This mod was done on the USRA 0-6-0 tether but it should work for most tethers I would think. @gunrunnerjohn came up with it and @RickO asked for a tutorial so here it is. I think it looks more like a water hose with this sleeve added.
First, you'll need to unplug the tender and flip it upside down gently. Then remove the four corner screws. They're located where the red circles are:
Buy yourself some quarter inch expandable sleeving. You can use 2837K72 from McMasterCarr. Cut it to 3.5" long. You might be able to go shorter here. You'll have to experiment. Now take a torch lighter and melt one end so it doesn't come apart on you. Go slow here. If you go too fast, you'll just burn it or melt it unevenly. It took me a few minutes to get it. You can push the ends of the sleeve together to get it to expand. If you melted one end correctly, it should look like this:
Now you'll need to make the plug at the end of the tether able to fit in there. So grab it like this:
It's tricky but you'll need to expand the sleeve and get that plug into the sleeve at the same time. Having someone else help would be the easier way but I did it myself by trying for 10 minutes so you can do it on your own if you're ambitious.
Now you gotta move it like an inch worm. Push the sleeve together to expand it, move the plug further in, and repeat until you're at the end. Like the following sequence here:
You'll have to carefully and slowly work the plug through the melted end. You might break the melted sections and that's ok. You can very carefully touch it up when you're done. The unmelted end can also be melted at this point but I only did a little bit.
I might go back and shorten the sleeve a bit so it stays a bit more collapsed. I also would consider trying a smaller sleeve but I would worry I couldn't get the plug through. Maybe @gunrunnerjohn will have some tips and tricks I didn't think of. This surely isn't a perfect attempt but it sure looks better than all those wires flailing about. It also seems to put a little forward pressure on the plug but I haven't ran enough to see if that's true. This is an awesome product they put out and this little addition is cheap and easy.