Wiring hub dynamo

[Philip Benstead]

Wiring hub dynamo
I had to wire up the hub dynamo, I used five-strand cables that came with the front light.

I had to insert the cables into the Dynamo Bike Hub Connector Kit SP
https://www.ebay.co.uk/itm/256364258882 ... 0yEALw_wcB

Even though I twisted the 5-strand cable, the cable kept bending or unravelling when installing.

I found it difficult and time-consuming,

Question

Any view on using a double-core single-strand cable like this, say size 1 or 1.5 mm?
https://www.alibaba.com/product-detail/ ... 25093.html


So, using two separate cables I need to use a cable cover for protection.

PVC Cable Sleeving Black All Sizes Electrical Cable Tubing Earth Harness

https://www.ebay.co.uk/itm/354616857623 ... RTEALw_wcB

[Brucey]

because all wires on a bike must be allowed to flex, you really want more strands, not fewer. You should be able to wire up many of these plugs more easily by ensuring that the insides of the plug are flash-free before you start.

[freiston]

I'm not sure if I'm understanding the issue, but wouldn't sheathing two separate insulated wires be difficult and time consuming too (not to mention the faff in getting all the stuff to be a "good fit"). Couldn't you use solder and an iron to tin the bare ends of the five-strand instead of using single core wire? If you mean the cable length was unwieldy when trying to install, could you temporarily tape it (or even blu-tack it) into place to hold it steady?

[cycle tramp]

Deleted

[PH]

I usually strip a bit more than needed, pull it through and trim the excess, that way it doesn't matter that the ends become untidy, they're being discarded.

[slowster]

My tip with two core (bell wire type) cable, e.g. as fitted to B&M lights, is

1. Separate the two covered cores for 20mm-30mm using a pen knife.
2. Cut through the insulation around each core about 10mm from the end. Do this by rotating the wire on a suitable cutting surface as you cut it with a blade.
3. To remove the 10mm of insulation, simultaneously twist it while also slowly pulling it off.

This will give a much better twist to the strands than twisting them after the insulation has been pulled off, and make it a bit easier to insert the twisted strands into the the holes in the connector brick and then fold them back on themselves into the two slots which hold the stands against the hub's spade conectors.

[Mick F]

I ran my hub dynamo cabe up the inside of the fork blade.
Breather holes top and bottom, and I threaded a length of doubled-up nylon fishing line down from top to bottom, then pulled the co-ax cable up. I twisted the end of the cable over the doubled-up line to attach it, and pulled.

Neat, and hidden.

[rjb]

I ran my hub dynamo cabe up the inside of the fork blade.
Breather holes top and bottom, and I threaded a length of doubled-up nylon fishing line down from top to bottom, then pulled the co-ax cable up. I twisted the end of the cable over the doubled-up line to attach it, and pulled.

Neat, and hidden.

The difficult bit would be persuading the line out of the lower breather hole. Putting a loop of wire inside from outside could enable one to pull the line out. BTW How did you do it.

[gregoryoftours]

The insulation doesn't want to go too far inside the plug or it will interfere with the contact tab on the dynamo that the plug fits to.

Is the bit you had trouble with poking the wires through the two holes without them catching, like the second step in these photos?

It can be fiddly but twisting the strands helps, and like Brucey said ensuring that the holes are clear and unobstructed. Solid core wire would be easier to thread but it's not suitable. It is stiff and will break over time because it's not flexible enough.

Did you manage to get it done ok in the end anyway despite it being a faff?

For what is worth, I wouldn't worry too much about cable covers etc, the plug itself isn't designed to be waterproof and water gets in between the plug and the tab it fits onto anyway. The best thing to do is put contact spray/other suitable substance on it so that it doesn't corrode. Current is not high enough for the presence of water to create electrical problems. I think that I'm right in this but would be interested to hear other opinions. In any case I've only had problems with corrosion but not the presence of water itself.

[Philip Benstead]

Many thanks, that is what I needed. I have been doing it wrong.

Thanks again

The insulation doesn't want to go too far inside the plug or it will interfere with the contact tab on the dynamo that the plug fits to.IMG_20240203_170710.jpgIMG_20240203_170748.jpgIMG_20240203_170814.jpgIMG_20240203_170839.jpgIMG_20240203_172157.jpg

Is the bit you had trouble with poking the wires through the two holes without them catching, like the second step in these photos?

It can be fiddly but twisting the strands helps, and like Brucey said ensuring that the holes are clear and unobstructed. Solid core wire would be easier to thread but it's not suitable. It is stiff and will break over time because it's not flexible enough.

Did you manage to get it done ok in the end anyway despite it being a faff?

For what is worth, I wouldn't worry too much about cable covers etc, the plug itself isn't designed to be waterproof and water gets in between the plug and the tab it fits onto anyway. The best thing to do is put contact spray/other suitable substance on it so that it doesn't corrode. Current is not high enough for the presence of water to create electrical problems. I think that I'm right in this but would be interested to hear other opinions. In any case I've only had problems with corrosion but not the presence of water itself.

[Brucey]

I too have had corrosion rather than water problems per se. I just did what I usually do, which is to coat everything in waxoyl &/or vaseline. Tinning the wires is rightly frowned upon by some, but I'd far sooner deal with that when it has gone bad than frayed wires. I ran for a long time without the outer part of the two-piece plug. figuring out that it would be much easier to re-make the connections by the roadside should the need arise (which it never did, in fact). Nonetheless, I was ready should the need arise, and the connection was still sound enough, even with half the plug missing. Clearly someone else agrees with this line of thought (or maybe it's just cheaper) because you only get a one-piece plug with a SA hub.

[Brucey]

.......Many thanks, that is what I needed. I have been doing it wrong......

note also that I have found that the moulding flash inside some plugs is so bad it can make normal wiring impossible. Should it be the case, it is easy enough to recrify this beforehand eg. using a small screwdriver.

[Philip Benstead]

Tinning wires

https://www.google.com/search?newwindow ... We0io,st:0


Question

What is the downside to tinning?

[gregoryoftours]

The downside to tinning is that any bending/flexing that happens will be concentrated in the spot where the tinning ends. This may cause the strands at that point to fatigue and break earlier than they would have done otherwise. It should be ok if the wire is strain relieved past the point where the tinned strands become separate strands.

Eg similar but not the same is cable strain relief where a flex is clamped where it enters a mains plug, so that the individual wires going to the live, neutral and earth are protected from flexing and bending.

[Mick F]

I ran my hub dynamo cabe up the inside of the fork blade.
Breather holes top and bottom, and I threaded a length of doubled-up nylon fishing line down from top to bottom, then pulled the co-ax cable up. I twisted the end of the cable over the doubled-up line to attach it, and pulled.

Neat, and hidden.

The difficult bit would be persuading the line out of the lower breather hole. Putting a loop of wire inside from outside could enable one to pull the line out. BTW How did you do it.

I used a loop of thin fishing line threaded down from the bottom up ......... if my memory serves me correctly.
I 'fished" the loop out, and then twisted the ends of the wiring together through the loop and pulled it all through.

My wiring is thin flexible co-ax.

There's a thread on here about it somewhere and Brucey - among others - were instrumental in giving me the ideas to do it.
I'm off out cycling in half an hour so I don't have time to look it up and put a link to it at the moment.