I want to give 5v to my ebike (broken 5 volt regulator). I have a usb power bank with an output usb at 5v 1a. When I measure the voltage when nothing is plugged in or just a cord is plugged in, I get .77 volts. When I measure the voltage when my phone is in I get 5 volts and my phone says it’s doing 1 amp. So how do I get the power?