I have an EV. The AC charging cable is thick and heavy and about 5 metres long. When I’ve finished using it, I roll it up into loops of about 1 foot diameter and stow it in a pocket in the side of the trunk.
Here’s the thing: I often partially uncoil it for use, and (seemingly) every time I try to roll it up again I do it “wrong”. By “wrong” I mean that each loop I add introduces a half-twist in the cable which accumulates until I have to give up and unroll the cable completely before coiling it successfully and stowing it ready for its next use.
Two things frustrate me: 1) I can’t seem to tell which way is “wrong” and 2) I feel if I don’t know and just start coiling it should be wrong 50% of the time but instead I seem to get it wrong 100% of the time and I’ve no idea why (and I have a doctorate in engineering).
By partially uncoil it, what I mean is that I take the fully coiled cable, unroll one end enough to connect to the car, unroll the other end enough to plug into the charge point, and leave the remainder rolled as it was stored.
Yes I know it’s probably good practice to uncoil a cable completely when passing 32A through it but I have my reasons so let’s not focus on that aspect of the story.
You may have to coil it the same way a few times to get the cable to naturally take the same shape. When you coil it, always start on the same end (say, the end that plugs into the car), and remember whether the first coil is over or under. Maybe use a mnemonic or whatever to remember. Eventually it will coil naturally.
Obviously you need to start with a cable that has no twists in it already. Lay it out on the ground and let it relax. Maybe dangle it from a high point if you have a place available.
I use long cables frequently.
For a couple of them I attached a little helper.
I glued a Velcro cable wrap at the point where I want the loop size to be. I make the first loop so the connector is at the cable wrap. Snug the cable wrap so that the head will stay in place. Then I can rotate the loop and gather in the cable. It works as if the cable is now on a reel.
You may have to attach something near the connector if cable is slipping through the wrap to easily. But it works nicely so far.
Now that I described my trick, I thought of another thing. I will glue another longer wrap near the connector. That will keep the other one from sliding and then be used to wrap the completed coil. Instead of always losing it.
Over-under for the win. It is a revelation. When I heard of it and tried it, probably only ten years ago, it was a “where have you been all my life” moment.
What it does, in effect, is put opposite twists into the cable with every second turn. Meaning that they net to zero and you don’t end up with something that wants to turn itself into a knotted mess.
I have been coiling my guitar cables with over/under for years and am a strong proponent of it.
But mind the cable ends, otherwise bad things happen!
On an annoyingly regular basis, I go to grab cables while setting up my bass and find myself holding a long neatly untwisted cable with a series of overhand knots in it.
It’s remarkably easy to coil a cable in the reel style, but uncoil it by pulling loops off from the side. The result of which is to build in a set of twists during uncoiling that weren’t there while it was fully coiled. But which then need to be fought with during coiling. Leaving one with the feeling that “I left it neatly coiled last time, why is it fighting me now?” every time.
I learned the “butterfly” method when coiling paper punch tape in one hand waaay back when.
The over-under is basically the same thing, geometrically.
Another variant is to loop around your elbow and hand as shown in the video except to make a figure 8 pattern instead of a straight circle. I’ll also do a figure 8 sometimes for fat things like hoses, making the figure on the ground. (Sloppy, but quick and makes pulling the hose out later simple.)
When you have very long and thick cables, or e.g., garden hoses that you don’t store on a reel, a figure-eight pattern keeps them from getting twisted. I first saw that used for the big studio camera cables at a TV station where I interned in the early 1970s. In both these examples, they are stored lying on the floor.
This is the only reply so far that addresses the question I intended to ask. I do appreciate all the excellent advice about coiling techniques, and I fully accept the failure of communication is my own fault, mainly for choosing a thread title that invites answers to a different question.
I’ll try this:
Imagine you have a thick cable, about 5 metres long, coiled in loops of diameter 30-50 cm. It is relaxed (not twisted). You uncoil about 1.5 metres of cable at one end and connect that end to a socket.
Later you disconnect it and attempt to return it to its previous configuration. You hold the coil and start to loop it back up. But invariably you find it resists being coiled in the direction you are coiling it. You have to either make several “untwisting” adjustments, or give up and lay the whole thing out straight and coil it up.
What is going on?
Is there a technique that would allow me to recoil the partially uncoiled cable successfully?
Is there a 50-50 chance of getting it right?
If it’s coiled, then it’s twisted. The only question is if it’s coiled in a way such that the twists cancel out on average (over-under, etc.) or if they are additive (“standard” coiling).
I guess it sorta doesn’t matter for your specific example, because 50 cm diameter and 1.5 m length is just a single coil. If you always coil the same way, it seems like it shouldn’t be too difficult to match whatever it had been. It definitely shouldn’t require “several” untwistings since there’s just one to start with.
You’re right - my description from memory was inaccurate in a number of respects. I just went out and did some measuring.
The full length of cable is 6m, and it’s coiled in 9 loops (+/-0.5). Each loop is about 20-25 cm diameter and the whole assembly is about 28 cm diameter.
What I meant by saying it’s relaxed (not twisted) is that it’s twisted the right amount (0.5 twists per loop) so that it has no tendency to untwist. Poor choice of terminology on my part.
When I partially uncoil, the uncoiled length is about 4 loops or about 2.5m.
Here’s the thing: I was not able to replicate the problem. I tried it twice just now, and on both occasions I wound it back up easily and it didn’t fight back. So I don’t know anymore.
That seems like a pretty tight coil, though I guess your constraint is fitting it in the pocket.
If you aren’t having problems, then so be it. But if you are taking off 4 loops, then I would learn to coil that via two over-unders. It takes no more time than to do it the typical way and is much faster to uncoil, not to mention lowering the risk of it getting tangled with itself.
