Help with Impulse Evo RS Mid drive motor

kosio86

10 mW
Joined
May 22, 2015
Messages
20
Hi my ebike is out of warranty now and started doing some crazy stuff. It sometimes loses power and sometimes stops supporting at all. The problem goes away after restarting the system . I got once the following Message on the screen: "Hint 1/1: Wait for Drive". It feels as if the torque sensor is not acting correctly- sometimes I have to press really hard on the pedals, for the support to kick in. I searched all the forums and saw that there are many occurrences of that issue and all are resolved by replacing the motor under warranty. I, however don't have warranty anymore and there is no dealer in my country I can check with, so I decided to check it myself. I opened the motor, carefully, which was very easy (in comparison to the BionX hub motor I opened in the past). Although the bad reviews of the reliability of the motor it looks really well built and very serviceable Although I cannot source any spare parts for it.
I checked all the wires with multimeter for disruptions, checked for visible damage on chips, capacitors, sensors and mechanical parts and none is visible. Torque sensor looks intact and very heavy duty (in comparison with the one I had on my old BionX ebike).
I am out of ideas. I can provide pictures of the internals if anyone is interested in that. I am looking for some dealer or person who might now the model and its problems and point me in the right direction.
It is early 2016 motor 250w 25km/h limit-never abused and only 2500km old.
 
Today I noticed that the cadance reading shows 0 on the display, and just somtimes (5% of the time I am pedaling) jumps to 60-90 and then drops back to 0. That is definately not normal. Interesting is that assistance is still working while 0 and cut offs don't seem directly related to the cadance value. Speedometer on the back wheel works fine.
 
Hi can u send instructions how to get to motot hardness. I'm installing speedbox.
 
Two years later the bike is still working and still acting up occasionally:
It is 2500km now and it's still running and is in pristine condition-bike parts are great and rides great downhill, battery is still 100% healthy and has great range, motor is mechanically looking great-no broken freewheel paws, no bad bearings, no water ingress, gears are not stripped etc. The problem that I cannot resolve is with the power delivery. For the last 700km you have to press hard in order to get going and keep low cadance and pressure on the pedals to get good power from the bike. The power delivery bar (it has one) rarely goes over the middle, in the past it reached the top at steep hills. So, I am not a total electronics noob, but the logic board of the motor is way over my level of expertise. It looks very well made but it is full with tiny components that are lacquered for water proofing and it is imposible for me to check any components, besides the 2 capacitors, which seem in pristine condition (measured with an ESR meter).
The torque sensor is some proprietary make of Derby Darum company and no way to source a replacemnt. It is a cylindrical one placed between the cranks' axle and the freewheel that engages to the main big metal gear. It has three wires- White, Brown and Green. When removed I can only read resistance between leads-15,5ohm WtoB;15,5ohm WtoG;30ohm BtoG. When powered on it reads White-7.36v over COM, Brown and Green read 7.26v over COM. I cannot find an easy way to stress it and still measure it while poweres, but I can't see how it could be broken. There is not a lot to break there. The other sensor is a small gear speed magnetic sensor, on the Main big metal gear that basically should read the forward rpms of the cranks, after the freewheel. It also has 4 pins. Both middle ones are ground. Left one is power-3.78v when bike is on. Right pin is Output which reads 3.3v, or 0v, depending on whether there is a gear tooth nearby. This is the sensor I suspect, because it seems to be the cadance sensor an I have intermittent 0 readings of the cadance counter on the diaplay.
So, I want to fix the bike since ever, bit since it is this closed system without any support in my country I am now thinking of bypassing its controller and use an external one. I was planning of using a cheap Chinese sensorless one, as there are no hall sensors on the motor at all and use a thumb trottle plus keeping the original board for communicating to the battery, so that I don't need to swap the BMS, but I am still hoping that someone tech-savy could assist with troubleshooting the sensors. I just feel very bad when a quality item costing thousands of dollars has to be thrown away because of 10$ sensor. Totally not eco-friendly.
 

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Hi, I have the same problem today. Did you find a solution, or did you have to buy a new non-original control.? //Michael
 
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