Magic4 Pro and the OnePlus 11.
Oppo said its breakthrough comes from software upgrades in its latest in-house SuperVOOC chipset that protects the battery from the high influx of electrical current.
Developed by Oppo, the new SuperVooc S chip and accompanying software allow lithium-ion batteries to safely receive high amounts of electrical current that is typically used for much bigger batteries, said the Oppo Reno series senior product manager Joe Lin.
OnePlus, which shares the same supply chain and manufacturing facilities as Oppo, also uses similar software for regulating electrical current flow when the battery is almost full to prevent overcharging and overheating.
Similar to Oppo, it’s latest fast-charging phones use a dual battery system, with each battery receiving half the wattage from the 100W charger to fast-charge safely, said a spokesman for OnePlus.
Honor said it also uses software to regulate the influx of electrical current, but declined to comment on whether it built its own fast-charging technology and on its development, citing internal policies.
During charging, lithium ions are shuttled between two layers of electrodes – typically graphite and metal oxides (such as lithium manganese oxide) – inside a battery, creating a flow of electrons that powers a device.
New lithium-ion batteries are also using more silicon-based materials to improve the structure’s resistance to warping, and manganese-based materials to stretch the lifespan of batteries.
The capacity of lithium-ion batteries is reduced - what is known as battery fade - when a battery is overcharged, causing it to heat up, said Dr Chiam Sing Yang, deputy executive director of A*Star’s Institute of Materials Research and Engineering.
Overcharging typically happens after the 80 per cent charged mark if the flow of current is not regulated well. “Battery management software today can prevent too much current from passing through the battery,” he said.
Battery fade can also occur during fast-charging, when electrical current passes through its layers too quickly that the lithium ions are in the bottom of the battery do not get time to charge up and move between the layers, said Dr Chiam, who is also the technical director of the Singapore Battery Consortium, an innovation group for battery development. He noted that the lithiums left behind will become “dead” overtime.
This problem can be overcome by battery management software. In the case of Oppo, its software is able to track in real time the activity of the bottom lithium ions inside the battery to adjust the charging current to minimise the risk of dead lithiums, prolonging its battery’s lifespan, said Mr Lin from Oppo.
The Oppo Reno10 Pro+ and the latest 100W-charging phones by Honor also stop charging once the phone’s battery is full, such as during overnight charging.
Experts warned that ultra-fast chargers should not be used for older devices that are not installed with such advance charging management software to prevent damage to their batteries.
Phones today have gradually overcome major bottlenecks to faster charging by building safer battery materials with a better balance of materials and better software, said Associate Professor Xu Yan from the Nanyang Technological University School of Electrical and Electronic Engineering.
He said: “I think Chinese smartphone manufacturers are usually faster adopters of new technologies over other brands. Over the years, they have invested significant resources in for both software and hardware.”