It works extremely well and recharges the mobile very fast and fully. I charged the Power Bank after I received it and left it lying in my rucksack for about 14 days before I need to use it. It was quietly showing a charge of 3 LEDs. So the discharge time of the device itself is very slow When not connected to anything. Even After That I was able to fully recharge my mobile 3 times before having to recharge the Power Bank. The only reason I am giving it "only" 4 stars is Because The cable Which was delivered with the device which defect. I tested it on another device but it did not work on did either. But This should not be a reason for not buying this product.