New "Lingbei MM28.250 torque sensor mid drive"

[Drum]

Hi F2,
Thanks for the information on this motor. It looks as though it is promising if we can connect to it and alter the operating parameters.
I e-mailed Lingbei directly saying I thought that their motor looked promising, but that (based on your report) it probably wouldn't suit people riding technical terrain on mountain bikes, and asking if programming cables and programs were available to download so technically competent customers could tune the controller to suit their preferences.
Here's their reply:

"Thank you for your recognition and valuable suggestion on our motor. We will improve our shortages as soon as possible.

It is ok to provide the programming cable per customers request and upload the programs on our webite in the future for DIY consumers selection. But we can't provide the programming cables to every consumers to avoid the potential defectives caused by reprogramming the motor again and again, please kindly understand. We prefer to let the distributors or store sellers to program the motor for consumers.

Hope we can cooperate in the near future."

Looks promising. It may be that the programming in your motor was chosen by Okfeet rather than Lingbei, and that Okfeet and other retailers could offer the motor in different "versions" for end users that didn't want to get involved in reprogramming after purchase.

Now I see from your latest post that you already have a programming cable on the way. I await further reports once you get your cable!

 

[fantasy2]

The programming cable I ordered is for directly programming the STM32 opening the possibility to write open source firmware.

Thanks for sharing this info! I wonder if it would be as simple as with Bafang programming. In that case you don't have to open the motor(this is by the way relatively hard to do as they sealed it completely to prevent moisture coming in).

Pictures!

 

[anttipaa]

I would like to buy this kit because I like its shape more than tsdz2 and blue gear seems to be more durable. But I have to wait and see is there a way to custom program it. Right now TSDZ2 seems to be programmed better and there is custom software from casainho. I hope someone is able to do same software for this motor too! Then I will change TSDZ2 to this.

 

[AWD]

Stock chainline doesn't look too bad. How many teeth and what BCD is the stock ring? Looks like there is potential to run a smaller than 42t ring which would also play into setting the torque levels.

Just curious though how the drive side seated against the bb shell with the chamfer?

 

[fantasy2]

I would like to buy this kit because I like its shape more than tsdz2 and blue gear seems to be more durable. But I have to wait and see is there a way to custom program it. Right now TSDZ2 seems to be programmed better and there is custom software from casainho. I hope someone is able to do same software for this motor too! Then I will change TSDZ2 to this.

So we learned that the manufacturer has a cable and software to modify their existing software.
I'm waiting for another programming cable to build my own software like the TSDZ2. I want some more functionality that's not available and like to tweak torque/cadence ratio differently.

Stock chainline doesn't look too bad. How many teeth and what BCD is the stock ring? Looks like there is potential to run a smaller than 42t ring which would also play into setting the torque levels.

Just curious though how the drive side seated against the bb shell with the chamfer?

It's pretty good at my bike actually. The 42t ring is exactly in the middle of my cassette. I was expecting much worse. I'll measure the BCD when I get back to my bike again. I'm sure you can run smaller rings, plenty of room.

I'm not experiencing any problems with to those teeth at the drive side. The bb shell of my bike has a small chamfer and it bites in it. I have removed the motor several times without problems and I don't see any damage to the thread(only some bite marks on the shell's chamfer).

Some pictures of my bike:

 

[maitilupas]

mooi ah tas!,

its good to find more people doing themselves with touring bikes, i did a rear hub with a Gazelle Kathmandu , i would also lke to jump working into adding this mid drive, very curious about it

 

[fantasy2]

Haha, yeah, waiting for some decent bike bags.

Touring bikes are awesome for commuting. I do 15km one way and it's just faster and more comfortable than a city bike.

 

[Bigwheel]

Looks good Fantasy2. The bolt pattern suggests that the existing Bafang style aftermarket offset rings would work if there is the need to bring the chainline in.

 

[fantasy2]

Looks good Fantasy2. The bolt pattern suggests that the existing Bafang style aftermarket offset rings would work if there is the need to bring the chainline in.

The BCD is 76mm. Think this is pretty standard?

I need to correct some information based on today's findings:
- There are three hall sensors inside. The motor does not run without them(and so it is not sensorless, allowing for higher torque and smoother driving). They are latching type H4601. This is the 5 wire connector.
http://www.haierxikj.com/en/UploadFile/Photo/2016-4/2016041810390984128.pdf

- There is 4 wires for another sensor. I have seen bafang having 4 wires for the PAS sensor but the supplier claims it is PAS+torque so I wonder how this is connected? VCC, GND, Signal PAS(hall?) + signal torque? Strange.. The supplier is trying to send me a manual to disassemble the shaft so I can take a look.

- The microcontroller is the STM32F031C6T6. 32-kByte, 48MHz. Was hard to read on initial picture, now I got better light

 

[fantasy2]

So the error 24 I had in the display turns out to be a defective hall sensor. One of them was not responding causing the motor to make vibrations on high cadence speed. I sent a video to the supplier and they will send me a replacement on Monday. Very happy.

I explained them that the current torque and PAS balance is not optimal for every type of bike. They understand and are now going to discuss this with the factory and try to get a programming cable and software from them so I can tweak the motor for different bikes.

My next step is to map all the wires to the microcontroller so we can start on writing new software.

I you're about to decide which motor to buy, I can definitely recommend this one. Lot's of good things to come in the future 8) .

 

[notger]

I you're about to decide which motor to buy, I can definitely recommend this one. Lot's of good things to come in the future 8) .

Hmm, to be honest it really dounds interesting.
Im still sceptic how the torque sensor would actually work with 4 pins, either it does not use direction detection, or is "torque simulation".

So im still curious about further experiences, also about power limits watt-wise, and sure,...whooow open source controller programming

 

[fantasy2]

I you're about to decide which motor to buy, I can definitely recommend this one. Lot's of good things to come in the future 8) .

Hmm, to be honest it really dounds interesting.
Im still sceptic how the torque sensor would actually work with 4 pins, either it does not use direction detection, or is "torque simulation".

So im still curious about further experiences, also about power limits watt-wise, and sure,...whooow open source controller programming

Yeah, I'm still sceptic too. However, they confirmed multiple times that it really has a separate torque sensor and the company sells torque and cadence sensors as a package without motor as well.

If it's torque simulation then I'm very disappointed.

It's probably wired similar to this one:
https://opensourceebikefirmware.bitbucket.io/development/Torque_sensors--BMSBattery_torque_sensor.html
https://bmsbattery.com/ebike-kit/689-b-b-torque-sensor-system-ebike-kit.html

Forwards movement is a 0-5volt pulse, reverse is 5volt continuous high.

When I have time i'll power those wires, just to see what my oscilloscope shows.


I'm stress testing this thing pretty heavily now, I maybe should add a datalogger for real power consumed(The display shows 16amp of current drawn which would mean about 800Watt) but it's really strong. In most heavy gear which is 42t front and 12t back, the throttle just pulls the bike quickly to speed. It's not good for the chain and gears so I don't do it often. When driving purely on the throttle, the bike quickly goes 40km/hr, which is a software speed limit.

 

[Drum]

The Tongsheng motor definitely has a full 2-sided torque sensor, and there are only two wires connecting it to the controller. These wires are connected to a stationary coil in a plane perpendicular to the pedal shaft.

There is a matched roatating coil on the torque sensor, and the two coils are gently forced against each other by 3 light springs behind the stationary coil. The rubbing faces of the coils are coated with what looks like fibreglass / teflon tape.

So if Tongsheng can supply power to, and receive signal from, the torque sensor through only two wires and induction between two coils, the thought of 4 wires doesn't seem too much of a problem !

 

[notger]

(The display shows 16amp of current drawn which would mean about 800Watt) but it's really strong.

Ok, shit, I'm getting really interested now.
It would mean, the Controller does not controll Wattage, rather than top speed nd probably max battery Amps.

So if the will be a customization software to get more torquy controll, i will probably also order one.

Where did you get yours ferom ?

 

[fantasy2]

(The display shows 16amp of current drawn which would mean about 800Watt) but it's really strong.

It would mean, the Controller does not controll Wattage, rather than top speed nd probably max battery Amps.

Exactly.

So if the will be a customization software to get more torquy controll, i will probably also order one.

Where did you get yours ferom ?

I got mine from aliexpress OKFeet. They don't have them always on stock as they sell out quickly at the moment. Just send them a message and they will respond back quickly. They have a tax free route as well. 8)

 

[eyebyesickle]

Nice...

I'm trying some different displays, and HEX/programming files to see what we can tweak with these! I'm excited about these!

So far, the manufacturer doesn't want the power going over 17A (similar to Tongsheng recommendations) but I have a feeling this motor can handle a little more.

Can't wait to see what we can do with programming to tweak/smooth out the torque sensing / pas ratio etc...

 

[fantasy2]

Nice...

I'm trying some different displays, and HEX/programming files to see what we can tweak with these! I'm excited about these!

So far, the manufacturer doesn't want the power going over 17A (similar to Tongsheng recommendations) but I have a feeling this motor can handle a little more.

You got a motor as well for testing? Nice! How does yours run in your experience compared to the TongSheng?
The voltage rating of the internal caps is 63Volt. So it should be able to run on 52Volt packs. However, this is not officially supported in the C600 display.

The motor seems in many ways similar to the BBS02 which (i think) is limited to 25A?

Can't wait to see what we can do with programming to tweak/smooth out the torque sensing / pas ratio etc...

Yep, can't wait!

Those displays look nice, are they from lingbei as well? The display in the middle has exactly the same buttons and display except that the display is rotated 90deg. I know they have C600 per default and C300 as option as well(small display)

 

[fechter]

Inside the motor looks almost exactly like a Bafang. The controller looks very similar too. I wouldn't be too surprised if the Bafang software worked with it.

 

[fantasy2]

The motor is made by ex-engineers from bafang. They probably took the design with them when they left the company. Wouldn't be the first time. :lol:

The controller is not the same(they added torque control) and there are some dimensional differences. But yeah, it looks pretty similar!

 

[eyebyesickle]

The BBS software doesnt seem to work with it, there are alot of differences... of course someone more savvy may be able to make it work, but I think a complete re-work of software would be in order, considering the torque sensing differences etc...

As for the displays, yes, from LingBei directly, I have been negotiating with them over the last few weeks, the displays I showed pics of kind of compete with the dpc14, and dpc18, the horizontal and vertical color displays BBS uses....

 

[Uturn]

are you happy with the motor's characteristics?
> standard cadence is high enough, or a bit low as the TDSZ2's?
> chainring with standard BDC dimensions will fit?
> possible to mount two chainrings?
> torque sensing can be adjusted for natural response?
> weight of 3.6kg is correct, or is it heavier?

 

[anttipaa]

Eyebyesickle are you going to start selling these kits? Can you ask them to program it better from factory? Same way as TSDZ2 is programmed? And with throttle/light cables etc. I like that smallest display! Im not ordering tsdz2 because I have to wait and see how this kit performs. 25a would be nice!

 

[fantasy2]

Got the hex dump of the microcontroller attached for anyone feeling like disassembling it and taking a look

 

[eyebyesickle]

Got the hex dump of the microcontroller attached for anyone feeling like disassembling it and taking a look

What version/power level is yours?

I'll have all the factory hex files soon, to compare with each other and find power level differences etc... so I can do more than just switch motor profiles (basically looking to do the same thing I do with the TSDZ2 which is adjust voltage and current as needed, but I also need to mod the torque sensing if I can)



antipaa,

Yes I will be offering them, pending them passing the 'TEST'. It would be nice to have them properly factory programmed, because unlike the BBS or TSDZ2 series, these need to be opened to program... Although I am going to see if i can make a separate programming cord, to connect to the display etc, I need to do a pinout map for these to see if that is possible...

So far, these seem very promising... and the new displays are very nice quality, and a bit cheaper than the BBS equivalent models...

within 2 weeks I'll have a proper review, workup, whatever info is to be had...

 

[fantasy2]

Got the hex dump of the microcontroller attached for anyone feeling like disassembling it and taking a look

What version/power level is yours?

I'll have all the factory hex files soon, to compare with each other and find power level differences etc... so I can do more than just switch motor profiles (basically looking to do the same thing I do with the TSDZ2 which is adjust voltage and current as needed, but I also need to mod the torque sensing if I can)

This is the 48Volt, 500Watt version with 5 PAS levels. Supplier told me they did not change any settings from factory default.

It would be nice to have them properly factory programmed, because unlike the BBS or TSDZ2 series, these need to be opened to program... Although I am going to see if i can make a separate programming cord, to connect to the display etc, I need to do a pinout map for these to see if that is possible...

Good luck. I've opened and closed mine about 4 times now and the wires have no space at all. Really tight in there. After you unscrew the three screws at both sides(they are torx with a pin!) for the first time, you need to get a sharp knife to break the silicon seal. Somewhat difficult but as soon as it goes it gets easier.

I was thinking about routing a separate wire through the plastic where the other cables enter and exit. You need a 4 pin cable(VCC, GND, RESET, SWIM). If I remember correctly, all 8 pins in the 1to4 cable are occupied.

Some speed info:
PAS lvl 1 feels most like torque only. Not strong, more like compensating the extra motor and battery weight.
PAS lvl 2 brings me to 31km/hr
PAS lvl 3 to 34km/hr
PAS lvl 4 to 40km/hr
PAS lvl 5 to 40+

The display still uses UART so I guessed that they would send me a cable so I could program all the settings over UART.. If that's not the case and I really need to reflash everytime, then that's stupid. Why didn't they implement this?! This is how bafang does it.