Hi guys this is my first post here. I just like to ask you guys what do you use to power your arduino robot. Im using 2 pcs of power bank rated 4400mah i connected them just like on the diagram below total voltage is 10v just enough to power my arduino and 2DC motors driven by L293D. What do you think experts?? Ive been using them for months and no problem yet.
Hello mate
The way you are connecting your power in good, but you can make it better.
if you are not using a motor controller shield then keep powering your project this way. However, if you want to use a motor shield (photo is attached) then you can save your self some wires by only powering up the shield and the Arduino will be powered by the shield (Arduino boards need small currents)
saving two wires might sound silly, I mean its not that much, but trust me I made a mistake wiring a 9V DIRECTLY TO MY ARDUINO BOARD, I was wiring two motors a Bluetooth module and Leds, the 9V was supposed to go to the motor shield which will power everything, lucky no Arduino boards where injured during that test 
Thanks im not using motor shield im using L293D chip with personalized pcb 
but how about using different ampere rating for example 4400 mah and 5000mah do you think there will be no problem if i connect it the same way? Sorry for the very noob question i just dont want to fry my boards 