[HELP PLEASE] samsung galaxy s5 battery charging problem

Why my samsung galaxy s5 battery is charging slow?


see i have the external charger as well which came with my phone
my phone is korean model
charger model --> ETA-U90KWK
battery 2800 amps
i required 4:18 hrs to charge from 3% to 100%
while on site like youtube people says 2 hrs r enough
i am using it in india