If a power strip has multiple USB ports, why can’t they all charge at max power at the same time?

Question

If a power strip has multiple USB ports, why can’t they all charge at max power at the same time?

In: Engineering

Answer 1

Same reason that you can’t just plug in full-wattage heaters into every socket in your house.

Sure, the socket may be rated for that, but the thing supplying it likely isn’t rated to run EVERY SINGLE socket at max 100% of the time.

So though you might get, say, 2A from a single port, you can’t get 2A from EVERY port at the same time if the whole strip has a limit of 5A for all ports, and it has, say, five ports.

The adaptor that does let you do that will be bigger, more expensive and use more power generally (i.e. be less efficient when you have less plugged into it).