Xiaomi's 100W Charging System

Xiaomi has announced that they have a system that can charge a 4000mAh battery in 17 minutes. At 100W*.

(100W in marketing speak. 80-88W in the video.)

I’m half excited and half afraid. I’d also like to know what effect it has on battery longevity.

Xiaomi's video showing 4000mAh being charged in 17 minutes

Xiaomi’s “100W” quick charging goes from 0 to 100 in 17 minutes

The video shows a charging race between two phones, Xiaomi’s unnamed “100W” prototype and a phone with “50W” charging from “Brand O”, which looks like it’s an Oppo RX17 Pro. I put both of these wattage ratings in quotations because neither phone actually hits its rated charging speed. Xiaomi’s video shows a live, in-line power reading, and the “100W” charging shows a sustained ~80W (18V / 4.5A) from about 5-30 percent, with a peak of 88W. The competing 50W Oppo quick-charge solution caps out at around 40W.

Unfortunately, Xiaomi didn’t offer any specifics on how its charging solution works. Dissipating heat, which slows charging and degrades the life of a battery, is a major concern when charging this quickly. Oppo’s charging solution (branded “Super VOOC” in Oppo phones and just “Fast Charge” in OnePlus phones) solves this issue by duplicating the heat-generating power management circuitry inside its proprietary power brick.

Written on March 28, 2019