Does charging iPhone 6 continuously with power bank can decrease battery life?

Does charging iPhone 6 continuously with power bank can decrease battery life? - 1

It's a myth. The only thing that reduces the life span of a battery is charging cycles (from low battery to 100%). The more the charging cycles, the less energy the battery will retain, until the battery is almost dead and doesn't hold charge. Some battery apps tell you the charging cycles, designed capacity and actual capacity.

For example I had a 4s which I didn't replace the battery from day 1 to 2.5 years later and it would only retain about 70% of its designed capacity because it was well over 900 charging cycles. So even if the phone says 100% it was actually 70% of what it had on day 1.

Nope I don't think so, but you must use the branded one and if you need some advanced security, Leo Privacy