Bosch Perfomance Line Throttle Mod

[Gazoo]

Hey,

I got my hands on "broken" Bosch Performance Line motor for cheap. The issue with it seemed to be the electronics - error 500 and 531.
I've been searching for one like that for quite some time because I had a plan - I wanted the Bosch motor equipped with throttle.

Before I start describing the process let me explain my choice. I already have Kona Stinky converted to an ebike, with 2600W hub motor that I converted myself, I love it, but it having no gearing makes steep climbs tough, so i thought about making another bike using central mounted motor. The Bafangs BBS seem to me a bit delicate, it decreases clearence and it's not cheap compared to hubs, and still I'm not convinced to mid drives - this project is for me to verify which is better for me (the Bafang Ultra however seems a great option if only it was cheaper).
Bosch on the other hand seems sturdy, compact and hides neatly between the cranks - thats what I like about it. What I don't like is that there is no easy way to DIY them. Expensive batteries with little capacity, CAN communication, no throttle.
That is when i got an idea of replacing every electronic part of that system with something more friendly - chinese KT controller and a custom battery, this would give me mechanically great engine with easy to use and modify electronics.
Still, you need to remember that this project is done on a cheap, there might be some better systems for this application, but i really wanted to go this way, to test myself and possibilities of this motor.

So i got this engine for cheap - scrap value almost. I disassembled it, removing the controller and one other PCB which to seemed to be the hall sensor (correct me if I'm wrong).

After disassembly my first obstacle seemed to be the lack of hall sensor in the motor itself (just three phase wires coming out of it), but it didn't stop me. I bought SS41 halls which I knew worked well with chinese controllers and placed them in the motor assembly:

Also in the picture you can see the 125deg.C termal protection that i glued with heat transfering glue.
Halls are placed 120 degrees apart form each other as the rotor has 14 poles (calculations based on this guide - http://mitrocketscience.blogspot.com/2011/08/hall-effect-sensor-placement-for.html?m=1).

To complete the package i bought the Hailong battery case and the KT controller that hides in the rail of the battery (https://www.aliexpress.com/item/KT-sine-wave-controller-36V-48V-250W-350W-Hailong-controller-small-Hailong-battery-case-controller-36V/32967236787.html?spm=a2g0s.9042311.0.0.69054c4dxKxkHe)
Battery is 36V 10S5P.

Afted few hiccups with connections whole thing started spinning:

https://www.youtube.com/watch?v=6SQxieZBEJA&frags=pl%2Cwn
https://www.youtube.com/watch?v=GIU7ixnXBFw&frags=pl%2Cwn

The issue i have right now is that with heavy acceleration the power cuts out - when sitting on a bike on heavy gear, giving it full throttle fast it jumps and cuts out immediately. I understand that it might have no power to move on heavy gear, but my other motor buzzes steadily trying to spin, and this configuration just cuts it out. It's not the battery cut out (I have the leds between the battery and the controller and these don't turn off). When adding throttle gently it moves, and drives like it should, only when giving it too much it just cuts out. Any ideas what's the problem?
I tested the hall sensors and they seem to be ok:

https://www.youtube.com/watch?v=Hkpx-kURi14&frags=pl%2Cwn
https://www.youtube.com/watch?v=v9rCFiRwzco&frags=pl%2Cwn

Thanks for your help in advance and I will keep you updated on the progress of the project.

 

[Richo27]

Very interested in what you are doing here. I have a Bosch performance line CX powered bike. As you said its a neat mid drive motor, in its stock form it puts out a decent amount of torque, but I would like a throttle as well and the option to run custom battery packs.

 

[Gazoo]

It seems like all the Bosch motors can be modified, it just takes some work and voila - very happy with this setup so far.

 

[uolihp]

Hello Gazoo, I find your idea really great ! I am very interested in your work,
I would like to do something similar and if you have time to answer me I would have some questions for you.
- Do I understand that the hall sensors are glued? With what glue?
- How to find the exact position on the stator?
- I would like to install a programmable controller, if possible in Open Source, what are the parameters to know for the controller?
Thank you, if you have time to answer me ,
cordially,
Philippe

 

[leffex]

Good work Gazoo!

You're kind of the first (at least) that I know of who have managed to do this!

Awesome!

I did use another controller on a bafang but it feelt jerky and I put down that project. One thought I had when I read about your story was that if you change highest voltage that the throttle is able to put out. Will this fix your problem or is the problem more of a physical nature like a clutch in the motor.

 

[leffex]

Nastrovia!

https://endless-sphere.com/forums/viewtopic.php?t=96492
Are all the hall sensors 120* apart? Above thread is hall sensor layout on a bafang. Shouldn't they be in like a group?

 

[andrea_104kg]

why you don't use a sensorless controller?

 

[uolihp]

Yes Andrea, why not ? maybe a good idea?
I am not well informed, can we really use a controller without sensor, what are the disadvantages compared to a controller with sensor?
Do you know a good programmable controller without sensor? A link ?
Thank you very much and cordially :wink:

 

[larsb]

@gazoo:Based on the pics your hall sensors are placed too deep? It just might me the pics but:

They should be on the surface of the stator laminations towards the magnets. Or facing the ends of the magnets

Revolt motors place the halls deep and the effect is that as soon as the current is increased the coil fields switch the hall sensor in the wrong time instead of the magnets switching the halls - you get a cutout due to hall error.

@andrea104kg: Sensored controllers are mostly useless for startup with load - not recommended. the halls should be fixed instead!

@leffex: Hall placement can either be 120 degrees mechanical apart or 120 degrees electrical apart. It does the same job. Electric degrees=(mech degrees)*(pole pairs no)

That this works is because it should be 120 degrees electrical between the sensors for almost all controllers, 120 mechanical is always same as 120 degrees electrical no matter how many magnet poles there are but the opposite is not true. There’s plenty of data here on ES or google it.

 

[electric_nz]

Great idea. I’m guessing the nylon gear and heat generation would limit the power you could pump through it, but it certainly looks way overbuilt for 250W!

 

[andrea_104kg]

this is a tsdz2 motor whith a sensorles controller (from pswpower) , its not very differnt from bosch.
https://www.youtube.com/watch?v=OvpPC61ZaM0
https://www.youtube.com/watch?v=InSiMgWegt4
the problem under load are tipical of hub motor, it may happen that the controller does not understand the direction of rotation of the motor and there is a jerk starting effect. But a pedal stroke is enough to start the engine.
The central engines are much more multiplied than the hubs, and the minimum weight of the foot on the pedal is sufficient to start the engine

 

[Manoch]

Hello. I made the same transformation, without hall sensors, and have the same reaction when I accelerate hard. a crashing noise. I think it's the structure of the engine, I take it as a security. afterwards, it works very well and I have a lot of fun!

 

[Gazoo]

UPDATE:
Still doing this sh*t, Andre.
Previous build went through testing very well, even though the issue with controller cutting off stayed unresolved, I got used to it and see it as more of a feature, protecting the drivetrain.

I decided to build another bike from ground up (the old one goes to my gf).
Frame was the hardest to obtain (full suspension with bosch mount), but one finally popped up:

Did the usuall, just routing the cables in a bit different way:

Mounting the battery - same battery as before lets me swap with my gf, or take two on longer trips:

Finished bike:

This thing rips on jumps, torque on uphills is sick (11-40 9 speed cassete does the job), and it cost the fraction of new stock ebike (plus it has throttle, and about 600W).

Next thing on my list is trying to adapt the stock torque meter inside the engine to use with this thing: https://ebikecomputer.com/
Stay tuned for another updates!

 

[flangefrog]

Why did you dispose of the existing hall sensor board instead of using it?

 

[Vbruun]

The existing board is a sine/cosine encoder.

 

[flangefrog]

Oh right. Maybe it would work with a VESC? I was given a Performance CX motor myself. Haven't looked too closely at it yet (I did open it up) but everything seems fine.

 

[Gazoo]

Oh right. Maybe it would work with a VESC? I was given a Performance CX motor myself. Haven't looked too closely at it yet (I did open it up) but everything seems fine.

Yes it would - that's exactly what I did next.
I have been testing the VESC on my desk few years back and had a set of controller and motor laying around since.
Recently I managed to burn the KT controller I had and decided to test the VESC on this bike. Now it has torque sensor connected as throttle and it all works fine:



It all fits in the original spot of the KT controller with added bonus of being with contact with the frame to act as heatsink