where can i find this cable to the hub motor?

Lightweight / Folding / Portable EVs - seats optional
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tung256
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where can i find this cable to the hub motor?

Post by tung256 » Dec 29, 2017 11:02 pm

recently my etwow scooter has been acting up. i've finally pin point it to a cable that has been cut due to stress.
all photos are here and you can see the cut wire
https://imgur.com/a/C2Giv

should i just solder the cut wire in yellow? would the solder be strong enough?
or should i just get the cable replacement from ebay? what is it called?
one end of the cable is female with 9 pin, but only 8 wire is actually used. the yellow, green, and blue are really thick. because the yellow is cut, the scooter can sometimes slow down or jerk around.
pls help, thanks!

aroundqube
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Re: where can i find this cable to the hub motor?

Post by aroundqube » Dec 30, 2017 12:27 am


tung256
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Re: where can i find this cable to the hub motor?

Post by tung256 » Jan 04, 2018 10:04 am

thanks!
i finally found one on aliexpress for $13 shipped to my house.
for now, i have the wire soldered back as temp.

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fechter
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Re: where can i find this cable to the hub motor?

Post by fechter » Jan 04, 2018 10:19 am

If you cut away the plastic around the broken wire and can get a good solder joint, it should work OK. Tape it up well so the joint doesn't move. It's also helpful to see if there was an issue with the wire routing that caused it to break in the first place.
"One test is worth a thousand opinions"

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teklektik
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Re: where can i find this cable to the hub motor?

Post by teklektik » Jan 04, 2018 12:12 pm

Looking at the bike bits in the background, it appears the connector is floating in a point of high motion. Ideally you want the cable on both sides of the connector tied to a frame component where they're not moving at all.

The issue arose because of the absence of an adequate strain relief at the transition from the inflexible connector body to the flexible cable. This led to stress at the point of discontinuity - right where the cable meets the body.

If you are stuck with a floating mount like this, sleeve the body and cable with two or three layers of increasingly long heat shrink. Start with a short piece (5/8-3/4") then layer on slightly longer pieces so the cable/sleeve becomes increasingly flexible as you move away from the connector. This will distribute the stress harmlessly over a longer length of cable (maybe 2"). This is the identical gimmick that you see on wall warts, power tool cords, etc where the cord leaves the device.

If you do fechter's fix above and sleeve the result like this, it should last longer than you'll own the bike...

connectorHighStressPoint.png
connectorHighStressPoint.png (85.25 KiB) Viewed 113 times

heatShrinkStrainRelief.png
Sleeve with heatshrink so flexibility changes more slowly
heatShrinkStrainRelief.png (1.57 KiB) Viewed 113 times

If you don't have shrink on hand, a less tidy but fair second best is self-fusing silicone tape or self-fusing rubber tape available at your local Home Depot or Harbor Freight ('Stretch and Seal' or 'Self Bonding Super Tape') - just be sure to get a 'tapered thickness' application.
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MrDude_1
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Re: where can i find this cable to the hub motor?

Post by MrDude_1 » Jan 04, 2018 1:31 pm

teklektik is correct about the lack of strain relief. If you use marine heatshrink it has hot glue inside so you dont need as many layers... although the best way I have found is to put some hotglue in there for strain relief, let it cool enough, then put heatshrink on, and heat the whole thing with a heatgun so that the hotglue softens and heatshrink tightens it all together, making a clean, neat strain relief.
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tung256
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Re: where can i find this cable to the hub motor?

Post by tung256 » Jan 07, 2018 8:50 am

wow! very helpful guys. thank you!
i was able to solder on. what a relief i dont have to buy a cable. now onto the heat shrink.

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