Bafang motor hub and KT sine wave controller without harmony !!

ilexk

Finding my (electric) wheels
Jul 26, 2021
6
0
I am having problems with my new kit, it is a Bafang hub motor 36v 250w CST with all the components from the same brand.
15 A controller and the Display Dz40 Mini.

I don't like how it works.
Nothing like this has ever happened to me before with my previous ebikes (BPM 500w, MXUS and Cute Q100 CST).

Let me explain, if I pedal at maximum power with any of the small sprockets, after a descent when starting a slope the motor does not wake up, not even with the throttle, I first need to go down several gears so that the motor can provide assistance when applying the throttle.

To avoid this anomaly, I have an alternative installation, I only use the Bafang motor with the 15A KT controller and the KT-LCD03 Display and without throttle, this way the behavior is correct, except that the motor does not deliver the same torque as with the original controller and display.
I don't understand the reason for this, since both controllers have 15 amps.
Could it be because the KT is a sine wave controller type?

The ideal would be to be able to use the KT Dispaly with the Bafang controller, but this is not possible since they are not compatible.

Any ideas to get the best performance from this Bafang motor with 45N.m of torque?

Looking forward to hearing your opinions!!

Thank you
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
3,540
1,763
Telford
If both controllers are 15A, they should give the same power and torque. Obviously, for the KT, you need to be on level 5 to get max power any other level will reduce power (assuming you have p3=1)

There are some settings that can effect the power for the KT controller. C5=0 allows maximum current. Any other value of C5 would not be 15A. Different versions can have different software, so it's not possible to give exact guidance.

C14 affects the pedal assist. C14=4 should give the highest selectable value, but I'm not sure whether C14=0 by default gives the max. Try both.

If neither of those solves the problem, you need to fix a wattmeter between the batter and controller to see what's going on, then solder the shunt to get what you need.

One more thing: You should have P3=1 for current control. P3=0 is speed control and has a different max speed for each of the 5 levels.
 
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Sturmey

Esteemed Pedelecer
Jan 26, 2018
525
298
67
Ireland
....Let me explain, if I pedal at maximum power with any of the small sprockets, after a descent when starting a slope the motor does not wake up, not even with the throttle, I first need to go down several gears so that the motor can provide assistance when applying the throttle......
The above appears similar to the reported problem with the earlier Pendleton Somerby bikes and some other kits. You could check your PAS magnets and settings etc. or try anotherkiwi's suggestion to 'wait until the speed drops below 23-22 kph before I start pedaling again.' I think that problem was with the particular controllers used. The discussions in the Links below may be of help.


 
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ilexk

Finding my (electric) wheels
Jul 26, 2021
6
0
If both controllers are 15A, they should give the same power and torque. Obviously, for the KT, you need to be on level 5 to get max power any other level will reduce power (assuming you have p3=1)

There are some settings that can effect the power for the KT controller. C5=0 allows maximum current. Any other value of C5 would not be 15A. Different versions can have different software, so it's not possible to give exact guidance.

C14 affects the pedal assist. C14=4 should give the highest selectable value, but I'm not sure whether C14=0 by default gives the max. Try both.

If neither of those solves the problem, you need to fix a wattmeter between the batter and controller to see what's going on, then solder the shunt to get what you need.

One more thing: You should have P3=1 for current control. P3=0 is speed control and has a different max speed for each of the 5 levels.
Hello Saneagle!!

I will try to verify what you tell me and report results.

Thank you
 

ilexk

Finding my (electric) wheels
Jul 26, 2021
6
0
The above appears similar to the reported problem with the earlier Pendleton Somerby bikes and some other kits. You could check your PAS magnets and settings etc. or try anotherkiwi's suggestion to 'wait until the speed drops below 23-22 kph before I start pedaling again.' I think that problem was with the particular controllers used. The discussions in the Links below may be of help.


Hello Sturmie!!

I have read the comments of the two threads that you have referred to me and I think that the seller should know about these defects in the product.

I feel cheated and physically hurt by pedaling without electrical assistance.

I will continue to inform you.....

Thank you
 

ilexk

Finding my (electric) wheels
Jul 26, 2021
6
0
If both controllers are 15A, they should give the same power and torque. Obviously, for the KT, you need to be on level 5 to get max power any other level will reduce power (assuming you have p3=1)

There are some settings that can effect the power for the KT controller. C5=0 allows maximum current. Any other value of C5 would not be 15A. Different versions can have different software, so it's not possible to give exact guidance.

C14 affects the pedal assist. C14=4 should give the highest selectable value, but I'm not sure whether C14=0 by default gives the max. Try both.

If neither of those solves the problem, you need to fix a wattmeter between the batter and controller to see what's going on, then solder the shunt to get what you need.

One more thing: You should have P3=1 for current control. P3=0 is speed control and has a different max speed for each of the 5 levels.
Hello again !!

I have checked the C parameter configurations
The C5 was at 10, I changed it to 0 and now it delivers greater power, at level 1 it almost pushes as much as before at 2.

I would like to know what is the best configuration of all the P and C parameters of the KT-LCD3

It would be of great help to me if you sent me.

Bafang 36v 250w CST 26" hub motor
Controller KT sine wave 15A
Display KT-LCD 3

Thank you so much

Greetings
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
3,540
1,763
Telford
Hello again !!

I have checked the C parameter configurations
The C5 was at 10, I changed it to 0 and now it delivers greater power, at level 1 it almost pushes as much as before at 2.

I would like to know what is the best configuration of all the P and C parameters of the KT-LCD3

It would be of great help to me if you sent me.

Bafang 36v 250w CST 26" hub motor
Controller KT sine wave 15A
Display KT-LCD 3

Thank you so much

Greetings
Make sure P3=1 for current control. That should give you differnt power in each level instead of different speed and same power.