Hi again,
my 2A powerbank arrived, hooked it up and ... .... nothing 
I've contacted a local (almost 50km away from me) school that gives arduino classes ... I explained them in an email, what the problem is, what I would like to achieve. Maybe they can give me a start to where to begin with, as I ran out of ideas and posibilites right now.
I'll let you know if I get somewhere with this.
Thanks to all those of you who have replied and tried to help me out.
Now I know where to go to, when I want to give a go on another project.