I have the same problem with my SM-T325 , i've tried everything on forums : reset, hard reset( vol menu button power button) nothing works !
Ps: I'm using genuine 2A white charger and even tried with Asus Nexus 7 charger 2A( ridiculously is that it works better than with the genuine samsung, the white one needs 5 unplug/plugs, with Asus Black charger only 3 unplug/plugs )
I had another interesting experience with this tablet.... it charged 100% without notice that the battery is full(I saw this tiny little detail -battery full icon- ensures that it is really charged) restarted it to verify something and shock !!! the value dropped to 62% and the charging sequence stopped ...and even if it shows "charging" while I'm typing these lines, it dropped to 59% ). pff !!!
PPS: The white charger works fine on my Galaxy S4 and i've installed an app that shows me the amperage during charging and it floats around 340 mAh - 600mAh - 990mAh - 3xx mAh and so on....(with both chargers - maybe it's a battery problem... but it's weird cuz if i manage to charge it completely, i do have a very good battery life )