Vivo has been using Dual-Engine fast charging on its smartphones. Its latest iQOO gaming phone featured 44W ultra-fast flash charge that lets you charge a phone with 4000mAh battery from 0 to 50% in 15 minutes, to 85% in 30 minutes, and 100% in 45 minutes. Now the company has showcased its new 120W FlashCharge technology that will let you charge a phone with a 4000mAh battery from 0 to 50% in 5 minutes and from 0 to 100% in just 13 minutes.