Controller not pushing enough amps when high speed

[Danishblunt]

Really curious sitauation here, I use a KT-LCD3 and cannot seem to program the controller to do what I want. For whatever reason on level 5 it powers the hub perfecly fine up intil around 20km/h, after that it lowers the current so that the torque isnt that great, if I use my throttle it will power it as it should and can easily get up to 40km/h, however with pedal assist alone it just doesnt seem to want to power it fully after 20km/h, is there any setting I am not understanding here?

To clearify, it still boosts the speed up to 40km/h+ but once I hit 20km/h it just gives maybe half the amps it should and I know its not a limitation since when i add power via throttle it just goes for it as it should.

 

[E-HP]

Really curious sitauation here, I use a KT-LCD3 and cannot seem to program the controller to do what I want. For whatever reason on level 5 it powers the hub perfecly fine up intil around 20km/h, after that it lowers the current so that the torque isnt that great, if I use my throttle it will power it as it should and can easily get up to 40km/h, however with pedal assist alone it just doesnt seem to want to power it fully after 20km/h, is there any setting I am not understanding here?

To clearify, it still boosts the speed up to 40km/h+ but once I hit 20km/h it just gives maybe half the amps it should and I know its not a limitation since when i add power via throttle it just goes for it as it should.

thats how electric motors work.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0

controllers don't push amps; motors pull amps.

 

[larsb]

Jah E-HP, but this question is about the KT-LCD3 and its’ functions. It was some years since i had one but that kit i had didn’t give full assist without the LCD connected and settings set but on PAS without LCD it delivered highest assist, the opposite of ypur controller. Must be something in the settings. One thing i can think of is if your PAS magnet count is set too high, then controller logic will not give the full assist since it measures you pedalling slow also when you’re at max cadence.

 

[E-HP]

Jah E-HP, but this question is about the KT-LCD3 and its’ functions.

Ah, OK. Then I'd want to know that C3 is set to a valid number (not above 5), and what P4 and C4 and maybe C5 are set to. If they look correct, then maybe doing a restore to defaults and setting the parameters up again may cure it.

 

[Danishblunt]

Really curious sitauation here, I use a KT-LCD3 and cannot seem to program the controller to do what I want. For whatever reason on level 5 it powers the hub perfecly fine up intil around 20km/h, after that it lowers the current so that the torque isnt that great, if I use my throttle it will power it as it should and can easily get up to 40km/h, however with pedal assist alone it just doesnt seem to want to power it fully after 20km/h, is there any setting I am not understanding here?

To clearify, it still boosts the speed up to 40km/h+ but once I hit 20km/h it just gives maybe half the amps it should and I know its not a limitation since when i add power via throttle it just goes for it as it should.

thats how electric motors work.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0

controllers don't push amps; motors pull amps.

A hub motor has no sense of powerdraw. it's simply put just wires and magnets, the more power you push through it the faster and/or stronger it will spin.
Motors pull amps and controllers push amps, that's how it works. If a controller doesn't push amps, that means there is no current flowing to the hub, so your statement doesnt make sense. Af far as the hub is concerned it takes whatever power the controller delivers, no questions asked.

As for the KT, I suspected as much, I'm not very familair with the KT-LCD's display yet. Ill look up the settings and report back. I'll also try restore to default and see if it does anything.

 

[E-HP]

Really curious sitauation here, I use a KT-LCD3 and cannot seem to program the controller to do what I want. For whatever reason on level 5 it powers the hub perfecly fine up intil around 20km/h, after that it lowers the current so that the torque isnt that great, if I use my throttle it will power it as it should and can easily get up to 40km/h, however with pedal assist alone it just doesnt seem to want to power it fully after 20km/h, is there any setting I am not understanding here?

To clearify, it still boosts the speed up to 40km/h+ but once I hit 20km/h it just gives maybe half the amps it should and I know its not a limitation since when i add power via throttle it just goes for it as it should.

thats how electric motors work.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0

controllers don't push amps; motors pull amps.

A hub motor has no sense of powerdraw. it's simply put just wires and magnets, the more power you push through it the faster and/or stronger it will spin.

Motor will pull 0 amps at full speed at full throtttle, if there's no wind resistance or rolling resitance, even if the controller is capable of 1000A. Lift the wheel and see (you may have a few watts to overcome the resistance from the bearings and some losses). Ride up a 20% grade at full throttle, and it will pull a lot of amps, no change to the throttle setting or controller, just the motor pulling more amps.

https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=20&bopen=true&cont_b=C35&motor_b=M2706&batt_b=B4816_GA&hp_b=0&frame_b=cust_0_0

so 0W vs 1400W in this example, only change is the motor pulling more current.

35A controller vs 1000A controller, same top speed.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0&bopen=true&cont_b=cust_1000_3000_0.03_V&motor_b=M2706&batt_b=B4816_GA&hp_b=0&frame_b=mountain

 

[Danishblunt]

Really curious sitauation here, I use a KT-LCD3 and cannot seem to program the controller to do what I want. For whatever reason on level 5 it powers the hub perfecly fine up intil around 20km/h, after that it lowers the current so that the torque isnt that great, if I use my throttle it will power it as it should and can easily get up to 40km/h, however with pedal assist alone it just doesnt seem to want to power it fully after 20km/h, is there any setting I am not understanding here?

To clearify, it still boosts the speed up to 40km/h+ but once I hit 20km/h it just gives maybe half the amps it should and I know its not a limitation since when i add power via throttle it just goes for it as it should.

thats how electric motors work.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0

controllers don't push amps; motors pull amps.

A hub motor has no sense of powerdraw. it's simply put just wires and magnets, the more power you push through it the faster and/or stronger it will spin.

Motor will pull 0 amps at full speed at full throtttle, if there's no wind resistance or rolling resitance, even if the controller is capable of 1000A. Lift the wheel and see (you may have a few watts to overcome the resistance from the bearings and some losses). Ride up a 20% grade at full throttle, and it will pull a lot of amps, no change to the throttle setting or controller, just the motor pulling more amps.

https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=20&bopen=true&cont_b=C35&motor_b=M2706&batt_b=B4816_GA&hp_b=0&frame_b=cust_0_0

so 0W vs 1400W in this example, only change is the motor pulling more current.

35A controller vs 1000A controller, same top speed.
https://ebikes.ca/tools/simulator.html?motor=M2706&batt=B4816_GA&cont=C35&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0&bopen=true&cont_b=cust_1000_3000_0.03_V&motor_b=M2706&batt_b=B4816_GA&hp_b=0&frame_b=mountain

Can you elaborate what you're trying to explain because so far you're not telling me anything new, my question on the topic was simply how to make sure the controller doesnt cut half the current at around 25KM/H, I'm fully aware that acontroller will slowly drop its current the faster the engine spins, it goes in a somewhat linear curve, however mine cuts in half a certain speed. As mentioned above, a hub has no concept of power draw, it takes what it can get, the controller is designed to push less current the faster you go because otherwise you get an incredibly wasteful system that drains the battery extremely fast for little gain.

Thanks to me explaining how the system roughly works, I think I know whats causing the problem. Ill report back.

EDIT: Since I'm running sensorless, the settings on how fast the motor spins etc. have to be accurate, otherwise the controller will get confused and cause this little glitch. Turns out setting the proper p1 and p2 settings solved the issue.

 

[john61ct]

Between any source and load, the source only makes a maximum current level available.

It is up to the load to (try to) pull the current it wants or needs.

That is what is meant by "controllers do not push current", the actual flow rate if any is determined by the motor until it reaches the maximum the controller will provide.

 

[larsb]

C’mon guys, skip the motor/controller theory (even though you’re obviously correct)

It’s friday and the problem was in controller settings, not in kV*V or too low current available.

 

[AHicks]

If this KT controller is actually limiting the amount of power to the motor at a particular speed, and max speed is set at 99km/h, C5=10 and C14=3 -

First, I'd be really surprised, and second, I'd wonder where it came from? Under the notion nothing is impossible, I suppose there is a remote possibility an OEM bike manf. has set a limit in the firmware that cannot be adjusted....

 

[E-HP]

If this KT controller is actually limiting the amount of power to the motor at a particular speed, and max speed is set at 99km/h, C5=10 and C14=3 -

First, I'd be really surprised, and second, I'd wonder where it came from? Under the notion nothing is impossible, I suppose there is a remote possibility an OEM bike manf. has set a limit in the firmware that cannot be adjusted....

Seems to be acting like C5 is applying differently to PAS vs throttle, which is not normal state, and therefore the suggestion of performing a factory reset.