I was working on an Arduino project and when I finished it I said “well it’d be cool to power it with a USB powerbank and put it outside”.
I did that. I connected the Arduino to the powerbank and it worked!
But after about 20 seconds the Arduino powered off.
Well, the powerbank turned off. And along with it the Arduino.
Turned out the Arduino didn’t consume enough power to be noticeable by the powerbank that thought nothing was connected and it was just wasting its cycles.
I found some solutions to the problem, involving making the Arduino consume more power. Like https://www.instructables.com/USB-External-Battery-Packs-on-Arduino-turns-OFF/.
Or getting a powerbank that didn’t turn off automatically.
In my case I decided to go with a rechargeable battery instead, since I was working with an Arduino MKR 1010 WiFi and it had a 3.7V Li-Po battery option.