Watts vs. current. At 300mA, that's 1.5W of power. Maximum current draw on a pi4 is 3A (~15W), but that's purely a power supply input limitation. You only get

Watts vs. current. At 300mA, that's 1.5W of power. Maximum current draw on a pi4 is 3A (~15W), but that's purely a power supply input limitation. You only get close to that with a ton of peripherals and heavy load on the Pi.