S21 Ultra Wireless Fast Charging Doesn't Work With USB-C to 3.5mm Headphone Jack Adapter

[userqWNLESRrD6]

I think I discovered a software bug with the wireless charging feature on the S21 Ultra. I recently bought a Qi wireless charger for my car that supports wireless fast charging (10W). For some reason, whenever I plug in a USB-C to 3.5mm headphone jack adapter (Samsung EE-UC10JUWEGUS) it changes the charging speed to a slower one. As soon as I unplug the jack adapter it goes back to fast charging. I tested my phone out with other Qi chargers that support 10W fast charging with and without the jack adapter and I get the same results. I then tried plugging in a normal USB-C cable (not connected to any power source) and the wireless fast charging worked fine. Therefore, the problem must be with USB-C to 3.5mm jack adapter. I tried using an older Note 8 with the jack adapter and the wireless fast charging worked fine. This is rather annoying because my car does not have Bluetooth and I need that adapter to listen to my music, get directions from google maps, and make calls.

[user751201tmO21]

Interesting ... we have the new Samsung wireless tri charger ... and I have the Samsung USB-C to headphone jack adapter ... I will test this in a bit

BTW, just to let you know, there are USB-C charging cables that have a 3.5 headphone jack splitter, though I'm unsure of the quality

[userqWNLESRrD6]

Thanks for testing this out. I knew about USB C splitters being a thing, but I had extra cash to splurge and thought a wireless charging car mount would an elegant solution to my problem.

[user751201tmO21]

Well, you're correct ... I see the same behavior ...

It takes longer to wirelessly charge the phone when the USB-C adapter is plugged in.

Check out my screenshots - one with, and one without, adapter, and showing estimated charging time.

[userqWNLESRrD6]

Man this is such a niche problem, I wonder if Samsung will fix this. Any idea who I can report this to?

[user751201tmO21 · Accepted solution]

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