Battery Full Charging time anker battery w/ samsung charger

Hello guys,
i'm using galaxy s4 i9500 n i just bought anker battery 5200 mah and 7600mah
1. How long should i charge my battery anker 7600 and 5200 mah using original samsung charger ?

i charge each anker battery from 10% to full about 2h 30m and the icon battery was already 100% .
2. Why it's same time when i charging my original samsung battery 2600 mah ?

my gadget doesn't rooted yet.