but it can also prevent accessory plugs from making contact. When non-metallic objects fall into a cigarette lighter or 12v accessory socket, you won't end up with a short circuit or blown fuse.

Depending on how the end-point negotiates with the charger, either 5V, 9V or 12V outputs are supported. You can dig into the details in Qualcomm’s Quick Charge Patent [PDF] which shows how ...