How does controller know bike speed?

[baltimorebiker]

I have a LCD display from this kit

http://www.ebay.com/itm/291340427977

I was wondering if I need to install the PAS sensor if I want the LCD display to pick up bike speed. Or can the controller sense speed based off motor feedback?

I don't want to install PAS because it seems unnecessary.

Thanks for help. I'm just getting into Ebiking.

 

[lbz5mc12]

It senses it from the motor. You don't need the pas sensor. The pas sensor is for pedal assist which works by attaching a magnetic ring and sensor to the bottom bracket. It then senses your pedal cadence when you're pedaling and engages the motor. I have a similar more expensive kit and the odometer/speedometer function is built into the wheel.

 

[d8veh]

Most people that have never used a PAS think that they don't need it. Many that have one, like me, wouldn't want a bike without one. It works like a cruise control, so a lot easier than a throttle when you have five selectable levels from the LCD. Depending on what bottom bracket you have, a PAS only takes 5 minutes to fit and there's no downside to it, so why not fit it?

Your controller should pick up the speed from one of the motor hall sensors. Often there's a separate connector on the controller to use an optional wheel-speed sensor, like on a cycle computer. You can choose which source of speed signal to use by settings in the LCD. Make sure you get the LCD instruction manual with your kit.

 

[dogman dan]

PAS can be fine for folks that can always pedal. I can't always pedal, so not for me.

On some kits with display, a 9th wire to the motor is the speed sensor wire. Others can pick up speed just from the halls or phase signal rpm. Not sure how it works really. But for example, a CA has speed sensing, without a pickup on the wheel.

 

[melodious]

My first Ebike didn't have PAS, and was throttle only. I thought that was the way to go. My second bike had PAS as a mandatory option so I kept it. Now, I prefer the PAS as I like "pedal & power" feel. I probably ride 85% PAS & 15% throttle (overtaking others & power maneuvers). Most casual folks with a PAS & throttle option more than likely ride like me.

But, if you have a bike rigged for +40mph wheelie bike, definitely keep PAS off the menu until you can program a ramp up.