I'm using the iphone5S. I need to press the power button. (Plugs in > charges > then stop charging after 2 seconds > press power again > start charging)

The xiaomi charger did not have any issues charging my iphone(as long as it's battery is not flat) or my Redmi note.
But I always can't seem to get it to power up and charge my iphone.

At first I thought it was the cable, but I tested this out with orginal apple cables and certified belkin cables. Same issue.

This happened to me several times but it does not occur for my eneloops.

Hmm...
It goes like
Flat > battery bank plugged in > charging > switches on > stop charging while starting up > phone goes back to flat without switching on.

I'm actually pretty happy with the 5s. Not too large and more than sufficient speed. But battery life is horrible after 1.5 years of usage. Regretted not swapping it for another refurbished right after the one year warranty was up.