I currently have a 50,000 mAH USB power bank powering my Arduino Uno and micro servomotor. Unfortunately, my power bank has an automatic shutoff and shuts off after 2 hrs of runtime (I need 16 hrs for my project). I can restart the power bank by hitting the on button and it will run just fine for another 1-2 hrs at which point it will shut off. In one instance, the power bank ran for the desired 16 hrs straight hours. I believe that my arduino/servo are very close to the current threshold of the bank which could explain some of the variability I am seeing in terms of turn-off time. Would hooking up a resistor in the circuit do the trick and if so where?
Not quite sure about the brand of power bank (just one I found off Ebay). I believe the arduino uno and servo consume about 60 mA for power.