We have enough rechargeable devices that we needed a way to charge them that was less chaotic, that didn’t leave devices on the floor. I looked at commercially available options, but nothing seemed to do what I want. So I started constructing my own wall mounting approach.
My idea was to have a shallow shelf that devices rest on, with some mechanism to hold and organize the cables and a box to hold the charger hub. I thought initially that cables could rest in slots that were narrow enough so that the plug wouldn’t fall through:

Cables can slip into the skinny slot to hold them in place. The wider part of the slot permits the cable end to stick down when a device is charging.
This approach didn’t work because the cables sometimes pull forward out of the slots. The next idea was to use rubber to hold the cables in place. But which type of rubber? McMaster has an overwhelming number of options, both types of rubber, thicknesses, and hardnesses. I tested several options:
It seemed like the 1/32″ EPDM with a Shore hardness of 40A was promising. So the prototype looks like this:
I realized that velcro alone did not suffice to manage the cables, so I added the cable wrapping posts. Also it seemed like the EPDM rubber was not holding cables as well as I expected, especially with thicker cables. So I tried a change in the design with a thicker piece of rubber and a hole to hold the cable. This seems to work better at holding cables, though it is more difficult to get them in and out.

The black rubber has a hole punched in it to hold the cable. This does seem to be more secure, though choosing the right rubber is still an issue.
We’ve had this in use for a while now, but one problem I’ve noticed is that the users don’t like to leave the cables secured in the rubber slots. They prefer to just leave them dangling. Does this mean the rubber slots are unnecessary?
How can this design be improved?