Im intrigued about this too, I have the M8 and my father has a Galaxy S5. My thought is when we go to a race and dont have our chargers we could just plug into the bank and boom charged. could be a good addition to a battery bank but even better is to incorporate it into a battery case like a Mophie case. Then you could use your phone( games maybe or surfing the web etc while charging instead of sitting at a %) and juice up the battery. Still waiting for Mophie to make case for the M8, hopefully.