KT-LCD3 & PAS not functioning

This is my first E-bike build. Battery completed. Motor mounted on a test frame mounted to a lab bench to test all out before I transfer everything to the frame I want to use. All working fine, motor, throttle, brake cut-off, regen. The only issue I see is the PAS. When I move the pedals the motor takes off and goes to top speed as I spin the pedal crank even though the PAS is set @ 1. Once I stop spinning the pedal crank the motor stops. Is this the expected behavior? I see no difference between PAS levels 1-5. I thought the behavior would be a slower motor speed at the lower PAS settings.

I asked the vendor, Leafbike what the P1 and P2 settings should be. His response was P1- 46 and P2- 0. Tried that and same behavior, This is the motor kit I am using https://www.leafbike.com/products/d...w-rear-hub-motor-bike-conversion-kit-904.html

Any thoughts on why the PAS settings do not affect the speed rotation of the motor? I am overlooking something here.

Motor Specs:
>. Engine: Bldc hub motor
>>. Voltage: 36V
>>. Power: 750W
>>. Efficiency: 87.5%
>>. Max speed: 69.0 kmh – 43.1 mph
>>. Mechanical brake: Disk or V
>>. Freewheel / Cassette: space for 6 or 7 gears
>>. Cable location: shaft end , LEFT
>>. Cable length:100cm / 40"
>>. Install: spacing of 135mm fork
>>. Noise: < 60 db
>>. Surface: Black painted

>. Driver: brushless controller
>>. MOSFET: 12 PCS
>>. With LCD: YES
>>. Rated Voltage: DC 36 Volts
>>. Min. Voltage: DC 30 ± 0.5 V
>>. Rated power: 750 Watts
>>. Casing material: aluminium
>>. Maximum Current: 26 A ± 1 Amps
>>. Thermal: aluminum shell and the substrate
>>. 3 phase 120° brushless motor
>>. Operating Conditions: -20~45 °C
>>. Waterproof design
>>. Size: 171 mm L × 82 mm W × 42 mm H

NEW LCD , More Function:
* Cruise
* Forward & Rackward (Optional)
* Regen brake
* Kmh & mph (Optional)
* Set Max speed ( 0 ~ 72 kmh / 45 mph )
* Pedal assist ( 1 - 5 )

Thank you

Might work differently under load. I've never really tested an LCD3 PAS on a test stand except to verify that the PAS sensor was working.

stevecahill said:

I asked the vendor, Leafbike what the P1 and P2 settings should be. His response was P1- 46 and P2- 0. Tried that and same behavior,

Click to expand...

What is C1 set to?

I have two sensors, a 8 and a 12 magnet sensor. The 8 magnet sensor I have tried just a few combinations. This sensor spins the wheel but at top speed. The 12 magnet sensor I cannot get to work at all the vendors recommended C1 setting of 6. Its LED lights up, but no motor action

I ordered the color KT-LCD8H so programing changes will be less of a nuisance than the LCD3 so I can try combinations more quickly.

Good point mentioned by docw009 that perhaps under load this will react differently. However setting C14 =1 for the 10 watts limitation the motor is drawing way over that amount so that is not being limited. Not sure if another setting like C5 is needed to be set?

Curious what other controllers are compatible with the KT LCD's, and perhaps controller is behaving badly with this KT-LCD? Any links to purchase would be helpful.

Thank you for your support.

Regards
Steve

Everything is correct. You have P3=1, which gives power control, where each level of PAS gives a different level of power without speed limit, so with no load the wheel will spin to maximum speed. This should be no problem because when you ride the bike, the low power on the level 1 is not enough to give you any speed.

If you want, you can change it to P3=0, where each level of PAS gives a different maximum speed without power restriction. The problem with that is that you get maximum power as soon as you start, which makes control at low speed difficult.

Thank you. Good useful explanation.

This is the split sensor that I could not get to work. Need to try more combinations. https://www.amazon.com/gp/product/B01N482WPI/ref=ox_sc_act_title_1?smid=A3063PLKK9YWLG&psc=1

stevecahill said:

This is the split sensor that I could not get to work. Need to try more combinations. https://www.amazon.com/gp/product/B01N482WPI/ref=ox_sc_act_title_1?smid=A3063PLKK9YWLG&psc=1

Click to expand...

I think C1=7 is for a 12 magnet disc on the chain ring/right side of the crank, and C1=3 is on the left side crank.

Are you using the same sensor with different rings? You might have the disk backward with the split rings. You can mix things up, but they only work properly with the magnets on the disk coming at the sensor with correct polarity/direction. The number of magnets used in P1 is for smoother operation, but if everything is properly installed, in my experience it will try to work no matter what is programed. ALways a first time, I guess.

Magnets have a north and south poles, and the sensor is smart enough to tell the difference. Otherwise you could work PAS by pedaling backward. Not good.

And if you were changing sensors, it's not guaranteed that these things have the same wiring order. I bought a PAS sensor and controller from the same outfit, and both connectors were female, which kind of forces one to make it right,

stevecahill said:

This is the split sensor that I could not get to work. Need to try more combinations. https://www.amazon.com/gp/product/B01N482WPI/ref=ox_sc_act_title_1?smid=A3063PLKK9YWLG&psc=1

Click to expand...

Those sensors are sometimes handed. There are two possibilities for magnet orientation (flip) and two possibilities for rotation direction, which makes 4 combinations. On some PAS sensors, only one combination works, which means that you have to put it on the right side of the bike.

Even if it's not a handed one, there are still two possibilities, but only one works. That means that it can work in only one direction out of forward and reverse. If it doesn’t work when you pedal forwards, check whether it works when you pedal backwards. If it does, flip the magnet disc.

Is there s smaller diameter PAS Sensor compatible with the LCD3 display?

Dboy24 said:

Is there s smaller diameter PAS Sensor compatible with the LCD3 display?

Click to expand...

Welcome to the forum :thumb:

Yes, the V12 by KT is about the same diameter as my bottom bracket housing. I used it when I had my KT controller and LCD3:

http://www.szktdz.com/en/news_show.php?article_id=392