The most frustrating thing about Oppo's SuperVOOC fast-charging demonstration at Mobile World Congress is waiting for the battery to discharge so that they can run it again.\n\n\nOppo's VOOC fast-charging system, included in its high-end smartphones, can already charge batteries from zero to 75 percent capacity in 30 minutes. "We only put it in our premium smartphones because it's quite expensive to manufacture. You need a special charger and a special battery," said Oppo spokesman Marton Barcza.\n\n\nVOOC's successor, SuperVOOC, will fully charge a smartphone battery in under 15 mins, according to Barcza.\n\n+ MORE FROM MWC: See all the news from the mobile conference +\n\n\n\n\n\nAt Oppo's booth in Barcelona, it took just 8 minutes and 21.96 seconds to charge a 2500 mAh battery from 10 percent to 100 percent capacity, according to an app running on a prototype phone.\n\n\nThe prototype uses a modified micro-USB plug, longer than usual and with more pins, although it can also be charged, albeit more slowly, with standard micro-USB or USB C connectors, Barcza said.\n\n\nBefore beginning the accelerated charging, special controllers in the charger and phone verify one another's presence and the compatibility of the cable, which is especially thick. It needs to be, because even assuming a 100 percent efficient charge-discharge cycle, the demonstration charges at an average of at least 16 amps.\n\n\nUnfortunately you'll have to wait a good deal longer than nine minutes to buy a phone with a SuperVOOC charger.\n\n\n"The technology itself is quite mature. It's in the testing phase," said Barcza. "But when it will appear in a phone, I cannot say."