How long should this take?

tirespider

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Dec 5, 2018
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The bottpm-line question is, would a professional with the right tools need two and a half hours to reach the conclusion that a hub motor does in fact work?  Just how long does it take to try every combination of wires? 

This is the full entry logs for the work done by the ebike shop (with in-house techs) I used. I wanted them to diagnose my hub motor and see why it wasn't working. Now, where I come from $80 an hour is a lot of money but I'm willing to pay it if the time is well spent. So the question I have is, where you come from (the ebike world), does anything seem unreasonable or unlikely about a circumstance where this amount of time is required for this effort? Is this the typical amount of time it would take any ebike professional tech to accomplish this? Is "2.5 hours" or "two half hours" closer to what you'd expect?

November 15, 2018 - Customer brought in a rear wheel hub motor, battery, controller and throttle, parts from 24V X-treme eMtb, off of bike frame (bought 2 years ago). Throttle is not original or from X-treme, customer thinks battery and throttle are okay. Please diagnose.

November 26, 2018 - Technician MC connected up motor, controller, throttle and 24V surrogate batteries - does not work. Tested motor with Lenz law and tested okay. Li battery is sitting at 28.5V, unable to load test. Negative battery lead on controller is worn, possibly damaged. Throttle wires have been cut and repaired, and have tape around them. Is 3 pin throttle; do not have another 24V 3 pin throttle to test. Tried connecting 3 of 7 pins from another throttle but does not work. Recommend replacing controller and throttle. 2.5+ hrs.

(the rest is parts, 1 controller and 1 throttle.)

Is this reasonable or excessive time?
 
First test is to check voltage on the battery leads (where it connects to the controller) with a digital multi-meter. Second test is to swap-in a separate "verified to work" throttle of the same type to verify it is not the throttle. Not because it is "likely" but because it is a fast and easy test.

Third test is to swap-in a sensorless controller (small 6-FET) to verify that the motor phases work fine. (if it spins, but it is going backwards, swap the Green/Yellow phase wires) Again, fast and easy.

If the motor spins correctly with a sensorless controller, it is not the:

battery
throttle
motor phases

So, it "could be" the controller, or the Hall sensors, or Hall sensor wires.

Can this be done in ten minutes? even less, my friend...

A useful diagnostic tool is to have a myriad of connection adapters. Concerning the Halls, there is a black and red power wire-set, and then three signal wires which "should be" Blue/Green/Yellow, B/G/Y (alphabetical order).

The three phase wires have six possible combinations (BGY, BYG, GBY, GYB, YBG, YGB). The three Hall sensor wires have the same number of possible combinations. 6 X 6 = 36 possible combinations. A handful will rotate the motor in the forward direction, a couple of those will be "noisy" and one of the remaining combos will have a very low amp-draw when unloaded.

Print-out a list of all 36 combinations, and cross off any that rotate backwards, don't rotate, or rotate forwards slowly with high noise. Put an in-line watt-meter on the battery to test the amp-draw for the remaining combos.

Sit down, open beer, drink. (or coffee, if it's before 12:00...). I "may have" gotten some part of this wrong, if so...I blame the beer.
 
troubleshoot including replace controller and throttle 2.5hr sorta reasonable

especially if custom/restorative wiring connections involved

2.5hr troubleshooting only not reasonable imo
 
It will cost $200 for labor to get your old motor equipped with a working throttle/cobtroller plus probably $75-100 for those parts?

You can buy a complete geared hubmotor kit that includes motor/wheel, controller, PAS sensor, throttle, LED display, and torque arm for under $200. Install it yourself. After all, you took the other one off. In your spare time you can verify the old motor works and build a 2nd ebike later.

I think the labor hours are reasonable to do a new controller/throttle. The rate is high though, given it's just a dorky ebike.
 
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