Recovery charging

Hello everyone! I have an issue. My 2015 12 inch macbook has only 1 usb-c port. I made an oclp MacOS Sequoia pendrive and plugged in so i can boot to the pendrive. Everything worked in the recovery but when i tried to install the system to the disk, it said"plug your mac to power" or something like that, and as i said, theres only one usb-c port and the pendrive is using it. Can someone please please help me???? Im stuck on big sur