[kelvie]

You'd need a battery with UPS-like functionality (and doesn't beep when it's taken off power), otherwise every time you plug and unplug it your mac would restart.

Which is surprisingly hard to find for a portable (usb-C) battery.

[PhasmaFelis]

Does it do that? Why?

[kelvie]

Do you mean why a UPS beeps when it's disconnected from power? I imagine so the user knows it's disconnected.

Annoying during a power outage though.