Used Jump Bafang Hub for Budget Build?

[spaceship]

I received all my parts, laced the wheel, built a battery, and finally have the bike assembled and in testing phase.

One issue I am having is that the speed display isnt working correctly (kt lcd5 display). It just jumps up to 79kmph and stays at that no matter what speed I am going. Could this be a sensor issue in the hub? Or a programming issue on the lcd5?

 

[Chalo]

One issue I am having is that the speed display isnt working correctly (kt lcd5 display). It just jumps up to 79kmph and stays at that no matter what speed I am going. Could this be a sensor issue in the hub? Or a programming issue on the lcd5?

Download the manual for the LCD5, and set the parameters for your motor. 6 speed sensor pulses per rotation, 100 magnet poles per rotation, 26" wheel, etc.

 

[amberwolf]

By jumps to that speed, do you mean that it reads that speed at power on and never varies until it's turned off?

If it was a sensor problem, you'd likely see either no speed signal or just a wrong one by some factor (like if the number of magnets / poles was wrong in the settings).

A setting might be a problem if it has a setting to choose between multiple speed input wires on the controller, and the one chosen happens to be connected incorrectly to a continuous-frequency signal somewhere that happens to work out to the number you see with whatever the number of poles/etc are set to in the speedo settings.

Otherwise it's probably just a miswire, to that kind of signal. Where it might get that kind of signal from, I don't know.

If it is actually hooked up to a speed sensor (either a motor hall or hte built in sensor on these Jump hubs) it should get a signal that varies, even if the actual number was wrong.

 

[spaceship]

If i walk with the bike slowly 2 or 3 kmph it registers 15kmph. So it is picking up a signal from the hub relitive to speed, but it is way out of whack registering way higher than it should.

Looking at the programming manual there is

P1 = motor gear reduction ratio x number of rotor magnet pieces (1-255)

This is set to 87

P2 = wheel speed pulse signal setting (0-6)

This is set to 1

It seems like it must be related to these settings. Does anybody know what these settings should be for this motor?

 

[spaceship]

One issue I am having is that the speed display isnt working correctly (kt lcd5 display). It just jumps up to 79kmph and stays at that no matter what speed I am going. Could this be a sensor issue in the hub? Or a programming issue on the lcd5?

Download the manual for the LCD5, and set the parameters for your motor. 6 speed sensor pulses per rotation, 100 magnet poles per rotation, 26" wheel, etc.

Thanks! I set p1 = 100 and p2 =6 it seems good now, topping out at about 30kmph which seems about right

 

[Chalo]

Download the manual for the LCD5, and set the parameters for your motor. 6 speed sensor pulses per rotation, 100 magnet poles per rotation, 26" wheel, etc.

Thanks! I set p1 = 100 and p2 =6 it seems good now, topping out at about 30kmph which seems about right

Cool. You can check accuracy with a GPS speedometer app on your fone, and fine tune the values if accuracy is important to you.

Uninstall the speedometer app afterwards, because most of them are way too big and probably contain spyware.

 

[wturber]

Download the manual for the LCD5, and set the parameters for your motor. 6 speed sensor pulses per rotation, 100 magnet poles per rotation, 26" wheel, etc.

Thanks! I set p1 = 100 and p2 =6 it seems good now, topping out at about 30kmph which seems about right

Cool. You can check accuracy with a GPS speedometer app on your fone, and fine tune the values if accuracy is important to you.

Uninstall the speedometer app afterwards, because most of them are way too big and probably contain spyware.

Alternatively, reset the LCD odometer and ride some route that you can easily check on Google maps. If the odometer distance is too short, the speed is under-reported. If too long, then over-reported. The odometer should be calculated from the same data as the speedometer. The longer and simpler the route, the better this will work.

You should be able to get pretty accurate results while avoiding comparing your phone and speedo while riding. Also, while GPS speedometers are cool (I use the one in my watch while cycling), they generally have a bit of lag. To do a good speed check comparing GPS to non GPS, it is best to have some extended straight section where you can try to maintain a steady speed.

 

[ynot]

Programmed the jump motor on my bike to 6 speed sensor pulses per rotation, 100 magnet poles per rotation, 26" wheel, and the speedo readout dropped accordingly. Still have not programmed the pair on my freighter trike so it reads 60 to 80 KPH, makes me feel like am Louis Hamilton on an ebike.

 

[docw009]

Torque arm on other side?

 

[calab]

One torque arm is fine for a low powered hub like that Bafang.

Personally, I been rocking one custom made torque arm out of steel and hose clamps.
One torque arm
52v 35a system
I do however feel a slight pull to one side on take off, more so with a heavy weight
Front hub motor
Leaf 1500w
36v 35a controller I use the 52v battery with bms on.

 

[Chalo]

spaceship.jpg

Torque arm on other side?

It's a mistake to use a hub motor with a suspension fork. You may not regret it immediately, but nothing good can come of it.

 

[methods]

I had a front hub detach going 22 or 27mph. It is posted here somewhere. That is when I discovered time is relative.

After that
My rule for front hub on shock is that my torque arm(S) have to do 100% of the job with no axle nuts.

* Braking torque
* Accelerating torque
* Retention

I much prefer rear mounted motors. For me to front mount on skewers... I had the notch out the drops. For ghetto build fine. For best practice, nah.

-methods

 

[Chalo]

Reversing torque such as you describe is what makes your axle nuts unscrew. Good thing a hub with a one-way clutch like the one in the topic title can't do that.

Until there's a better way of anchoring hub motor torque than a flatted axle, I think it's foolish to use a hub motor for braking.

 

[methods]

Fair

 

[LewTwo]

Until there's a better way of anchoring hub motor torque than a flatted axle, I think it's foolish to use a hub motor for braking.

The Grin All Axle Hub Motor
https://ebikes.ca/product-info/grin-products/all-axle-hub-motor.html

 

[Chalo]

Until there's a better way of anchoring hub motor torque than a flatted axle, I think it's foolish to use a hub motor for braking.

The Grin All Axle Hub Motor
https://ebikes.ca/product-info/grin-products/all-axle-hub-motor.html

Yes, there's that, and the GMAC too.