A month ago I noticed my phone was only slow charging, and I was using the factory charger, the adaptive fast charger, I did some troubleshooting, and came to the conclusion my charger was getting funny. So replaced it. Now, no matter which one I use, the factory charger or the Anker +IQ, it still slow charged. Now on occasion it won't charge at all and takes unplugging and plugging it back in to have it charge. I've cleaned the ports several times but it doesn't seem to help much.
Maybe it's my phone itself with the issue?
Thanks for reaching out. I can certainly understand your frustrations regarding this. When plugging the charger into the port, is it secure or does it wiggle? Have you tried using a wireless charger?
Also, Try giving this article here a shot to help you with the symptoms you are experiencing.