Hello!
I just got my first external battery from Anker.
The model is power core speed 20000 PD and I am inlove with it… the charge speed is insane !
The battery beats the original chargers for my Samsung note 9 and S8+ 
The problem is that the original Samsung chargers can’t charge the battery fast. The battery is charging insane slow! (Arround 50% for more than 12 hours)
So… I found one Hama charger (PD charger with type c 27w 3A) and the battery got recharged super fast. The charger is not expensive and I’m worried about battery life.
So my question is … Is it Safe ?
P.s. my battery don’t have an adapter in the package (this is normal… I got only type-c to type-c cable)
the PowerCore will be fine