I have Samsung S4 almost 5 months old, It takes around 4-5 hours to complete charge the battery. Couple of months back it took about 10 hours to charge and cannot even connect to PC, All other devices are working fine on my PC, it is just the S4 keeps disconnecting automatically every after 3-4 seconds. I have visited Samsung service center 3 times and each time they replace the adapter. Once adapter replaced, it will charge from 20% to 100% in 1.5 hours.
Now again after a month or so i have same issue. it is taking almost 4-5 hours to charge, Now i requested for replacement as it is a faulty piece and Samsung support saying that it is normal/by design it should take that long. They are not even ready to give in written that it is normal to take 4-5 hours charging. My Cousin has S4, that charges full battery in less then 2 hours.
It looks like i have wasted my money, Samsung neither repairing my mobile nor they giving replacement.
Don't trust Samsung, they are cheaters.