The centre stack is an often used area to store small items and connect them with the 9 volt outlet.
The problem of wires within cars is that the wires are among 1 meter long, but you mostly need about 15 cm of length in your car. That means that you have 85 cm too much.
I designed this simple concept for all the wires in the centre stack of the car. At the top of this storage area a small elastic net is placed where you can just dump your excess wires into. The bottom area of the storage area stays clear for other items.