Macbook Pro 2016 15" poor charging when connected to monitor

Hello guys, yesterday i received my second 2016 15" MBP, after returning the first one I got because it was freezing and the battery was horrible. Well after a day's use with the second one the battery problem still remains, though it only froze once when I tried to change the resolution in World of Warcraft. Anyway, another problem has emerged and it's really frustrating. When i connect the MBP to my external monitor (Acer 27" H277HU ZeroFrame 2K IPS Monitor With USB C hub) the battery either says it's not charging or charging time more than 10 hours. I've already tried resetting the SMC, nothing changed.