I purchased this power bank two months as I m using mi note 3.
So the battery of mi is 4000 mah I needed some backup because whenever I travel for two days I don't keep the charger with me.
So In the last month I went to pune I fully charged my battery as well as powerbank.
I was using the phone without any hesitation of battery drainage as I kept power bank with me.
When I was about to reach pune my battery was 20% so I connected the phone with powerbank this was the first time when I was using powerbank.
It fully charged my mobile then it run till night when I again thought to charge I took power bank out so what I saw it was showing only one point I thought it might be light problem I connected it with mobile.
After one hour I saw instead of charging my battery was reducing and my phone switched off.
Then I went to mobile shop and instantly I had to purchase charger really such a pathetic powerbank it charged only once as I was thinking at least it can charge three time.
Mean I wasted 7 k behind this. So guys don't go for it in the same price you can get other powerbank which can be reliable.