I have a tablet Samsung SM T-805 (Tab S 10.5"). Also I have Samsung A5 2016 phone and original Samsung adapter (2A 5V).
I had custom OS installed on my tablet. At some moment it became to charge really slow. So I have installed Android M on my Tab S. Also I installed 3C battery monitor. First charge after reistalling was fast. In fact it was close to 2A. But now charging rate is only 0.5A. Also 3C shows that battery is in good state.
I don't think that problem is with cable/adapter: A5 shows 1A current while charging (I think it's limit for it).
What I suspect:
- Usb plug-in is damaged.
- Android is limiting charge rate. I think it's more likely since battery had charged faster right after reinstalling Android.
In case 2 there might be a possibility to somehow remove that limit, but how? If it requires root access it's not a problem.