Hello, new-ish Arduino user here. I have a dilemma involving the best practice to power a set of 6 9g microservos (you know exactly the ones).
My solution was to purchase a 15k mah battery bank, with two usb outputs. Each output on the USB is rated for 5v, 2.1 amp.
I broke the servos into sets of three, and using scrap USB cables, split the end into three positive and three negative connections. I connected them into the servos, and then each servo signal pin into the Arduino Mega that runs the show.
I also have a ground pin running from each usb cable to the arduino ground.
I have a simple self locking switch on a separate pin to alert the board to send signal to the servos to start a predefined function of motions.
The battery bank should automatically draw power when the servos "ask", as the battery bank came with an auto charge function that detects a device requesting current.
My main issue is this: When I connect one usb plug into one of the outputs, everything works fine. The three motors turn as they should. But upon plugging in the second, the battery bank stutters, and dies. I am at a loss as to what I'm missing except perhaps that 5v 2.1 amp isnt enough for three servos in parallel. Any advice would be great!