Where does the electrical power come from? For Example, how does Phillip power his Commodore 64 computer?
Using magic you can change the "settings" on any object, including electronics and batteries. In this case, we can assume that they've hacked the Commodore to always have a full charge in the Power Supply Unit, negating the need for an external power source.
They set the laptop’s battery to constantly be full, like Martin’s phone. For internet access Martin simply used Wi-Fi to tether the laptop to his phone so he could access the phone’s 4G connection, a process that thoroughly confounded Phillip. Martin patiently talked Phillip through it as they went. He enjoyed playing teacher to Phillip’s student, instead of the other way around.
Off To Be The Wizard: Chapter 18.
It has likely been hacked to not need power, or from the Commodore's perspective to be plugged into an infinite source of power.