Hey guys!

I have a Samebike CY20. The throttle was not working alongside the horn. Only the pedal assist PAS was working. Suddenly, the PAS stopped, and now nothing is working except the display and light. I tried a replacement for the throttle, but it did not work.

AFAIK, it is a controller issue. OFC, hard to tell without looking, but has anyone faced this issue?

How to check compatibe controller on Aliexpress? Here is the one sold by the producer company https://samebike.com/products/samebike-original-controller?variant=45213220798645

The AI is suggesting me to replace the controller with KT (Kunteng) Sine Wave 36V/48V 350W. Any idea if this would work out?

Thanks in advance!

Edited March 29Mar 29 by Hazem

3 hours ago, Hazem said:

Hey guys!

I have a Samebike CY20. The throttle was not working alongside the horn. Only the pedal assist PAS was working. Suddenly, the PAS stopped, and now nothing is working except the display and light. I tried a replacement for the throttle, but it did not work.

AFAIK, it is a controller issue. OFC, hard to tell without looking, but has anyone faced this issue?

How to check compatibe controller on Aliexpress? Here is the one sold by the producer company https://samebike.com/products/samebike-original-controller?variant=45213220798645

The AI is suggesting me to replace the controller with KT (Kunteng) Sine Wave 36V/48V 350W. Any idea if this would work out?

Thanks in advance!

You shouldn't buy any parts until you know what's wrong. Start by getting yourself a multimeter, then do these tests.:

1. Measure the voltage at controller's battery connector. Obviously should be battery voltage. 36v - 42v for a 36v battery would be an acceptable range, but if you've fully charged the battery and it's less than 41v, it needs some sorting.

2. Measure the voltage on the 5v rail. You can measure that between any ground (black) and any of the reds going to throttle, PAS or motor halls. It should be around 5v.

3. Check throttle signal wire voltage on it's connector while connected. it's the wire that's not red or black on the throttle connector. Should change from about 1v to 4v when you twist the throttle. If there's more than one wire, your meter will find it. It's the one that's between 1v and 4v, assuming that it works.

4. Check that the pedal assist sensor is pulsing. Measure the PAS signal wire while turning the pedals slowly. Should pulse 5v on and off every time a magnet passes the sensor. The signal wire is the one that's not red or black.

5. Check the motor hall signal wires (blue green and yellow) on the motor connector at the controller. They should each pulse with 5v going on and off as you rotate the wheel BACKWARDS.

6. Mosfet test. Disconnect the motor cable and battery from the controller. Measure the resistance (200k scale) between the red battery connection and each of the three phase wire connections, then repeat with the black battery wire. Each set of 3 readings should be the same as each other and in the range 7K -24K. Though can be higher as long as they're all the same. Due to the capacitor across the battery wire, you can get a constantantly changing measurement while it charges. In that case, try swapping your probes round. Even though can be a moving result, the only important thing is that all three move in a similar way.

 If your bike passes all those tests, it should work, so then you can look at any settings or other logical causes, like stuck brake switches.

Edited March 29Mar 29 by D8veh