An odd problem

[mcsg]

Howdy EBike masters!
Got an issue with a cheap ebike. no power levels or gears.
Wires-Red 5v, Green-ranges from .8v to 3.6 at full throttle and Black is earthed.
While pedalling, bike has full throttle assist without throttle being touched (green wire .8v)
No pedalling and full throttle (green wire 3.6v) very slow motor turning, basically no assist.
Pedalling and using full throttle (3.6v) supplies no assist.
Stop pedalling, release throttle and full assist engages.
Given the throttle supplies a change in voltage to the controller in either option, can I canel out this?
Rendering the controller being the issue?

 

[mcsg]

Just disconnected throttle and the assist kicks in when pedalling so this would mean the controller is completely disregarding the throttle?

 

[fechter]

It would seem that way.

Any chance the PAS and throttle wires got swapped around?

 

[docw009]

The previous owner must have gotten the three throttle wires for output, power, and ground mixed up. I know you said the throttle signal appears to work normally whe you measured it, but maybe the throttle ground is on the wrong pin.

If you probe the connector with nothing plugged into it, you can verify power/ground. Third by default is signal.

 

[mcsg]

It would seem that way.

Any chance the PAS and throttle wires got swapped around?

I don't think so, I've taken the bike out of the stand and I''l have a look tomorrow, but have this pic. It looks like the plugs can't be swapped.

 

[mcsg]

The previous owner must have gotten the three throttle wires for output, power, and ground mixed up. I know you said the throttle signal appears to work normally whe you measured it, but maybe the throttle ground is on the wrong pin.

If you probe the connector with nothing plugged into it, you can verify power/ground. Third by default is signal.

Anything is possble, have a look at the pic I posted, silicon in plugs seems to be original, but I can check tomorrow. I didn't have the earth in that plug connected to the multimeter lead, I just used the battery earth wire in stead, as it was easier and further away so that I wasn't going to accidently short out the wires with probes while checking.

 

[yooper2001]

Could the CONTROLLER 5v and signal wires be colored wrong (swapped) therefore switching the real input to the controller? The bike gets full throttle (5v) from supply when not touched, and the voltage drags down when resistance of throttle is increased? Just a thought.

 

[mcsg]

To answer a few vaild questions which I appreciate. The connectors can't be mismatched and the wiring has not been played with since new given the glue in the back of the plugs, so the question of swaping wires hasn't happened it all looks original. I checked the earth/ground on the plug and it has continuity to earth. So my thinking the is the throttle circuit in the box is fried or there maybe a dry solder joint or component failure is my guess.

 

[docw009]

There is no standard for the throttle connector when you use JST plugs. Manufacturers will switch plug genders and pin positions at will. So even if it looks original, someone could have bought a replacement throttle.

By the way, the throttle should be a Hall sensor IC, not a potentiometer. Powered by 5 volts and a magnet rotates over the IC.

You really want to check the throttle output referenced to the ground wire of the throttle connector. The controller may have used a separate ground wire in that circuit, It's a well known condition that if the ground wire on the throttle breaks, the input floats to 4.3 volt with throttle off, That's detected as full throttle.

 

[mcsg]

There is no standard for the throttle connector when you use JST plugs. Manufacturers will switch plug genders and pin positions at will. So even if it looks original, someone could have bought a replacement throttle.

By the way, the throttle should be a Hall sensor IC, not a potentiometer. Powered by 5 volts and a magnet rotates over the IC.

You really want to check the throttle output referenced to the ground wire of the throttle connector. The controller may have used a separate ground wire in that circuit, It's a well known condition that if the ground wire on the throttle breaks, the input floats to 4.3 volt with throttle off, That's detected as full throttle.

I hear what you're saying, the bike has worked fine previously, so that should put your first comment to bed.

I get .8v no throttle and then 3.6v at full throttle when the cranks are not turning, obvisously the throttle is getting an earth and the wheel turns accordingly. Also, i would see the voltage rise to 4.3 with throttle off and cranks turning but it stays at .8v.
Checked throttle operation at the plug using the throttle signal and earth wires just to make sure and have the same result as using battery earth confirming no break in earth wire and validating the earth continuity test I did before.