I am currently using xiaomi 10400mah powerbank and I love it so much. It is pretty fast when charging on phone, estimately takes 2-3 hours to get fully charged per time. This powerbank is able to charge my Note 3 Neo for 2 times. 

**gentle reminder for beginner, you need to plug in the cable on the powerbank tightly. Mostly people thought their powerbank is not working or ruined, but actually you need to plug in tightly in order to use it. :)