are you sure with only charging with powerbank will fry your phone motherboard? how about normal ac charger?

there is a built in circuit to limit the current on phone motherboard. i had tried using 5V 3A charger to change my phone. when i measure, it only accept the current upto 1.1-1.2A and not 3A.

there are also built in circuit for powerbank itself, that's why it will have 2 output : 1A and 2.1A.
the rating is showing the max current that it allow, not must be exactly 1A.

so far i tried my times for overnight charging no problem on my phone. i like the feature that it will auto cut off when my phone is fully charged.