I actually had this same exact problem, and wrote a rather nasty review for the charger that I'd purchased. Their tech folks responded almost immediately and told me that my wall adapter was underpowered - that the wireless coils required greater than then 0.7A or even 1.5A typically produced by older chargers. I thought they were just feeding me a line but, in the interest of being fair, pulled out the adapter that came with the Galaxy S6 and noticed immediately that it was labeled as being an "
Adaptive Fast Charging" device with
1.67A at 9V, or a full
2.0A at 5V.
Using that adapter instead, the problems went away immediately. No more annoying "dings" each time the screen saver kicks in, no more charging all night long and only reaching 90%, etc.
Go grab the white wall adapter that came with your S6, and use it instead of whatever you're using right now. I think there is a good chance your problems will go away!
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