steve.vSteve,
Just curious what type of phone do you have? What mAh battery is it using and what specific powerbanks are you talking about that could charge today's smartphones 15 times? I have a Sony Z5 Premium and have tried many different powerbanks including this one and none of them would even get close to charge my phone up to 15 times.
Most phones today have around a 3000mAh battery. Without going into discussion about loss of power from the powerbank during the charge and quality of batteries. Lets say you have the absolute perfect powerbank with perfect batteries and zero power loss during the charge. You would still need a powerbank with around 45,000-50,000mAh to charge a phone with a 3000mAh battery 15 times.
Cheers.
Tex-Arozzidefinitely agree, i got one of those cheap Kmashi power banks and the 10000 mah version only charges my lg v10 once. i dont know how good this power bank is, but i definitely find it hard to believe there is a reasonably portable power bank that can charge a "modern" smartphone more than 5 times, let alone 15