Multi-port USB chargers tested for simultaneous charging efficiency

Tests conducted by Canaltech evaluated whether using multiple USB ports on a single charger significantly slows down the charging process for individual devices. Using a Samsung Galaxy S26 Ultra as a reference, the study compared charging speeds when the device was connected alone versus when two other smartphones—an iPhone 17 and a POCO M7 Pro—were connected simultaneously to a charger with two USB-C and one USB-A port.

When connected alone, the Galaxy S26 Ultra took 52 minutes to charge from 15% to 100%. When all three ports were in use, the charging time for the Galaxy increased to 58 minutes, representing a difference of only six minutes, or approximately 11.5%.