shayati

My wife and I each have identical ebikes. They use paddle assist as well as throttle control. When we ride our bikes, the motor power cuts off intermittently. There is no problem with battery. We have noticed the cutting off happens when the digital speed reader reads wrong speed. For example, as we are traveling say at 10 km/hr speed, the speed jumps to 50 or 80, which is obviously the wrong sensing of the speed. That causes the bikes to cut of motor power for safely. It seems that there is electrical noise in the control system or speed evaluation. This happens to both of our bikes. After the cut off, the system starts again and we can use the power until it cuts off again.

Any suggestions or solutions?

bowlofsalad

How do you know there is no problem with the battery?

I'd start with the connectors, namely the phase and hall sensors, but checking them all is likely a good place to start. Unplug and inspect for any corrosion or bent pins. Disconnect and reconnect the connections a few times. You might also add a dab of dielectric grease on the connection pins.

Be sure none of the connectors are able to bounce around at all.

The_Equalizer

Hi,
The reason it cuts power is the speed limiter is kicking in. You said it your self, the speed jumps up way past the limiter and gets cut.
The problem lies in the speed pick up, the speed sensor, sending unit, or controller.
Depending on your bike the problem can be in the controller or in the motor. Causes can be a short, moisture, or contaminates like iron filing that got picked up by the magnets in the speed sensors causing false readings.

Treatment is cleaning the surfaces of the pickups. If that doesn't work it may lie deeper in the electronics.
Hope it helps.

shayati

Thank you for responding. I found the digital display unit's name for my bikes and found some information about it on line. It is BigStone C300. There is some instruction on how to increase the MAX speed setting, but unfortunately, it does not work on my bikes. Even if did work, the MAX speed that I can set is about 50, but as I mentioned in my original post, my speed jumps to 60 over even 80. When I looked at the specification of the display unit (i.e., BigStone C300) I found out that it is connected to the bike's electronics via a five pin connector. One of the pins is for speed. I am thinking of not connecting that pin to the display unit and am hoping that the "read" speed will be zero, and therefore the power will not cut off. Will this work?

The_Equalizer

It most likely will register ZERO for speed. This will make all the pedal assist levels not regulate. You will lose your speedo. The motor has a hard wired speed limiter in it. usually rated on RPM, depending on the motor output.
I wouldn't consider this so much of a fix, more of a working broken.

arnie799

I also have the power cutting off occasionally. It does not happen on a regular basis. I phoned the manufacturer, and they suggested i spray all the contacts in the controller and battery contacts with an electrical spray that is supposed to help. I haven't tried that yet, as the problem only happens occasionally. I found that turning off the power for a minute or 2 and then turning it back on, resolves the problem. I don't see how the spray and my solution are related, and perhaps someone on the forum can explain it to me.

350htrr

If it isn't cutting off because you are going too fast I would check the switch on the brake lever that cuts the motor when you put the brakes on (if you have one), maybe needing some adjustment too...

The_Equalizer

You might want to listen to them.