Plugging in multiple power sources does the right thing

[anarcat]

Say I have my Framework laptop plugged in its charger. Say I’m tired and distracted, and think “oh, i need to plug in this laptop” and find a stray USB-C cable lying around your desk and yank it in ANOTHER USB-C port.

What happens then?

Do both ports get used for power? Does the entire laptop blow up in a puff of smoke?

Does the laptop start sending power back into the power grid?

A discussion on the Matrix channel seemed to indicate it will generally not explode, but I’m not sure it will do the right thing which is, I think, use the better power supply for charging.

[Morpheus636]

The laptop will only charge from one port at a time. I’m not certain how it picks a port, Kieran would know the answer to that.

[GhostLegion]

@anarcat Assuming both sources are USB-PD, during the negotiation process, the computer will pick whichever source provides the most power. Only one port will provide charge at a time. It’ll be fine.

[Azure]

@Morpheus636

Kieran would know the answer to that.

USB-C charging

@John_Comeaux the laptop will only charge from one port at a time. It chooses the port with the highest available power. This is due to a hardware limitation, as we only have one charge controller, and charging from multiple ports would require per port load balancing. I do not think many, if any laptops would support this feature.