My powerbank is connected to UNO via its 5.0V/GND pins which manage display, sonic sensor, pad and led. All work fine.
In paralel this battery can power another microcontroller via its 5.0V/GND pins too but I noticed 2 problems:
If the second microcontroller is an Uno, Mega or Pro Micro (5V) that's ok, but when I try with an ATtiny85 (Digispark) or a Nano (5V) it's like if there's not enough power... Nothing start, leds indicator are very dark. However my powerbank can deliver 2A. Thats strange!
When I unplug the 2nd device in parallel (it could be just a led, not necesseray a microcontroller), the first microcontroller resets. It's like if the powerbank restarts when it detects a variation of current. An idea?