USB-A - USB-C cable with 100W [closed]

Question

I have a Xiaomi phone that shows 3 options when connecting the charger: Charging, Fast Charging and Turbo Charging. (Not sure which wattage is each one)

I have a fast charger that when I use a USB-C - USB-C it shows Turbo Charging.

I bought a Baseus USB-A - USB-C cable with 100W. But when I use in the same fast charger it shows only fast charging. I did some resource and the USB-A has very limited power output.

I also tested charging a drone battery, with the C/C it charges fast but the A/C charges slowly.

Is this 100W a lie?

Answer 1

The cable itself might be rated for 100W when used with e-marked USB-C plugs.

But, there is no way you can expect any standard USB device to provide or consume 100W when there is a Type-A connector involved.

There are no official standards for negotiating that over Type-A, and likely no connectors that are rated to handle 100W over Type-A.

However, custom solutions with custom connectors may exist. For example a 100W SuperVooc charger can output 9.1A at 11V on Type-A connector which is 100W.

So your cable may really support 100W.

Your current charger and current phone might not.

Answer 2

USB-PD only works on the type C connector; A-to-C cables do not and cannot support it.

There are other protocols, like Qualcomm Quickcharge, that work over a standard USB cable with any type of connectors, but they have to be supported separately by both the charger and the device being charged. USB-PD has basically replaced these in modern equipment.

Answer 3

Maybe a lie (or the cable is faulty/damaged). The cable has to have a chip in it (and AFAIK the type A is also non-standard).

Consider this Xiaomi 120W rated charger with a USB-A to USB-C. There's a 6A rated cable and the device can negotiate 20V.

For more than 3A the chip is required or the power supply should not deliver the current. Without the chip the limit would be 3A at 20V or 60W.