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40W fast charging purportedly degrades battery 3x faster than 15W charger

[ UPDATE 14/05/2020 21:30 ]: Oppo has reached out to us to dispel misconceptions about its SuperVOOC 2.0 charging technology. They have provided battery test results conducted both in-house and by TÜV Rheinland. More details here.


Various Chinese smartphone makers are pushing the limits of fast charging for smartphones. These days, it is not uncommon to see the latest flagships boasting 100% charge under 60 minutes. However, if you’re planning on using your devices for an extended period of time, it appears that these insane charging tech is doing more harm to your phone’s battery.

According to Anandtech writer, Andrei Frumusanu, Oppo has confirmed that 40W charging degrades a battery capacity to 70% in the same cycles as a 15W charging would to 90%. That’s a degradation of 30% versus 10% for using a significantly higher charging output.

It is worth pointing out that Oppo still probably has the highest commercially available wired fast-charging technology with its 65W Super VOOC 2.0. It is offered on the Oppo Reno Ace and the latest Oppo flagship, the Find X2 Pro. The Find X2 Pro’s 4,260mAh battery can be charged fully in just 38 minutes.

Most recently, Oppo has finally jumped on the wireless charging bandwagon by introducing the 40W AirVOOC fast charging technology. The Oppo Ace 2 is their first device to support wireless charging and it can get a full charge in just 56 minutes.

SEE ALSO:  Oppo to introduce an insane 125W fast charging tech this week

At the moment, not all manufacturers are obsessed with ultra-fast charging speeds. For example, Apple has been sticking to its slow 5W charger for the longest time and it is being still offered today as standard on the iPhone 11 and the latest iPhone SE. The fastest they support at the moment is 18W via USB-PD. Unless you get the iPhone 11 Pro series, you’ll have to have to purchase the 18W charging brick and USB-C to lightning cable separately.

A slower charger is better in prolonging a battery’s lifespan and as it puts less strain and produces less heat. The battery lifespan is probably the least of your concerns if you’re the type that replaces your phone every single year.

Are insane fast-charging speeds really necessary? Perhaps you’ll need it during an emergency or when you need a quick top-up from a powerbank. Personally, I would rather have a phone with a long battery life that can last a full day under heavy use. A slower 10W-18W charging would suffice if it’s going to be left charging overnight.


Alexander Wong