New Generations of BB Torque Sensors (Bafang and Sempu)

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notger   100 W

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New Generations of BB Torque Sensors (Bafang and Sempu)

Post by notger » Jun 03 2018 10:45am

Hi,

I'd like to make people aware of two new BB - torque Senors witch look really interesting.

One is the "New Generation Sempu T4" measuring torque on both sides cause measuring the chainring-force.
Image
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https://www.ebikes.ca/documents/Sempu_S ... l_2018.pdf
https://de.aliexpress.com/item/dual-sid ... 0.0.NQeeH7

with following specs:
sempu.JPG
sempu.JPG (122.75 KiB) Viewed 9759 times
the other one the Bafang SR PA31.32.ST and other Versions of it.
Using the same mesuring method, but with different specs.
Image
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http://www.bafang-e.com/en/components/c ... 0112s.html
https://de.aliexpress.com/item/Hot-sale ... 39.90158.0
-----------
Specs.:
bafngt.JPG
bafngt.JPG (46.23 KiB) Viewed 9759 times
the interesting thing on Bafang is the the
Input Voltage(DCV) 4.2 - 5
Output Voltage(DCV) 0.74 - 3.2
cause that ??could allow to use the Bafabg without potential Pre-Controller like CA in any throttle-input.
But it could also be that it is specially produced for bafang controllers and would make strange behaviour acting as throttle.


So my main Motivtion for this thread is, instead of buying and testing both by my own, and mayb finign out that one of them is trash, i ask you for potential experiences with those Sensors ???

greets
Notger

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notger   100 W

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by notger » Jun 03 2018 10:57am

And now, ontop of that, another Motivation would be to create a custom mi-drive-freewheel-bb-torque-sensor for my several mid-drive options with freewheels.

This could look like this.:
Image

adding a.:
Image

to this Spot (lets call it chainring-spider-mount).:
Image

any ideas on that ??

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by tangentdave » Jun 03 2018 12:35pm

I'd make an adapter with BSA threads, the adapter would attach to the torque sensing BB using the splined/bolted interface. All the hardware for flanged freewheels could then be re-used. Chainline may be skewed outboard but a custom offset spider is easy.

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notger   100 W

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by notger » Jun 03 2018 1:05pm

tangentdave wrote:
Jun 03 2018 12:35pm
I'd make an adapter with BSA threads, the adapter would attach to the torque sensing BB using the splined/bolted interface. All the hardware for flanged freewheels could then be re-used. Chainline may be skewed outboard but a custom offset spider is easy.

-dave
exactly my idea, just not sure, if the 1,37" / 35,8mm thread would fit on the......
Image

and another Problem could be that the Sqare tapered crank would not, or very tightly fit on the crank ??
Many coulds,....Probably goot to test it.

What do you think about the Bfang ? or any experiences ?

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by notger » Jun 03 2018 1:24pm

Does anyone know this multi-tooth standard that Bafang is using on its chainring-spiders ? (if it is any standard)

Image

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by tangentdave » Jun 03 2018 2:31pm

I bet the 1.37"x24 threads are the same diameter as the 5 bolt pattern, so the FW would have to stick out over the spindle and impede on the crank. Would need some minimum spindle stickout to give the FW room.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by Drum » Jun 03 2018 3:32pm

Lingbei, a manufacturer, is also listing a torque and speed sensing bottom bracket on their website: http://lingbeimotor.com/a/products/p1/7.html

Little information, and I don't see any output flange so I assume it is only single sided. Also it is only square taper, so I wouldn't personally be interested in fitting one to a mountainbike, but I thought I would add the information to this thread in case it is useful to someone.

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 03 2018 5:14pm

That Bafang BB crank looks really promising with those input/output voltages. Since I have a Phaserunner that has programmable throttle levels I think I’m going to pick that up for my bike.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by notger » Jun 05 2018 2:57am

zro-1 wrote:
Jun 03 2018 5:14pm
That Bafang BB crank looks really promising with those input/output voltages. Since I have a Phaserunner that has programmable throttle levels I think I’m going to pick that up for my bike.
It does, but not sure if its supported by the CA as pre-controller ?
Probably it has its own "intelligence" inside ?

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 05 2018 5:38pm

notger wrote:
Jun 05 2018 2:57am
It does, but not sure if its supported by the CA as pre-controller ?
Probably it has its own "intelligence" inside ?
I don’t use a CycleAnalyst, just the Phaserunner by itself
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 05 2018 6:10pm

I just ordered the Bafang BB it was $149 USD from the US/EN site. I’ll need to get a chainring and pedal arms now too...

EDIT: The model the EURONAU is selling uses the square-taper shaft, not the splined shaft as linked to above in the original post - just FYI.

EDIT 2: I figured I should add the specs for the square-taper version here as they are slightly different from the version linked above.

Specifications:
Type Torque Sensor. Speed Sensor
Signals (Pulses/Cycle) 32
Input Voltage(DCV) 4.5 -5.5 (slightly wider range than the other model)
Output Voltage(DCV) 0.74 -3.2
Resolution (mv/N.m) 35
Operation Temperature -25 - 45 ℃
Shaft Standard JIS
Weight (g) 650-780

Mounting Parameters:
BB Width(mm) 68, 100, 73, 84, 110, 120 (it look like Bafang makes this in different BB widths, though the one on AliExpress is only 68mm)
Mounting Position Bottom Bracket
Cable Length(mm), Connector Type 150 G6.4 / 950 G6.4

Tests & Certifications:
IP IP 65
Certifications EN 15194 / EN 14764 / ROHS
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by aCeMadMod » Jun 05 2018 7:53pm

hi hopeful they make it in isis. bb

I hate spare bb



or are Dave going to mod some ? :?:


if so how much are they


all keep modding

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 05 2018 8:55pm

I really wish it was possible to buy direct from Bafang. They have 4 items on their site that I would buy today if they had direct sales. I haven't found the Bafang BB with ISIS shaft standard on AliExpress. The EURONAU BB is listed 3 times, but it's the same square-taper JIS BB. I personally think JIS is fine for hub-drive bikes. I could see the benefits of an ISIS BB in the case of a mid drive that is powering through the shared chainring.

I really like that these new BB's all use a torque sensor that reads torque from the chainring spider instead of through bending of the shaft. And the integrated PAS sensor is just an added benefit. I am really pumped to see how this works with the torque throttle of the Phaserunner.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 05 2018 9:00pm

I grabbed a dimensional diagram of the Bafang BB
Screen Shot 2018-06-05 at 7.22.14 PM.png
Screen Shot 2018-06-05 at 7.22.14 PM.png (174.13 KiB) Viewed 9563 times
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 10 2018 3:13pm

The Bafang BB I ordered has shipped. As soon as I get it I'll post pics here. I'll probably end up documenting the instal and testing in my build thread, but I'll be sure to link that here for easier reference.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by AF7JA » Jun 11 2018 8:19am

I am looking at this wondering if it would be compatible with the GNG. Any thoughts?
I would rather avoid a throttle if at all possible.


Thinking about it, I am more interested in the Luna/Cyclone 3000W unit; however, I expect that when it comes time to order I will return to the BBS02, like I had before.
Last edited by AF7JA on Jun 11 2018 7:05pm, edited 1 time in total.

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by PaulD » Jun 11 2018 3:34pm

Just got a Sempu T4. Although it looks like it has external bearings on the non-drive side , it doesn't (the drive side has an external bearing to make room for the sensor bit), which is ok, and it will allow us to machine some of the material away to make room for mid-drive motor mounting plates, and possibly a freewheel. The spider mount is too large to adapt to freewheel threads easily. So, I will probably be looking into modifying a freewheel to fit. It seems to work as advertised on the bench. I'll try to get it into a bike today.
Sempu T4.png
Sempu T4.png (428.25 KiB) Viewed 9368 times

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 16 2018 2:44pm

I got the Bafang/EURONAU bottom bracket today. I'm not sure I'm going to be able to make it work with the Phaserunner on the throttle connection. While the input and output voltages are correct to use as a throttle, this bottom bracket has 6 wires in the cable rather than just 3 as you'd find in a throttle.

Here's pics:
bb-1.jpg
Bottom bracket with bearing cups removed
bb-1.jpg (177.25 KiB) Viewed 9267 times
bb-2.jpg
Bottom bracket with bearing cups installed
bb-2.jpg (165.84 KiB) Viewed 9267 times
bb-3.jpg
wires coming from bottom bracket
bb-3.jpg (95.91 KiB) Viewed 9267 times
I have a feeling this BB was designed to only work with specific controllers and isn't a universal component.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by Drum » Jun 16 2018 8:55pm

Probably 3 of the wires are for the torque signal (input +, common -, and analogue torque signal out), and the others are for the cadence signal.
Did the supplier not send you a connection diagram? If not, that's pretty slack! Contact them and ask for one.

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by zro-1 » Jun 17 2018 12:10pm

Drum wrote:
Jun 16 2018 8:55pm
Probably 3 of the wires are for the torque signal (input +, common -, and analogue torque signal out), and the others are for the cadence signal.
Did the supplier not send you a connection diagram? If not, that's pretty slack! Contact them and ask for one.
That's my suspicion as well regarding the wiring. I should have known that it would have the additional wires, but I was hoping it was something totally new since the input/output voltages matched a throttle.

No, the supplier didn't even include a packing slip. It was literally just the BB parts in a plastic bag that was put in a padded envelope. I've reached out to them and they said they'll provide a wiring diagram for me. We'll see...

EDIT: Update: they wrote back and said they couldn't get a wiring diagram. Totally useless reseller. I gave them a poor rating.
Last edited by zro-1 on Jun 23 2018 11:44am, edited 1 time in total.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by PaulD » Jun 21 2018 4:45pm

Really happy with the response and feel of the Sempu T4. So much better than the left-leg only Thun sensors with lower pole count. The main issue is the lack of freewheel which results in an occasional tug on the pedals with the inertia of the motor and gears slowing down. Also, it's nice to be able to back pedal without dragging the motor around.
SempuT4 installed.png
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by -dg » Jun 22 2018 9:55pm

There seems to be a lot of info on this https://www.aliexpress.com/item/dual-si ... 84280.html page, but there is a bit of confusion about the exact power supply voltage and the role of the green vs yellow wires. If you have a meter with a needle or a scope it should be easy to work out.
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by stancecoke » Jul 04 2018 4:47pm

zro-1 wrote:
Jun 16 2018 2:44pm
I got the Bafang/EURONAU bottom bracket today.
There are some new pictures of the Bafang sensor at the german pedelecforum. The sensor is used in some Kalkhoff and Raleigh ebikes obviously. The brand of the motor system is called "Groove go" by Derby-Cycle.
But the pinout of the six wires is still not known... :(

regards
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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by atarijedi » Jul 05 2018 4:07pm

Anyone know where to get the Sempu T4 model in different BB widths? From their website, they offer a version with for 100mm BB, so it will fit on fat bike frames with a 100mm BB. But I can't seem to find it anywhere.

http://www.sempu.net/newsshow.php?id=1

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Re: New Generations of BB Torque Sensors (Bafang and Sempu)

Post by PaulD » Jul 07 2018 5:12pm

atarijedi wrote:
Jul 05 2018 4:07pm
Anyone know where to get the Sempu T4 model in different BB widths?
I got one on Alibaba: https://czkuake.en.alibaba.com/
Interestingly, the housing is partially 3D printed. Sempu must not be making very many 100mm units.

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