TSDZ2 speed sensing or torque sensing issue?

[jeanl]

Hi guys,
I've had a TSDZ2 (48V) installed on my wife's bike for over 6 months now, and so far I've had mixed results: 1 month after installing it, the torque sensor crapped out, so I had to send the motor back for diagnostic and repair. Took 1 month + but the motor was fixed and we've enjoyed the bike without problem until a couple days ago.
Here's what happened:
My wife was biking with me when she completely lost assist, unless she used the throttle.
I took a look and the display shows a speed of 0 no matter what so I thought, ok, it's just the speed sensor not registering, once I fix that the pedal assist will come back.
I fidgeted with the speed sensor magnet until it would work again (it was the first time I had seen that problem BTW, it had worked without flaw so far). But to my surprise assist didn't come back.
So far, the bike only provides assist when using the throttle. It's as if the torque sensor is not providing any data.
So I have a few questions:
- Have any of you guys run into similar problems?
- It's very suspicious to me that the speed sensor would crap out, and start working again but assist wouldn't come back. Is it possible for the speed sensor to output a non-zero speed, but for the motor control to act as if it was getting a 0 speed signal (e.g., does the speed sensor send more than 1 signal? one's correct but the other isn't?). I would love to test a replacement speed sensor but I don't have one handy of course...

Thanks for any pointer.
I would like to avoid having to send the unit back for service...
Jean
P.S. When it works, the motor is really awesome, it feels very natural and pleasant, I only wish it were more reliable ...

 

[jeanl]

Well, I'm pretty sure it's the torque sensor that got shredded. I was using the bike today (with throttle) and the unit started making a grinding noise, and the pedals completely froze. I'm guessing the torque sensor got shredded inside the motor (I remember seeing that in the super-long thread about the TSDZ2).
Bummer
J.

 

[Drum]

Hi Jeanl,
That's a pain to lose two torque sensors!
There is a way to get into a buried menu on the controller and see what the output of the torque sensor is.
Try this
viewtopic.php?f=28&t=79788&hilit=hidden ... 5#p1405380

Getting the timing right in pressing the buttons to get to the buried menus is tricky, but you get there in the end.

If you see the torque sensor output changing with different force on the pedal, the sensor is probably working, if it doesn't change the sensor is probably shot.
If you look at page 88 of the very long TSDZ2 thread you will find a post I did just after changing a torque sensor. With this and the videos that Jbalat has made about stripping the TSDZ2 motor, (https://www.youtube.com/watch?v=u-SY0rGMEMo) you should be able to change the sensor yourself if you are used to playing with mechanical items and have the tools.

Good luck,
Dave

 

[jeanl]

Thanks Dave,
I'll take a look!
I definitely would prefer changing it myself rather than having to send the unit for repair...
Jean

 

[jeanl]

Well it was definitely the torque sensor.
I took the motor apart, here are the pictures of what I found:





The wiring in the torque sensor (I didn't realize there was any wiring in there) apparently came undone and got shredded. There is also a piece of plastic visible on the top pic to the left of the sensor plate, which probably came from the underside of the sensor, which I still have to pull out.

I do remember another case of a torque sensor disintegrating on the super long thread (https://endless-sphere.com/forums/viewtopic.php?f=28&t=79788) but I have to find the exact page.

As I said this is the second torque sensor that fails on us.
There's no doubt that if I had imagine that all this was going to happen I would have bought another motor (or none at all given that there aren't many with torque sensing, which I really wanted). I paid $400 for the unit, and I've had it 8 months...
It's mounted on a townie! Not a mountain bike or anything, the least sporty city bike you can imagine!
Not very happy here.
Jean

 

[jeanl]

Here's the post from the user who had the same issue: (Jan 16, 2018 10:06 am)

https://endless-sphere.com/forums/v...351451&hilit=destroyed+torque+sensor#p1351451

Definitely a design flaw here.
Jeanl

 

[Drum]

Hi Jean,
The torque sensor I replaced was broken in a different way: there was a crack in the tube that carries the pedal torque from the pedal spindle to the main drive gear.
I guess there are a lot of these motors in service, but the number of failures we hear about is a bit of a worry.. They are obviously not quite as reliable as you would hope.
Dave

 

[Waynemarlow]

I guess there are a lot of these motors in service, but the number of failures we hear about is a bit of a worry.. They are obviously not quite as reliable as you would hope.
Dave

Mmmm very subjective, take the Bafang series, some millions have been produced, we talked about how un-reliable they were with the Mosfet problems that probably 10 people on the thread had reported, tiny tiny percentage of the total.

Before we get into the reliability issue then perhaps it maybe an idea if any one knew the numbers already produced, remember a 0.1% failure rate in most consumer products would be probably OK, that's 1 in 1000 engines which I would wager we are probably in that zone .

 

[jeanl]

I guess there are a lot of these motors in service, but the number of failures we hear about is a bit of a worry.. They are obviously not quite as reliable as you would hope.
Dave

Mmmm very subjective, take the Bafang series, some millions have been produced, we talked about how un-reliable they were with the Mosfet problems that probably 10 people on the thread had reported, tiny tiny percentage of the total.

Before we get into the reliability issue then perhaps it maybe an idea if any one knew the numbers already produced, remember a 0.1% failure rate in most consumer products would be probably OK, that's 1 in 1000 engines which I would wager we are probably in that zone .

Well, that was also my take on it, when I bought the motor: hoping I wouldn't be part of the unlucky ones... But I didn't have that luck. The fact that two torque sensors can fail in less than 8 months on a bike that is not being used hard at all (city use, Townie city bike, definitely no mountain biking!) is more than worrisome. Maybe something's wrong with the rest of the motor that causes this failure, it's very hard to tell...
But I agree with you: when you go on forums, you don't hear from people who have no problems with the units, you hear from the people who do, so that's hugely biased!

 

[jeanl]

Here are more pics of the completely dismantled torque sensor: