* Make sure you are charging and withdrawing power with a good quality cable and a good power supply. NEVER charge a power bank with a rapid charge power supply unless specifically stated in the manual. A 1 amp or computer USB outlet is fine.
* The power bank should be warm when charging, not stone cold, and definitely not toasting hot.
* As of September 2020, some phones may have updates that make charging with some power banks tedious or impossible. These updates are designed to protect the phone from cheap power banks that shouldn’t be on the market. If you can, buy from a reputable brand that specifically states it can work with the latest phones. It’ll cost more, but you’ll have piece of mind knowing that your phone battery will charge and is not stressed by inconsistent draw.