PAS Too fast on my recent conversion

[cfunni]

A little background. My wife has a Electra Townie Go, and the Battery died, and due to the communication requirement from the controller to the BMS system in the battery, just changing to a generic battery would not work. So I purchased a basic kit with a LCD display, controller, throttle, PAS, and a generic 36V battery. Install went fine and bike works good except the PAS is too fast. Throttle is as expected, but when using PAS, level 1 is no assist, level 2 or above is way too fast. The motor is a rear hub 250 Watt OEM from the original set up. I have made every change in the configuration with no change in the PAS reaction. The bike surges way to quick, and speed is too fast to the point I am afraid my wife might loose control. I have ordered a new PAS to change, but if anyone has a suggestion I am all ears.
Thanks
Craig in Houston

 

[stancecoke]

but if anyone has a suggestion I am all ears.

What kind of controller do you have?
You could reduce the max current allowed, to get less acceleration. This can be done by the display settings for some controllers or by a shunt mod on the PCB....
A new PAS will not help as the PAS signal is digital, it works or it works not. And obviously it works in your setup.

 

[cfunni]

What kind of controller do you have?
You could reduce the max current allowed, to get less acceleration. This can be done by the display settings for some controllers or by a shunt mod on the PCB....

Its a generic controller, and I did originally set the current to 20A, as that is the Max, and then I changed it to 12A and did not see any difference, but I did not go below 12. I will change that tonight when I get home, Thanks

 

[Diggs]

Many display/controllers (like the KT3) allow the whole PAS range to be turned up or down (low-med-high). Not sure if yours does or not. Need more details.

 

[cfunni]

The display is GD01, and the motor controller is a no name with limited details. I made several changes via the display, and nothing changed the rapid start or speed under the PAS. I can select the PAS to be 3 or 5 levels, but under any setting level 1 was no PAS, and level 2 was too rapid of a start and too fast. I am next going to lower the current setting, but still open to ideas.

 

[stancecoke]

The display is GD01, and the motor controller is a no name with limited details.

So good luck. The behavior of these controllers is unpredictable, as there are umpteen different firmware variants that all behave differently in some way. Search for "Greentime" or "Brainpower" in this forum.

 

[docw009]

Try 5 PAS Levels if it is set for 3 levels. If the display and controller came as part of a kit, they should work together, but am bothered by PAS 1 being off. It should be PAS 0.

I've been down this road with the SW900 display, Full speed in PAS 1, Now I only use the KT display/controller combo. It doesn't allow individual PAS adjustments, but the overall current can be set between 50% and 100%. Allows tuning to 80W in PAS 1. That's slow.

 

[E-HP]

The display is GD01, and the motor controller is a no name with limited details. I made several changes via the display, and nothing changed the rapid start or speed under the PAS. I can select the PAS to be 3 or 5 levels, but under any setting level 1 was no PAS, and level 2 was too rapid of a start and too fast. I am next going to lower the current setting, but still open to ideas.

Thanks for these clues. Not sure why you were reluctant to provide any details about what equipment you purchased before.
Displays and their firmware are manufacturer specific. The GD01 is used with DC MOTO/JN controllers. That brand controllers exhibit the behavior you describe. The KT controllers that others have mentioned, have a more gradual application of power in all PAS level, and the amount of power, as mentioned, can also be adjusted. My guess is that level 1 would work without adjustment, but you have options if you need them. The other issue is you bought a ~700w controller for your 250w bike, which is probably ok with a KT controller, but magnifies the issues using your “generic” controller.

 

[2old]

I have an identical problem (initially the bike accelerates the same on all levels of assist). It seems like the only solution is a programmable system (ebikesca/Grin), but I use the bike so infrequently, PAS was removed and just the throttle is employed.

 

[cfunni]

Thanks for these clues. Not sure why you were reluctant to provide any details about what equipment you purchased before.
Displays and their firmware are manufacturer specific. The GD01 is used with DC MOTO/JN controllers. That brand controllers exhibit the behavior you describe. The KT controllers that others have mentioned, have a more gradual application of power in all PAS level, and the amount of power, as mentioned, can also be adjusted. My guess is that level 1 would work without adjustment, but you have options if you need them. The other issue is you bought a ~700w controller for your 250w bike, which is probably ok with a KT controller, but magnifies the issues using your “generic” controller.

Thanks for the info, I was not reluctant to inform just sipping my coffee this morning and looking for ideas. Here is a pic of the controller. I have no problem swapping out to a KT controller. Things are starting make sense now.

 

[cfunni]

Another piece I just thought about. This bike has a Torque Sensor on it from the original factory electronics. If I am going to install a better controller is using the torque sensor a better option than a PAS setup?

 

[stancecoke]

I have an identical problem (initially the bike accelerates the same on all levels of assist).

There are two different types of PAS assistance.
- Speed levels. The bike accelerates to the speed that is associated to the level with full power. So level 1 is e.g. 8 mph, level 2 12mph.... But this works only properly, if the controller has the right setting for the number of pole pairs and the mechanical gear ratio of the motor. Otherwise the controller can't know the correct speed of the wheel.

- power levels. The level in the display sets the battery current. So level 1 will push with e.g. 3amps * 36V = 108W, level 2 with 6 amps * 36V= 216 W

You seem to have speed levels, as the acceleration is the same in all levels.

With a torque sensor, the motor assists proportional to the riders human power. Motor power = factor defined by the level * cadence * torque on the pedal.
This provides a much more natural riding experience. You can reach the top speed in each level, there is no need to change the assist level all the time. Simple PAS assistance is like riding a moped somehow, you have to operate the display buttons all the time to adapt the assistance to the speed.

But you would have to post a photo of the torquesensor and the connector to tell you, which controller is suitable for that sensor.

 

[2old]

I'm familiar with torque sensors since there is one on my Haibike e-hardtail, but this system doesn't have anything resembling one. This is an inexpensive front hub kit with a small controller (under the top tube near the head tube). As mentioned, I'm happy with the throttle since I can regulate motor power with it and pedal as much as I care to. The unloaded speed is 25 mph, same as with me riding the bike.

 

[cfunni]

Update on my issue , repair of my wifes Electra Townie. Following suggestions from this group I replaced the controller with a KT-15A Controller, and a KT-LCD11 Display. Works just like I expected it to work. Thank you for the help and suggestions.

​

 

[johnscura]

A little background. My wife has a Electra Townie Go, and the Battery died, and due to the communication requirement from the controller to the BMS system in the battery, just changing to a generic battery would not work. So I purchased a basic kit with a LCD display, controller, throttle, PAS, and a generic 36V battery. Install went fine and bike works good except the PAS is too fast. Throttle is as expected, but when using PAS, level 1 is no assist, level 2 or above is way too fast. The motor is a rear hub 250 Watt OEM from the original set up. I have made every change in the configuration with no change in the PAS reaction. The bike surges way to quick, and speed is too fast to the point I am afraid my wife might loose control. I have ordered a new PAS to change, but if anyone has a suggestion I am all ears.
Thanks
Craig in Houston

Hi Craig, I have a 2014 Townie in need of a charger. Would you consider selling the Townie charger and maybe the dead Townie battery?