Replacing or Upgrading Hub Motor Wires

October 27, 2012
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This is the first in our series of ebike repair stories. Also, replacing the wires going into your motor is a great first step in hotrodding your hub motor since burned wires is the #1 reason for failure in an overvolted overwatted hub motor. (read our hotrodding hub motor story).

For an example how effective such a motor can be, one builder/racer modified his $100 9C motor by upgrading to thicker wires and was the first electric bicycle to finish Pikes Peak in 2012, finishing ahead of a team of $15,000 Optibikes. (read his inspiring story)  The motor in the pictures is the same 9C motor this builder used to win Pikes. In any case, upgrading or repairing the wires going into a hub motor is not an easy task, and this step-by-step pictorial guide should make it easier for you.

One common issue with hub motors is broken or shorted wires at the point where the wires exit the motor axle. If the wires are tugged or twisted the sharp edges of the hub motor axle can cut through the wire insulation or completely sever the wires. Most hub motors employ hall sensors to tell the controller the motor position. Hall sensors are easily burnt out if the signal wires short to power or ground. The motor shown below stopped functioning after the wires were damaged. A quick test showed that the hall sensors were burnt out. (Testing Hall sensors article to come).

 

 

To read the rest of this extensive  story go here  to our repair section.

 

Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.

12 Comments

  1. Great article! I love tech how-tos. I would REALLY like to see how a hub motor can be converted to a mid drive motor as on Simon Howarth’s Super-Charged Racer. Swapping the roles of stator and armature are puzzling to me, especially regarding the wiring. Using a cheap hub motor over volted on a mid drive sounds perfect to me. I think Simon nailed it.

    • Thanks for the comment, Michael. Using a hub motor as a non-hub would add a huge amount of torque, and since it creates a lot of copper mass, it will tolerate many more watts than the current factory non-hub bikes. Here’s a thread about doing that: http://endless-sphere.com/forums/viewtopic.php?f=6&t=38553

    • From Spinningmagnets: Thanks for the comment, Michael. Using a hub motor as a non-hub would add a huge amount of torque, and since it creates a lot of copper mass, it will tolerate many more watts than the current factory non-hub bikes. Here’s a thread about doing that: http://endless-sphere.com/forums/viewtopic.php?f=6&t=38553

  2. You should never ever crimp a previously soldered wire!

  3. Has anyone tried putting a commutator on a hub motor to make it run like a conventional brushed DC motor? It seems that would be better for a mid drive setup.

  4. Actually you get cheap 35A controllers from China that run sensor OR sensorless hub motors for as little as 25-30 bucks. Shure they are no Lyen but they work fine up to 60 volt. Google: ‘KU123 Controller’.

    • I will take a look at the cheap sensorless controllers. Thanks for the link.

  5. Thanks for your website, very interesting (and sorry for my poor english).

    Well, in this article, I think technical information is missing. I would like to read the size of wires before and after, the temperature you can reach before and after… I mean upgrading is for better performances, so what is the start point and where can you go with the upgrade ?

    Anyway thanks again for your very nice website.

  6. MY bike is starting vybration and slowly or not working ,why?

    • same here, maybe at high speed you crossed from a

      bump or a hole and you broke the motor hub, that happened to me and now im looking how to fix it

  7. why don’t any ebike manufacturers sell casings it’s driving me friggin crazy, like trying to find gold-dust looking everywhere for 9c hub casings

    • try looking for RPE, they do moter and battery for ebikes

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